WO2009009792A1

WO2009009792A1 - Injection system and method

Info

Publication number: WO2009009792A1
Application number: PCT/US2008/069972
Authority: WO
Inventors: Adrian Vuyk, Jr.; Greg Galloway; Gordon Tibbitts; Jim B. Terry; Jody Estes; Jason Tichenor; Darrell Traylor; Donald Woods
Original assignee: Particle Drilling Technologies, Inc.
Priority date: 2007-07-12
Filing date: 2008-07-14
Publication date: 2009-01-15

Abstract

An injection system and method is described. In several exemplary embodiments, the injection system and method may be a part of, and/or used with, a system and method for excavating a subterranean formation.

Description

INJECTION SYSTEM AND METHOD

Cross-Reference to Related Applications

[0001] This application claims priority to and the benefit of co-pending U.S. Provisional Application Ser. No. 60/959,207, filed July 12, 2007, the full disclosure of which is hereby incorporated by reference herein. This application is a continuation in part of U.S. utility patent application serial number 11/773,355, attorney docket number 13978.105084US, filed on 7/3/2007, PCT patent application serial number PCT/US07/72794, attorney docket number 13978.105084WO, filed on 7/3/2007, U.S. provisional patent application number 60/899,135, filed on February 2, 2007 (attorney docket number 37163.00061); U.S. provisional patent application serial number 60/818,480, filed on July 3, 2006 (attorney docket no. 37163.00059); and pending application no. 10/897,196, filed on July 22. 2004 (attorney docket no. 13978.105012 formerly 37163.00012), the disclosures of which are incorporated herein by reference.

[0002] This application is related to U.S. provisional patent application serial number 60/463,903, filed on April 16, 2003 (attorney docket no. 13978.105035 formerly 37163.00017); U.S. Patent No. 6,386,300, issued on May 14. 2002, which was filed as application no. 09/665,586 on September 19, 2000 (attorney docket no. 13978.105037 formerly 37163.00023); U.S. Patent No. 6,581,700, issued on June 24, 2003, which was filed as application no. 10/097,038 on March 12, 2002 (attorney docket no. 13978.105034 formerly 37163.00024); U.S. Patent No. 7,398,838, issued on July 15, 2008, which was filed as application no. 11/204,981, filed on August 16, 2005 (attorney docket no. 37163.00006); U.S. Patent No. 7,343,987, issued on March 18, 2008, which was filed as application no. 11/204,436, filed on August 16, 2005 (attorney docket no. 13978.105041 formerly 37163.00007); pending application no. 11/204,862, filed on August 16, 2005 (attorney docket no. 13978.105042 formerly 37163.00008); pending application no. 11/205,006, filed on August 16, 2005 (attorney docket no. 13978.105038 formerly 37163.00009); pending application no. 11/204,722, filed on August 16, 2005 (attorney docket no. 13978.105053 formerly 37163.00010); U.S. Patent No. 7,398,839, issued on July 15, 2008, which was filed as application no. 11/204,442, filed on August 16, 2005 (attorney docket no. 13978.105018 formerly 37163.00011); U.S. Patent No. 7,258,176, issued August 21, 2007, which was filed as application no. 10/825,338, filed on April 15, 2004 (attorney docket no. 13978.105060 formerly 37163.00018); pending application no. 10/558,181, filed on May 27, 2004 (attorney docket no. 13978.105032 formerly 37163.00045); pending application no. 11/344,805, filed on February 1, 2006 (attorney docket no. 13978.105059 formerly 37163.00047); pending application no. 60/746,855, filed on May 9, 2006 (attorney docket no. 13978.105071 formerly 37163.00057); the disclosures of which are incorporated herein by reference.

Background

[0003] This disclosure generally relates to a system and method for injecting particles into a flow region in connection with, for example, excavating a formation. The formation may be excavated in order to, for example, form a wellbore for the purpose of oil and gas recovery, construct a tunnel, or form other excavations in which the formation is cut, milled, pulverized, scraped, sheared, indented, and/or fractured, hereinafter referred to collectively as cutting.

Brief Description of the Drawings

[0004] Fig. 1 is an isometric view of an excavation system according to an embodiment.

[0005] Fig.2 illustrates an impactor impacted with a formation.

[0006] Fig. 3 illustrates an impactor embedded into the formation at an angle to a normalized surface plane of the target formation.

[0007] Fig. 4 illustrates an impactor impacting a formation with a plurality of fractures induced by the impact.

[0008] Fig. 5 is an elevational view of a drilling system utilizing a first embodiment of a drill bit.

[0009] Fig. 6 is a top plan view of the bottom surface of a well bore formed by the drill bit of Fig. 5.

[0010] Fig. 7 is a sectional view of a sequencing valve for use with one or more of the embodiments of the present disclosure.

[0011] Fig. 8A is a sectional view of an alternate embodiment of a sequencing valve for use with one or more of the embodiments of the present disclosure. [0012] Fig. 8B is a sectional view of an alternate embodiment of a sequencing valve for use with one or more of the embodiments of the present disclosure.

[0013] Fig. 9 is a schematic view of an injection system according to another embodiment.

[0014] Fig. 10 is an elevationai view of an injection system according to another embodiment.

[0015] Fig. 11 is a perspective partially exploded view of an embodiment of a concrete pump.

[0016] Fig. 12a is a perspective view of an embodiment of a selector valve assembly. [0017] Fig. 12b is an overhead view of the selector valve assembly of Fig. 12a. [0018] Fig. 12c is a frontal view of the selector valve assembly of Fig. 12a.

[0019] Figs. 13a - 13h depict, in frontal and perspective views, an operational sequence of an embodiment of a selector valve assembly.

[0020] Fig. 14 is a perspective view of an embodiment of a selector valve assembly.

[0021] Fig. 15 is a frontal view of an embodiment for a valve seal.

[0022] Fig. 16 is a sectional view of a portion of the valve seal of Fig. 15.

[0023] Fig. 17 is a perspective view of an embodiment of a seal with a transfer tube.

[0024] Fig. 18 is a cross sectional view of the seal of Fig. 17.

Detailed Description of the Illustrative Embodiments

[0025] In the drawings and description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale. Certain features of the disclosure may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present disclosure is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. This application claims priority to and the benefit of co-pending U.S. Provisional Application Ser. No. 60/959,207, filed My 12, 2007, the full disclosure of which is hereby incorporated by reference herein.

[0026] Figs. 1 and 2 illustrate an embodiment of an excavation system 1 comprising the use of solid material particles, or impactors, 100 to engage and excavate a subterranean formation 52 to create a wellbore 70. The excavation system 1 may comprise a pipe string 55 comprised of collars 58, pipe 56, and a kelly 50. An upper end of the kelly 50 may interconnect with a lower end of a swivel quill 26. An upper end of the swivel quill 26 may be rotatably interconnected with a swivel 28. The swivel 28 may include a top drive assembly (not shown) to rotate the pipe string 55. Alternatively, the excavation system 1 may further comprise a body member such as, for example, a drill bit 60 to cut the formation 52 in cooperation with the solid material impactors 100. The drill bit 60 may be attached to the lower end 55B of the pipe string 55 and may engage a bottom surface 66 of the wellbore 70. The drill bit 60 may be a roller cone bit, a fixed cutter bit, an impact bit, a spade bit, a mill, an impregnated bit, a natural diamond bit, or other suitable implement for cutting rock or earthen formation. Referring to Fig. 1, the pipe string 55 may include a feed, or upper, end 55A located substantially near the excavation rig 5 and a lower end 55B including a nozzle 64 supported thereon. The lower end 55B of the string 55 may include the drill bit 60 supported thereon. The excavation system 1 is not limited to excavating a wellbore 70. The excavation system and method may also be applicable to excavating a tunnel, a pipe chase, a mining operation, or other excavation operation wherein earthen material or formation may be removed.

[0027] In another exemplary embodiment, the present system may be used to inject any solid particulate material into a wellbore. Exemplary particles may be magnetic or nonmagnetic solid particles. Exemplary uses of the of the present system include, but are not limited to, casing exits, preventing seepage loss, and fracturing a formation.

[0028] To excavate the wellbore 70, the swivel 28, the swivel quill 26, the kelly 50, the pipe string 55, and a portion of the drill bit 60, if used, may each include an interior passage that allows circulation fluid to circulate through each of the aforementioned components. The circulation fluid may be withdrawn from a tank 6, pumped by a pump 2, through a through medium pressure capacity line 8, through a medium pressure capacity flexible hose 42, through a gooseneck 36, through the swivel 28, through the swivel quill 26, through the kelly 50, through the pipe string 55, and through the bit 60.

[0029] The excavation system I further comprises at least one nozzle 64 on the lower 55B of the pipe string 55 for accelerating at least one solid material impactor 100 as they exit the pipe string 100. The nozzle 64 is designed to accommodate the impactors 100, such as an especially hardened nozzle, a shaped nozzle, or an "impactor" nozzle, which may be particularly adapted to a particular application. The nozzle 64 may be a type that is known and commonly available. The nozzle 64 may further be selected to accommodate the impactors 100 in a selected size range or of a selected material composition. Nozzle size, type, material, and quantity may be a function of the formation being cut, fluid properties, impactor properties, and/or desired hydraulic energy expenditure at the nozzle 64. If a drill bit 60 is used, the nozzle or nozzles 64 may be located in the drill bit 60.

[0030] The nozzle 64 may alternatively be a conventional dual-discharge nozzle. Such dual discharge nozzles may generate: (1) a radially outer circulation fluid jet substantially encircling a jet axis, and/or (2) an axial circulation fluid jet substantially aligned with and coaxial with the jet axis, with the dual discharge nozzle directing a majority by weight of the plurality of solid material impactors into the axial circulation fluid jet. A dual discharge nozzle 64 may separate a first portion of the circulation fluid flowing through the nozzle 64 into a first circulation fluid stream having a first circulation fluid exit nozzle velocity, and a second portion of the circulation fluid flowing through the nozzle 64 into a second circulation fluid stream having a second circulation fluid exit nozzle velocity lower than the first circulation fluid exit nozzle velocity. The plurality of solid material impactors 100 may be directed into the first circulation fluid stream such that a velocity of the plurality of solid material impactors 100 while exiting the nozzle 64 is substantially greater than a velocity of the circulation fluid while passing through a nominal diameter flow path in the lower end 55B of the pipe string 55, to accelerate the solid material impactors 100.

[0031] Each of the individual impactors 100 is structurally independent from the other impactors. For brevity, the plurality of solid material impactors 100 may be interchangeably referred to as simply the impactors 100. The plurality of solid material impactors 100 may be substantially rounded and have either a substantially non-uniform outer diameter or a substantially uniform outer diameter. The solid material impactors 100 may be substantially spherically shaped, non-hollow, formed of rigid metallic material, and having high compressive strength and crush resistance, such as steel shot, ceramics, depleted uranium, and multiple component materials. Although the solid material impactors 100 may be substantially a non-hollow sphere, alternative embodiments may provide for other types of solid material impactors, which may include impactors 100 with a hollow interior. The impactors may be magnetic or non-magnetic. The impactors may be substantially rigid and may possess relatively high compressive strength and resistance to crushing or deformation as compared to physical properties or rock properties of a particular formation or group of formations being penetrated by the wellbore 70.

[0032] The impactors may be of a substantially uniform mass, grading, or size. The solid material impactors 100 may have any suitable density for use in the excavation system 1. For example, the solid material impactors 100 may have an average density of at least 470 pounds per cubic foot.

[0033] Alternatively, the solid material impactors 100 may include other metallic materials, including tungsten carbide, copper, iron, or various combinations or alloys of these and other metallic compounds. The impactors 100 may also be composed of non-metallic materials, such as ceramics, or other man-made or substantially naturally occurring non- metallic materials. Also, the impactors 100 may be crystalline shaped, angular shaped, sub- angular shaped, selectively shaped, such as like a torpedo, dart, rectangular, or otherwise generally non-spherically shaped.

[0034] The impactors 100 may be selectively introduced into a fluid circulation system, such as illustrated in Fig. 1, near an excavation rig 5, circulated with the circulation fluid (or "mud"), and accelerated through at least one nozzle 64. "At the excavation rig" or "near an excavation rig" may also include substantially remote separation, such as a separation process that may be at least partially carried out on the sea floor.

[0035] Introducing the impactors 100 into the circulation fluid may be accomplished by any of several known techniques. For example, the impactors 100 may be provided in an impactor storage tank 94 near the rig 5 or in a storage bin 82. A screw elevator 14 may then transfer a portion of the impactors at a selected rate from the storage tank 94, into a slurrification tank 98. A pump 10, such as a progressive cavity pump may transfer a selected portion of the circulation fluid from a mud tank 6, into the slurrification tank 98 to be mixed with the impactors 100 in the tank 98 to form an impactor concentrated slurry. An impactor introducer 96 may be included to pump or introduce a plurality of solid material impactors 100 into the circulation fluid before circulating a plurality of impactors 100 and the circulation fluid to the nozzle 64. The impactor introducer 96 may be a progressive cavity pump capable of pumping the impactor concentrated slurry at a selected rate and pressure through a slurry line 88, through a slurry hose 38, through an impactor slurry injector head 34, and through an injector port 30 located on the gooseneck 36, which may be located atop the swivel 28. The swivel 36, including the through bore for conducting circulation fluid therein, may be substantially supported on the feed, or upper, end of the pipe string 55 for conducting circulation fluid from the gooseneck 36 into the latter end 55a, The upper end 55A of the pipe string 55 may also include the kelly 50 to connect the pipe 56 with the swivel quill 26 and/or the swivel 28. The circulation fluid may also be provided with rheological properties sufficient to adequately transport and/or suspend the plurality of solid material impactors 100 within the circulation fluid.

[0036] The solid material impactors 100 may also be introduced into the circulation fluid by withdrawing the plurality of solid material impactors 100 from a low pressure impactor source 98 into a high velocity stream of circulation fluid, such as by venturi effect. For example, when introducing impactors 100 into the circulation fluid, the rate of circulation fluid pumped by the mud pump 2 may be reduced to a rate lower than the mud pump 2 is capable of efficiently pumping. In such event, a lower volume mud pump 4 may pump the circulation fluid through a medium pressure capacity line 24 and through the medium pressure capacity flexible hose 40.

[0037] The circulation fluid may be circulated from the fluid pump 2 and/or 4, such as a positive displacement type fluid pump, through one or more fluid conduits 8, 24, 40, 42, into the pipe string 55. The circulation fluid may then be circulated through the pipe string 55 and through the nozzle 64. The circulation fluid may be pumped at a selected circulation rate and/or a selected pump pressure to achieve a desired impactor and/or fluid energy at the nozzle 64.

[0038] The pump 4 may also serve as a supply pump to drive the introduction of the impactors 100 entrained within an impactor slurry, into the high pressure circulation fluid stream pumped by mud pumps 2 and 4. Pump 4 may pump a percentage of the total rate of fluid being pumped by both pumps 2 and 4, such that the circulation fluid pumped by pump 4 may create a venturi effect and/or vortex within the injector head 34 that inducts the impactor slurry being conducted through the line 42, through the injector head 34, and then into the high pressure circulation fluid stream.

[0039] From the swivel 28, the slurry of circulation fluid and impactors may circulate through the interior passage in the pipe string 55 and through the nozzle 64. As described above, the nozzle 64 may alternatively be at least partially located in the drill bit 60. Each nozzle 64 may include a reduced inner diameter as compared to an inner diameter of the interior passage in the pipe string 55 immediately above the nozzle 64. Thereby, each nozzle 64 may accelerate the velocity of the slurry as the slurry passes through the nozzle 64. The nozzle 64 may also direct the slurry into engagement with a selected portion of the bottom surface 66 of wellbore 70. The nozzle 64 may also be rotated relative to the formation 52 depending on the excavation parameters. To rotate the nozzle 64, the entire pipe string 55 may be rotated or only the nozzle 64 on the end of the pipe string 55 may be rotated while the pipe string 55 is not rotated. Rotating the nozzle 64 may also include oscillating the nozzle 64 rotationally back and forth as well as vertically, and may further include rotating the nozzle 64 in discrete increments. The nozzle 64 may also be maintained rotationally substantially stationary. [0040] The circulation fluid may be substantially continuously circulated during excavation operations to circulate at least some of the plurality of solid material impactors 100 and the formation cuttings away from the nozzle 64. The impactors 100 and fluid circulated away from the nozzle 64 may be circulated substantially back to the excavation rig 5, or circulated to a substantially intermediate position between the excavation rig 5 and the nozzle 64.

[0041] If the drill bit 60 is used, the drill bit 60 may be rotated relative to the formation 52 and engaged therewith by an axial force (WOB) acting at least partially along the wellbore axis 75 near the drill bit 60. The bit 60 may also comprise a plurality of bit cones 62, which also may rotate relative to the bit 60 to cause bit teeth secured to a respective cone to engage the formation 52, which may generate formation cuttings substantially by crushing, cutting, or pulverizing a portion of the formation 52. The bit 60 may also be comprised of a fixed cutting structure that may be substantially continuously engaged with the formation 52 and create cuttings primarily by shearing and/or axial force concentration to fail the formation, or create cuttings from the formation 52. To rotate the bit 60, the entire pipe string 55 may be rotated or only the bit 60 on the end of the pipe string 55 may be rotated while the pipe string 55 is not rotated. Rotating the drill bit 60 may also include oscillating the drill bit 60 rotationaily back and forth as well as vertically, and may further include rotating the drill bit 60 in discrete increments.

[0042] Also alternatively, the excavation system 1 may comprise a pump, such as a centrifugal pump, having a resilient lining that is compatible for pumping a solid-material laden slurry. The pump may pressurize the slurry to a pressure greater than the selected mud pump pressure to pump the plurality of solid material impactors 100 into the circulation fluid. The impactors 100 may be introduced through an impactor injection port, such as port 30. Other alternative embodiments for the system 1 may include an impactor injector for introducing the plurality of solid material impactors 100 into the circulation fluid.

[0043] As the slurry is pumped through the pipe string 55 and out the nozzles 64, the impactors 100 may engage the formation with sufficient energy to enhance the rate of formation removal or penetration (ROP). The removed portions of the formation may be circulated from within the wellbore 70 near the nozzle 64, and carried suspended in the fluid with at least a portion of the impactors 100, through a wellbore annulus between the OD of the pipe string 55 and the ID of the wellbore 70. [0044] At the excavation ring 5, the returning slurry of circulation fluid, formation fluids (if any), cuttings, and impactors 100 may be diverted at a nipple 76, which may be positioned on a BOP stack 74. The returning slurry may flow from the nipple 76, into a return flow line

15, which maybe comprised of tubes 48, 45, 16, 12 and flanges 46, 47. The return line 15 may include an impactor reclamation tube assembly 44, as illustrated in Fig. 1, which may preliminarily separate a majority of the returning impactors 100 from the remaining components of the returning slurry to salvage the circulation fluid for recirculation into the present wellbore 70 or another wellbore. At least a portion of the impactors 100 may be separated from a portion of the cuttings by a series of screening devices, such as the vibrating classifiers 84, to salvage a reusable portion of the impactors 100 for reuse to re-engage the formation 52. A majority of the cuttings and a majority of non-reusable impactors 100 may also be discarded.

[0045] The reclamation tube assembly 44 may operate by rotating tube 45 relative to tube

16. An electric motor assembly 22 may rotate tube 44. The reclamation tube assembly 44 comprises an enlarged tubular 45 section to reduce the return flow slurry velocity and allow the slurry to drop below a terminal velocity of the impactors 100, such that the impactors 100 can no longer be suspended in the circulation fluid and may gravitate to a bottom portion of the tube 45. This separation function may be enhanced by placement of magnets near and along a lower side of the tube 45. The impactors 100 and some of the larger or heavier cuttings may be discharged through discharge port 20. The separated and discharged impactors 100 and solids discharged through discharge port 20 may be gravitationally diverted into a vibrating classifier 84 or may be pumped into the classifier 84. A pump (not shown) capable of handling impactors and solids, such as a progressive cavity pump may be situated in communication with the flow line discharge port 20 to conduct the separated impactors 100 selectively into the vibrating separator 84 or elsewhere in the circulation fluid circulation system.

[0046] The excavation system 1 creates a mass-velocity relationship in a plurality of the solid material impactors 100, such that an impactor 100 may have sufficient energy to structurally alter the formation 52 in a zone of a point of impact. The mass-velocity relationship may be satisfied as sufficient when a substantial portion by weight of the solid material impactors 100 may by virtue of their mass and velocity at the exit of the nozzle 64, create a structural alteration as claimed or disclosed herein. Impactor velocity to achieve a desired effect upon a given formation may vary as a function of formation compressive strength, hardness, or other rock properties, and as a function of impactor size and circulation fluid rheological properties. A substantial portion means at least five percent by weight of the plurality of solid material impactors that are introduced into the circulation fluid.

[0047] The impactors 100 for a given velocity and mass of a substantial portion by weight of the impactors 100 are subject to the following mass-velocity relationship. The resulting kinetic energy of at least one impactor 100 exiting a nozzle 64 is at least 0.075 FtLbs or has a minimum momentum of 0.0003 LbfSec.

[0048] Kinetic energy is quantified by the relationship of an object's mass and its velocity. The quantity of kinetic energy associated with an object is calculated by multiplying its mass times its velocity squared. To reach a minimum value of kinetic energy in the mass- velocity relationship as defined, small particles such as those found in abrasives and grits, must have a significantly high velocity due to the small mass of the particle. A large particle, however, needs only moderate velocity to reach an equivalent kinetic energy of the small particle because its mass may be several orders of magnitude larger.

[0049] The velocity of a substantial portion by weight of the plurality of solid material impactors 100 immediately exiting a nozzle 64 may be as slow as 100 feet per second and as fast as 1000 feet per second, immediately upon exiting the nozzle 64.

[0050] The velocity of a majority by weight of the impactors 100 may be substantially the same, or only slightly reduced, at the point of impact of an impactor 100 at the formation surface 66 as compared to when leaving the nozzle 64. Thus, it may be appreciated by those skilled in the art that due to the close proximity of a nozzle 64 to the formation being impacted, the velocity of a majority of impactors 100 exiting a nozzle 64 may be substantially the same as a velocity of an impactor 100 at a point of impact with the formation 52. Therefore, in many practical applications, the above velocity values may be determined or measured at substantially any point along the path between near an exit end of a nozzle 64 and the point of impact, without material deviation from the scope of this disclosure.

[0051] In addition to the impactors 100 satisfying the mass-velocity relationship described above, a substantial portion by weight of the solid material impactors 100 have an average mean diameter of between approximately 0.050 to 0.500 of an inch, including increments of .01 inches in this range [0052] To excavate a formation 52, the excavation implement, such as a drill bit 60 or impactor 100, must overcome minimum, in-situ stress levels or toughness of the formation

52. These minimum stress levels are known to typically range from a few thousand pounds per square inch, to in excess of 65,000 pounds per square inch. To fracture, cut, or plastically deform a portion of formation 52, force exerted on that portion of the formation 52 typically should exceed the minimum, in-situ stress threshold of the formation 52. When an impactor

100 first initiates contact with a formation, the unit stress exerted upon the initial contact point may be much higher than 10,000 pounds per square inch, and may be well in excess of one million pounds per square inch. The stress applied to the formation 52 during contact is governed by the force the impactor 100 contacts the formation with and the area of contact of the impactor with the formation. The stress is the force divided by the area of contact. The force is governed by Impulse Momentum theory whereby the time at which the contact occurs determines the magnitude of the force applied to the area of contact. In cases where the particle is contacting a relatively hard surface at an elevated velocity, the force of the particle when in contact with the surface is not constant, but is better described as a spike.

However, the force need not be limited to any specific amplitude or duration. The magnitude of the spike load can be very large and occur in just a small fraction of the total impact time.

If the area of contact is small the unit stress can reach values many times in excess of the in situ failure stress of the rock, thus guaranteeing fracture initiation and propagation and structurally altering the formation 52.

[0053] A substantial portion by weight of the solid material impactors 100 may apply at least 5000 pounds per square inch of unit stress to a formation 52 to create the structurally altered zone Z in the formation. The structurally altered zone Z is not limited to any specific shape or size, including depth or width. Further, a substantial portion by weight of the impactors 100 may apply in excess of 20,000 pounds per square inch of unit stress to the formation 52 to create the structurally altered zone Z in the formation. The mass-velocity relationship of a substantial portion by weight of the plurality of solid material impactors 100 may also provide at least 30,000 pounds per square inch of unit stress.

[0054] A substantial portion by weight of the solid material impactors 100 may have any appropriate velocity to satisfy the mass-velocity relationship. For example, a substantial portion by weight of the solid material impactors may have a velocity of at least 100 feet per second when exiting the nozzle 64. A substantial portion by weight of the solid material impactors 100 may also have a velocity of at least 100 feet per second and as great as 1200 feet per second when exiting the nozzle 64. A substantial portion by weight of the solid material impactors 100 may also have a velocity of at least 100 feet per second and as great as 750 feet per second when exiting the nozzle 64. A substantial portion by weight of the solid material impactors 100 may also have a velocity of at least 350 feet per second and as great as 500 feet per second when exiting the nozzle 64.

[0055] Impactors 100 may be selected based upon physical factors such as size, projected velocity, impactor strength, formation 52 properties and desired impactor concentration in the circulation fluid. Such factors may also include; (a) an expenditure of a selected range of hydraulic horsepower across the one or more nozzles, (b) a selected range of circulation fluid velocities exiting the one or more nozzles or impacting the formation, and (c) a selected range of solid material impactor velocities exiting the one or more nozzles or impacting the formation, (d) one or more rock properties of the formation being excavated, or (e), any combination thereof.

[0056] Referring to Figs. 1 - 4, a substantial portion by weight of the impactors 100 may engage the formation 52 with sufficient energy to enhance creation of a wellbore 70 through the formation 52 by any or a combination of different impact mechanisms. First, an impactor 100 may directly remove a larger portion of the formation 52 than may be removed by abrasive-type particles. In another mechanism, an impactor 100 may penetrate into the formation 52 without removing formation material from the formation 52. A plurality of such formation penetrations, such as near and along an outer perimeter of the wellbore 70 may relieve a portion of the stresses on a portion of formation being excavated, which may thereby enhance the excavation action of other impactors 100 or the drill bit 60. Third, an impactor 100 may alter one or more physical properties of the formation 52. Such physical alterations may include creation of micro-fractures and increased brittleness in a portion of the formation 52, which may thereby enhance effectiveness the impactors 100 in excavating the formation 52. The constant scouring of the bottom of the borehole also prevents the build up of dynamic filtercake, which can significantly increase the apparent toughness of the formation 52.

[0057] Fig. 2 illustrates an impactor 100 that has been impaled into a formation 52, such as a lower surface 66 in a wellbore 70. For illustration purposes, the surface 66 is illustrated as substantially planar and transverse to the direction of impactor travel 100a. The impactors 100 circulated through a nozzle 64 may engage the formation 52 with sufficient energy to effect one or more properties of the formation 52.

[0058] A portion of the formation 52 ahead of the impactor 100 substantially in the direction of impactor travel T may be altered such as by micro-fracturing and/or thermal alteration due to the impact energy. In such occurrence, the structurally altered zone Z may include an altered zone depth D. An example of a structurally altered zone Z is a compressive zone Z1, which may be a zone in the formation 52 compressed by the impactor 100. The compressive zone Z1 may have a length L1, but is not limited to any specific shape or size. The compressive zone Z1 may be thermally, altered due to impact energy.

[0059] An additional example of a structurally altered zone 102 near a point of impaction may be a zone of micro-fractures Z2. The structurally altered zone Z may be broken or otherwise altered due to the impactor 100 and/or a drill bit 60, such as by crushing, fracturing, or micro-fracturing.

[0060] Fig. 2 also illustrates an impactor 100 implanted into a formation 52 and having created an excavation E wherein material has been ejected from or crushed beneath the impactor 100. Thereby the excavation E may be created, which as illustrated in Fig. 3 may generally conform to the shape of the impactor 100.

[0061] Figs. 3 and 4 illustrate excavations E where the size of the excavation may be larger than the size of the impactor 100. In Fig.2, the impactor 100 is shown as impacted into the formation 52 yielding an excavation depth D.

[0062] An additional theory for impaction mechanics in cutting a formation 52 may postulate that certain formations 52 may be highly fractured or broken up by impactor energy. Fig. 4 illustrates an interaction between an impactor 100 and a formation 52. A plurality of fractures F and micro-fractures MF may. be created in the formation 52 by impact energy.

[0063] An impactor 100 may penetrate a small distance into the formation 52 and cause the displaced or structurally altered formation 52 to "splay out" or be reduced to small enough particles for the particles to be removed or washed away by hydraulic action. Hydraulic particle removal may depend at least partially upon available hydraulic horsepower and at least partially upon particle wet-ability and viscosity. Such formation deformation may be a basis for fatigue failure of a portion of the formation by "impactor contact," as the plurality of solid material impactors 100 may displace formation material back and forth.

[0064] Each nozzle 64 may be selected to provide a desired circulation fluid circulation rate, hydraulic horsepower substantially at the nozzle 64, and/or impactor energy or velocity when exiting the nozzle 64. Each nozzle 64 may be selected as a function of at least one of (a) an expenditure of a selected range of hydraulic horsepower across the one or more nozzles 64, (b) a selected range of circulation fluid velocities exiting the one or more nozzles 64, and (c) a selected range of solid material impactor 100 velocities exiting the one or more nozzles 64.

[0065] One or more controllable variables or parameters may be altered, including at least one of: (a) rate of impactor 100 introduction into the circulation fluid, (b) impactor 100 size, (c) impactor 100 velocity, (d) drill bit nozzle 64 selection, (e) the selected circulation rate of the circulation fluid, (f) the selected pump pressure, and (g) any of the monitored excavation parameters.

[0066] To alter the rate of impactors 100 engaging the formation 52, the rate of impactor 100 introduction into the circulation fluid may be altered. The circulation fluid circulation rate may also be altered independent from the rate of impactor 100 introduction. Thereby, the concentration of impactors 100 in the circulation fluid may be adjusted separate from the fluid circulation rate. Introducing a plurality of solid material impactors 100 into the circulation fluid may be a function of impactor 100 size, circulation fluid rate, nozzle rotational speed, wellbore 70 size, and a selected impactor 100 engagement rate with the formation 52. The impactors 100 may also be introduced into the circulation fluid intermittently during the excavation operation. The rate of impactor 100 introduction relative to the rate of circulation fluid circulation may also be adjusted or interrupted as desired.

[0067] The plurality of solid material impactors 100 may be introduced into the circulation fluid at a selected introduction rate and/or concentration to circulate the plurality of solid material impactors 100 with the circulation fluid through the nozzle 64. The selected circulation rate and/or pump pressure, and nozzle selection may be sufficient to expend a desired portion of energy or hydraulic horsepower in each of the circulation fluid and the impactors 100. [0068] An example of an operative excavation system 1 may comprise a bit 60 with an 8 1/2 inch bit diameter. The solid material impactors 100 may be introduced into the circulation fluid at a rate of 12 gallons per minute. The circulation fluid containing the solid material impactors may be circulated through the bit 60 at a rate of 462 gallons per minute. In one embodiment, substantial portion by weight of the solid material impactors may have an average mean diameter of between about 0.05" to about 0.15, in another embodiment impactor average diameter is about 0.075" to about 0.125", in another embodiment impactor average diameter is about 0.078" in another embodiment impactor average diameter is about 0.100". The following parameters will result in approximately a 27 feet per hour penetration rate into Sierra White Granite. In this example, the excavation system may produce 1413 solid material impactors 100 per cubic inch with approximately 3.9 million impacts per minute against the formation 52. On average, 0.00007822 cubic inches of the formation 52 are removed per impactor 100 impact. The resulting exit velocity of a substantial portion of the impactors 100 from each of the nozzles 64 would average 495.5 feet per second. The kinetic energy of a substantial portion by weight of the solid material impacts 100 would be approximately 1.14 Ft Lbs., thus satisfying the mass-velocity relationship described above.

[0069] Another example of an operative excavation system 1 may comprise a bit 60 with an 8 ½ inch bit diameter. The solid material impactors 100 may be introduced into the circulation fluid at a rate of 12 gallons per minute. The circulation fluid containing the solid material impactors may be circulated through the nozzle 64 at a rate of 462 gallons per minute. A substantial portion by weight of the solid material impactors may have an average mean diameter of 0.075". The following parameters will result in approximately a 35 feet per hour penetration rate into Sierra White Granite. In this example, the excavation system 1 may produce 3350 solid material impactors 100 per cubic inch with approximately 9.3 million impacts per minute against the formation 52. On average, 0.0000428 cubic inches of the formation 52 are removed per impactor 100 impact The resulting exit velocity of a substantial portion of the impactors 100 from each of the nozzles 64 would average 495.5 feet per second. The kinetic energy of a substantial portion by weight of the solid material impacts 100 would be approximately 0.240 Ft Lbs., thus satisfying the mass-velocity relationship described above.

[0070] In addition to impacting the formation with the impactors 100, the bit 60 may be rotated while circulating the circulation fluid and engaging the plurality of solid material impactors 100 substantially continuously, or selectively intermittently. The nozzle 64 may also be oriented to cause the solid material impactors 100 to engage the formation 52 with a radially outer portion of the bottom hole surface 66. Thereby, as the drill bit 60 is rotated, the impactors 100, in the bottom hole surface 66 ahead of the bit 60, may create one or more circumferential kerfs. The drill bit 60 may thereby generate formation cuttings more efficiently due to reduced stress in the surface 66 being excavated, due to the one or more substantially circumferential kerfs in the surface 66.

[0071] The excavation system 1 may also include inputting pulses of energy in the fluid system sufficient to impart a portion of the input energy in an impactor 100. The impactor 100 may thereby engage the formation 52 with sufficient energy to achieve a structurally altered zone Z. Pulsing of the pressure of the circulation fluid in the pipe string 55, near the nozzle 64 also may enhance the ability of the circulation fluid to generate cuttings subsequent to impactor 100 engagement with the formation 52.

[0072] Each combination of formation type, bore hole size, bore hole depth, available weight on bit, bit rotational speed, pump rate, hydrostatic balance, circulation fluid rheology, bit type, and tooth/cutter dimensions may create many combinations of optimum impactor presence or concentration, and impactor energy requirements. The methods and systems of this disclosure facilitate adjusting impactor size, mass, introduction rate, circulation fluid rate and/or pump pressure, and other adjustable or controllable variables to determine and maintain an optimum combination of variables. The methods and systems of this disclosure also may be coupled with select bit nozzles, downhole tools, and fluid circulating and processing equipment to effect many variations in which to optimize rate of penetration.

[0073] Fig. 5 shows an alternate embodiment of the drill bit 60 (Fig. 1.) and is referred to, in general, by the reference numeral 110 and which is located at the bottom of a well bore 120 and attached to a drill string 130. The drill bit 110 acts upon a bottom surface 122 of the well bore 120. The drill string 130 has a central passage 132 that supplies drilling fluids to the drill bit 110 as shown by the arrow Ai. The drill bit 110 uses the drilling fluids and solid material impactors 100 when acting upon the bottom surface 122 of the well bore 120. The drilling fluids then exit the well bore 120 through a well bore annulus 124 between the drill string 130 and the inner wall 126 of the well bore 120. Particles of the bottom surface 122 removed by the drill bit 110 exit the well bore 120 with the drilling fluid through the well bore annulus 124 as shown by the arrow A₂. The drill bit 110 creates a rock ring 142 at the bottom surface 122 of the well bore 120.

[0074] Referring now to Fig. 6, a top view of the rock ring 124 formed by the drill bit 110 is illustrated. An excavated interior cavity 144 is worn away by an interior portion of the drill bit 110 and the exterior cavity 146 and inner wall 126 of the well bore 120 are worn away by an exterior portion of the drill bit 110. The rock ring 142 possesses hoop strength, which holds the rock ring 142 together and resists breakage. The hoop strength of the rock ring 142 is typically much less than the strength of the bottom surface 122 or the inner wall 126 of the well bore 120, thereby making the drilling of the bottom surface 122 less demanding on the drill bit 110. By applying a compressive load and a side load, shown with arrows 141, on the rock ring 142, the drill bit 110 causes the rock ring 142 to fracture. The drilling fluid 140 then washes the residual pieces of the rock ring 142 back up to the surface through the well bore annulus 124.

[0075] Fig. 10 schematically represents an example of a drilling system 320 employing a concrete pump 322 as described herein. The concrete pump 322 pressurizes a slurry of fluid and impactors that is then discharged to a slurry discharge line 324. The slurry discharge line 324 terminates with a pressurized drilling fluid line 330 at an injection point 325. Drilling fluid pressurized by a pressure source 328 flows from the pressure source 328 through the pressurized drilling fluid line 330 and to the injection point 325, where the impactor and fluid slurry is injected therein. The concrete pump 322 pressurizes the slurry to a set pressure of sufficient magnitude ensure the impactor fluid slurry is injectable into the pressurized drilling fluid line 330. The set pressure may be at a value where injecting the impactor fluid slurry into the pressurized drilling fluid line 330 is by pressure differential and without an eductor. As will be discussed in more detail below, the impactor and fluid slurry pressure is maintained at a relatively constant value in the slurry discharge line 324 thereby preventing pressurized drilling fluid ingress from the pressurized drilling fluid line 330 into the slurry discharge line 324. An optional one way valve 326 is illustrated in the slurry discharge line 324 and represents one manner of preventing such ingress. Examples of one way valves 326 include check valves, float valves, and motor operated valves.

[0076] A combined stream of impactor and fluid slurry and pressurized drilling fluid flows in a drilling system fluid feed line 327 connected downstream of the injection point 325. The combined stream is fed to a drill string 334 driven by one of a swivel 332 or a top drive disposed over a wellbore 338. The drill string 334 is used to create the wellbore 338 through a subterranean formation 340. As previously described, the combined flow of impactor fluid slurry and drilling fluid is injected into the drill string 334 where it is directed to a drill bit 336 attached to the lower terminal end of the drill string 334. The fluid exits the drill bit 336 through nozzles (not shown), an upward stream 342 of fluid, impactors, and formation cuttings flows from the bit 336 and through an annulus 335 formed between the drill string 334 and wellbore 338 walls. The upward flow 342 is collected at surface where the impactors can be reclaimed for future use.

[0077] The system described herein is not limited to injecting a slurry of impactors and fluid into a drilling fluid line, but can also be used to inject other fluids or solids into a stream being directed within a wellbore. In one example of use, a pump as described herein pressurizes a stream having a proppant that is directed downhole. The downhole operation involving the proppant may include a fracing process that fractures subterranean formations for enhancing hydrocarbon production from within the formation. Other fluids considered for use with the pumping system include acidizing fluids, brines, alcohols, and other wellbore treating substances.

[0078] In an exemplary embodiment, as illustrated in Fig. 7, a valve system 800 is illustrated which is adapted to maintain a constant pressure during cycling between the intake and discharge steps of the first and second pump cylinders of a concrete pump. Valve system 800 is adapted to alternate between two feed sources, cylinders 802 and 804 respectively. As illustrated in Fig. 7, the first cylinder 802 is shown as the discharge cylinder and second cylinder 804 is shown as the filling cylinder. The valve body 820 includes an inlet 810 which can be rotated between the first and second cylinder outlets, 805 and 807 respectively. In a first position, the valve inlet 810 is aligned with the outlet 805 of the first pump cylinder 802 and the corresponding port 806. The concrete, slurry, or other material is pumped out of cylinder 802, though the first cylinder outlet 805, and into port 806 in the sequencing valve. The flow paths through which the material enters through inlet 810 and exits the valve body 820 are not required to be in the same plane to function properly and may take multiple forms by one skilled in the art of material flow. The material is pumped into the valve, and exits through the outlet 814. As the material is pumped out of the first cylinder 802, material is simultaneously introduced into the second cylinder 804. Upon completion of the pumping of the contents of the first cylinder 802, the valve inlet 810 rotates to facilitate the discharge of the material from the second cylinder 804 that was being loaded while the first cylinder 802 was discharging. After the contents of the second cylinder 804 have been pumped through the valve system 800, the valve inlet 810 rotates to again align with the first cylinder 802 and the process is repeated.

[0079] In an exemplary embodiment, the pump is a Schwing BP8800 concrete pump having which includes Rock Valve, a Big Rock Valve, or a similar functioning valve. In certain exemplary embodiments, the concrete pump may be modified so that the output pressure of the cylinder is approximately the same as the piston pressure. Such modifications may include, but are not limited to, decreasing the area of the cylinder, increasing the operating pressure, and/or increasing the piston size. In certain embodiments, the output horsepower of the engine associated with the concrete pump may be increased. In certain other embodiments, the rock valve may be modified to include wings or shoulder (as described herein) to maintain a more constant output pressure and reduce a decrease in pressure between intake and discharge steps during pumping with the concrete pump. In certain embodiments, a check valve may also be employed with the rock valve and the wings/shoulders employed at the inlet of the valve. In certain other embodiments, a pressure compensation device may be employed with the pump.

[0080] In an exemplary embodiment, the slurry feed of solid material impactors and drilling fluid to the pump contains from 50-90% by volume of solid material impactors and from 10-50% by volume of drilling fluids. In another exemplary embodiment, the slurry feed to the pump contains from 55-75% by volume of solid material impactors and from 25-45% by volume of drilling fluids. In another exemplary embodiment, the slurry feed to the pump contains from 58-65% by volume of solid material impactors and from 35-42% by volume of drilling fluids. In another exemplary embodiment, the slurry feed to the pump contains approximately 62% by volume of weight solid material impactors and approximately 38% by volume of drilling fluids.

[0081] In an exemplary embodiment, the feed rate of impactors to the cement pump is at least about 2 gal/min. In another exemplary embodiment, the feed rate of impactors to the cement pump is at least about 10 gal/min. In yet another exemplary embodiment, the feed rate of impactors to the cement pump is at least about 15 gal/min. In yet another exemplary embodiment, the feed rate of impactors to the cement pump is at least about 20 gal/min. Ih yet another exemplary embodiment, the feed rate of impactors to the cement pump is at least about 30 gal/min. In yet another exemplary embodiment, the feed rate of impactors to the cement pump is at least about 40 gal/min. In yet another exemplary embodiment, the feed rate of impactors to the cement pump is at least about 50 gal/min. Optionally, the concrete pump cylinder angle with respect to horizontal may be adjusted to control the impactor feed rated.

[0082] In an exemplary experimental embodiment, a test was conducted using a Schwing BP8800 concrete pump for injection of a slurry of solid material impactors. The concrete pump was operated at 2,100 RPM, a piston pressure of 4,900 psi, a high cylinder pressure of 3,900 psi and a low cylinder pressure of 1,700 psi. The concrete pump was able to inject the slurry of solid material impactors at a rate of up to 17.0 gpm at a standpipe pressure of greater than 3,000 psi.

[0083] The pressure on port 814 shown in Fig. 7 remains relatively constant because the port 814 is fluidically coupled with a closed system. This closed system generally consists of cylinder 802 during its discharge cycle, cylinder 804 during its discharge stroke or the valve body during orbit between cylinders. It is understood that me pressure can be maintained with more or fewer components or by incorporating any number of pressure regulating devices or manipulating the cycle timing.

[0084] In an exemplary embodiment, a valve is described for use with a concrete pump having a single material cylinder. The valve can be adapted to maintain pressure in the cylinder between intake and discharge cycles. In an exemplary embodiment, the valve includes a wing or shoulder, similar to the wings or shoulders 908a and 908b shown in Figs. 8a and 8b, positioned on either side of the inlet which is adapted to cover the cylinder and prevent a loss of pressure, thereby achieving constant pressure on the discharge outlet of the valve. This improvement may be incorporated to any conventional concrete pump, such as for example, the concrete pumps produced by, but not limited to, Schwing Bioset, Schwing, and Putzmeister. The following are incorporated herein by reference: Schwing America Inc, Electrical Schematic #10200527, BP 8800, serial number 108242; Schwing Operating Instructions BP 880 Article No. 10202001; Schwing America Inc, Parts List BP 880 CE Trailer Pump 108242; Schwing America Inc, Hydraulic Fittings High Pressure Hoses, Document # 699000, Rev. 05/17/02; and Schwing America Inc., Service Repair Instructions for The "Rock" Valve, Document #799000, Rev. 5/18/02. Selected pages of one or more of the above documents are attached herewith as Appendix A. The entire contents of the attached Appendix A is incorporated by reference herein.

[0085] In an exemplary embodiment, as illustrated in Figs. 8A and 8B, another valve 900 is illustrated which is similarly adapted to maintain a constant pressure during cycling between the intake and discharge steps of a first and second cylinder. Fig. 8A is a sectional view of the inlet of the valve 900. The valve consists of a body 902 connected to a shaft 904, on which the body swings between the first and second cylinder outlets (shown with dashed lines as 910 and 912). The inlet 906 to the valve 900 is adapted to cycle between the outlet 910 of the first cylinder and the outlet 912 of the second cylinder. The valve may include a shoulder portion (shown with the dashed line as 908a and 908b) which extends outward from the portion of the valve body 900 surrounding the valve inlet 906. The shoulder portions 908a and 908b may be fashioned in different shapes and sizes to achieve the result of preventing a loss of pressure during cycling of the valve.

[0086] Fig. 8B is a sectional view of the outlet of the valve 900. The outlet 914 can be a variety of different shapes, as shown here the outlet has a kidney shape, allowing for simplified alignment with the outlet 916. As can been seen by the in the two figures, the cylinder outlets 910 and 912 not collinear with the valve outlet 916.

[0087] In an exemplary embodiment, as illustrated in Fig. 9, the injection system 670 may include a concrete pump 566 which includes sequencing valve (not shown) selected from either a Rock Valve or a Big Rock Valve, produced by Schwing America, Inc., or a like valve. The injection system 670 may further include a diversion valve 672 connected to the pump 566 by pipe 570. The diversion valve 672 serves to delay the injection of the impactors 100 until the system is prepared to go "on-line." Diversion valve 672 diverts the steam of impactors via line 674 to the hopper 506, where the impactors may be resupplied to pump 566 via line 568. Optionally, line 674 may supply a stream of impactors to a particle processing step. Thus, in one exemplary embodiment, the injection system is operated and a continuous stream of the impactors is held in a continuous loop, wherein the impactors are supplied to the pump, discharge from the pump and are diverted to the hopper or processing step, and resupplied to the pump. Once the operator is ready to bring the injection system 670 "on-line", the diversion valve may be operated to supply impactors to the standpipe 504. In an exemplary embodiment, a check valve is employed between the pump and the standpipe to maintain a steady pressure in the standpipe. The injection system 670, by allowing the recirculation of impactors while "off line," will allow the concrete pump 566, or other pump, to be run independently of the drilling rig and be brought on line quickly. Another benefit of the injection system 670 is that the impactors, which will settle to the bottom of pipe 570 are constantly moving to prevent the impactors from settling and plugging wetted components.

[0088] In an exemplary embodiment, the pump 566 includes one or more pumps such as for example, one or more solids pumps, cavity pumps, positive displacement pumps, progressive cavity pumps, auger pumps, Moineau pumps and/or any combination thereof In several exemplary embodiments, one or more of the pumps that comprise the pump 566 are configured to pump dry or almost-dry solid material impactors. In several exemplary embodiments, one or more of the pumps that comprise the pump 566 are similar to pumps used to pump concrete, and/or to pump slurries. Examples of these types of pumps are manufactured by a variety of manufacturers, including but not limited to, Schwing Bioset, Schwing, and Putzmeister.

[0089] In an exemplary embodiment, impactors may be supplied to the concrete pump via means of a volumetric feeder. In another exemplary embodiment, impactors may be supplied to the concrete pump via means of a hopper. In another exemplary embodiment, impactors which are recovered from the wellbore are processed to remove drill cuttings, small particulate materials, and drilling fluids and may be then resupplied to the concrete pump 566.

[0090] In an exemplary embodiment, a particle injection system, which may include concrete pump 566, may also include one or more abrasion resistant or longer-wear components, such as for example, non-hardened pipe, heat-treated pipe, abrasion resistant single wall pipe, and twin wall pipe, each of which may optionally include chrome carbide insert ends or chrome carbide liners. Similarly, the particle injection system, which may include the concrete pump 566, may also include one or more ceramic, cast manganese or cast steel hardened elbow or bends having chrome carbide ends and/or chrome carbide lining. Exemplary particle injection systems which employ concrete pumps for the injection of solid material impactors for drilling purposes, are particularly suited for the use of reinforced elbows, joints, pipes and other components. Exemplary abrasion resistant parts suitable for use for the present application include those manufactured by Schwing America, Inc., Schwing Bioset, Inc., and Construction Forms, Inc. of Port Washington, Wisconsin. [0091] In other exemplary embodiments, a wear ring can be included at the interface between piping components, such as between the standpipe and the elbow. Preferably, the wear ring is manufactured from a highly wear and abrasion resistant material. In certain exemplary embodiments, the material has a higher hardness than the particulate matter. In certain embodiments, the wear ring is a wearable surface which can resist chipping or cracking in a highly abrasive environments.

[0092] In an exemplary embodiment, the pump 566 may be connected to one or more hydraulic or manual diversion or shut-off valves which are designed for concrete pumping applications. In another exemplary embodiment, the pump 566 may be connected to one or more diversion or shut-off valves which are designed for high pressure applications. In another exemplary embodiment, the pump 566 may be connected to one or more diversion or shut-off valves which are designed for pumping highly abrasive slurries.

[0093] In exemplary embodiments, the concrete or slurry pump discharge pressure may range from about 1500 pounds per square inch and in excess of about 6000 pounds per square inch, from about 1500 pounds per square inch to about 2500 pounds per square inch, from about 2500 pounds per square inch to about 6000 pounds per square inch, and all values between about 1500 pounds per square inch and about 6000 pounds per square inch. Higher pressures likely lead to increased drilling capabilities and greater penetration of impactors. Accordingly, in an optional embodiment, pump discharge pressures may range from about 1000 pounds per square inch to about 10,000 pounds per square inch. In an exemplary embodiment, the pump 566 includes one or more concrete or slurry pumps. However, instead of pumping concrete, the pump 566 pumps the impactors 100, and any associated fluids, during the operation of the particle injection system, as described above.

[0094] Contact surfaces of the devices and systems disclosed herein, such as the contacting surface of a transfer tube (also referred to herein as a rock valve or big rock valve) may include: steels hardened past raw material specifications, tool steels, specialty materials such as Inconel®, Stellite®, titanium, and alloys having one of nickel, silver, bronze, molybdenum, and copper, and combinations thereof. Composites having an abrasion resistant material and a softer filler, such as tungsten carbide, nickel, copper, silver, alloyed metals, abrasive cloth, layered materials and combinations thereof. Coatings applied with a spray, fused thereon, cast, welded, brazed, burnished, or splattered. Super abrasive materials, such as cubic boron nitride, diamond like materials, diamond silicon carbide, aluminum oxide, and combinations thereof. Materials harder than steel that are allied by chemical vapor deposition technology. Elastomeric, and polymeric materials, such as urethane, and others including filled elastomers and polymers, including layered. Reinforced materials, including fibers, stands, or chopped materials.

[0095] In an exemplary embodiment, the pump 566 includes one or more concrete or slurry pumps manufactured by Schwing America Inc. of St. Paul, Minnesota or Schwing Bioset, Inc. of Somerset, Wisconsin. In an exemplary embodiment, the pump 566 includes one or more concrete pumps manufactured by Schwing America, Inc. of St. Paul, Minnesota, and at least one of the one or more concrete pumps includes a Rock Valve sequencing valve and/or a Big Rock Valve sequencing valve, which are manufactured by Schwing America, Inc. of St. Paul, Minnesota. Instead of pumping concrete, however, the pump 566 pumps the solid material impactors 100, and any associated fluids, during the operation of the particle injection system, as described above. In some exemplary embodiments, the concrete pump 566 can be used to pump dry particulate materials, and in other exemplary embodiments, the concrete pump 566 can be used to pump a slurry which may include particulate materials. In certain exemplary embodiments, the concrete pump 566 is used to introduce a particulate slurry into a wellbore.

[0096] Other pump manufacturers producing concrete or slurry pumps which may also be used to supply particulate material according to the present application include, but are not limited to, one or more of the pumps manufactured by any of the following manufactures: Putzmeister AG (Germany), Putzmeister America, Inc. (Sturtevant, Wisconsin); Multiquip/Mayco (Carson, CA); Reed Concrete Pumps (Chino, CA); Allentown Equipment (Allentown, PA) and Olin Engineering (CA). It is understood that other concrete and slurry pumps manufactured by other manufacturers not listed herein may also be used to pump particulate materials and slurries which include particulate materials. Exemplary concrete pumps may include one or more sequenced material cylinder for pumping particulate materials. Other exemplary pumps include any pump capable of taking a slurry at atmospheric pressure and discharging the slurry at a higher pressure. In certain exemplary embodiments, the cylinders may be hydraulically driven.

[0097] In an exemplary embodiment, the pump 566 is a positive displacement concrete pump which includes a sequencing valve having a transfer tube and at least one material cylinder. The sequencing valve may be a Rock Valve or a Big Rock Valve, produced by Schwing America, or a Rock Valve produced by Schwing Bioset, Inc, or a like sequencing valve. Other valves may also be employed to sequence between the intake and discharge of materials, such as for example, an S-tube valve, a C-tube valve, ball valves, or gate valves.

[0098] A perspective partially exploded view of a portion of an example of a concrete pump 322 is depicted in Fig. 11. The concrete pump 322 illustrated comprises a housing 344 shown with a semi-circular cross section, however enclosures having other shapes can also be used. To illustrate the pump 322 internal components, an upper enclosure is not shown in this illustration. It is well within the capabilities of those skilled in the art to implement a proper upper enclosure. The housing is portrayed having therein a first cylinder 346 and second cylinder 348, the cylinders (346, 348) both aligned substantially parallel with the elongate length of the concrete pump 322. A substantially planar forward housing 345 is provided within the housing 344 transverse to the cylinders (346, 348) and defines a terminal end of the cylinders (346, 348). A rearward housing 349, aligned substantially parallel with the forward housing 345 comprises a housing 344 end opposite the forward housing 345. For the purposes of discussion herein, the term "aft" refers to a direction towards the rearward housing 349, and forward refers to a direction towards the forward housing 345. A first opening 354 is formed through the forward housing 345 that registers with the first cylinder 346. A second opening 356 also formed through the forward housing 345 registers with the second cylinder 348. A first piston 350 is illustrated in dashed outline within the first cylinder 348 shown having a connecting rod 351 affixed to its aft end. A second piston 352 is shown, also in dashed outline, in the second cylinder 348 having a connecting rod 353 affixed to its aft end.

[0099] The housing 344 sides and lower portion extend forward past the forward housing wall 345 and have a flanged surface 355 formed on the forward terminal end. An end cover 360 is shown in exploded view away from the housing 344, when the concrete pump 322 is assembled the end cover 360 mates onto the flanged surface 355. A mixing feed chamber 358 is defined between the forward housing wall 345 and end cover 360 and bounded on its lower end by the housing 344 sides and lower portion that extend past the forward housing wall 345. A pump discharge line 362 connected to the end cover 360 extends forward from the concrete pump 322 and is in fluid communication with one of the openings (354, 356) by a passage 361 formed through the end cover 360. [00100] In one example of concrete pump 322 operation, a slurry of impactors 359 and fluid 357 are fed into the mixing feed chamber 358. The mixing feed chamber 358 is typically at approximately ambient pressure. The pistons (350, 352) are reciprocated within the cylinders (346, 348) and draw the slurry into a cylinder (346, 348) when the associated piston is moving in an aft direction (suction stroke) and then pressurize the slurry drawn into the cylinder when the piston is moved forward (pressurization or discharge stroke). As described below, a valve system selectively communicates each opening (354, 356) with the mixing feed chamber 358 when the respective piston (350, 352) is reciprocating aft. The valve then selectively seals the respective cylinder (346, 348) from the mixing feed chamber 358 when the associated piston (350, 352) changes its stroke from aft to forward and fluidly couples the opening (354, 356) with the pump discharge 361. When the piston (350, 352) moves forward in the cylinder (346, 348) impactor fluid slurry in the cylinder (346, 348) is pressurized and discharged from the pump 322 through the pump discharge 361. In the example shown in Fig. 11, arrow A₁ demonstrates the piston 350 is moving in the aft direction and draws impactor fluid slurry into the cylinder 346 via the opening 354. Similarly, the piston 356 is moving forward as depicted by arrow A₂ and pressurizing impactor fluid slurry in the cylinder 348. The pressurized impactor fluid slurry is discharged through the opening 356 to the pump discharge 361 through a selector valve (not shown). Optionally, an impactor fluid slurry can be injected into the cylinders (346, 348) through a passage (not shown) formed through the pistons (350, 352) and piston connection rods (351, 353). Power for reciprocating the pistons (350, 352) is provided through the piston connection rods (351, 353) and may be from hydraulic power, mechanical power, or electrical power. Yet further optionally, a perturbation device may be included within the mixing feed chamber 358 for mixing the impactors and fluid therein. Examples include mechanical agitators (such as an inserted mixer or a blade on the transfer tube) and nozzles ejecting a fluid stream directed at or within the impactor fluid slurry, the fluid can be a gas or liquid.

[00101] Referring again to Fig. 11, an optional chamfer 363 is illustrated extending from the piston 351 forward end. Having a tapered or beveled cross section, the chamfer 363 may direct impactors 359 and other particles away from the gap between the piston 351 outer periphery and cylinder 346 inner circumference to prevent trapped particles in the gap that may damage either the piston 351 or cylinder 346. The chamfer 363 may be on a portion of or the entire piston 351 circumference. [00102] Figs. 12a - 12c illustrate an embodiment of a selector valve assembly 364 that selectively seals the openings (354, 356) of the cylinders (346, 348) from the feed mixing chamber 358 and selectively communicates the openings (354, 356) of the cylinders (346, 348) with the slurry discharge line 324 (Fig. 10). In the embodiment of Figs. 12a - 12c the selector valve assembly 364 comprises a first reciprocating valve 372 associated with the first opening 354 and a second reciprocating valve 376 associated with the second opening 356. The selector valve assembly 364 uses a modified end cover 360a having a first discharge 368 and a second discharge 370. The first and second discharge (368, 370) both connect to the slurry discharge line 324 (Fig. 10). Discharge flow passages (374, 378) are formed through each body (380, 381) and are registerable with respective openings (354, 356) and the discharge flow passages (374, 378) to provide fluid communication therebetween.

[00103] As seen in an overhead view in Fig. 12b, each valve (372, 376) comprises a body (380, 381) having on its upper end a sloped inlet ramp (373, 377) having an opening in communication with the suction opening of the cylinder, the embodiment shown comprises a curved lower surface. As shown in Fig. 12b, the first reciprocating valve 372 is positioned to allow communication between the mixing feed chamber 358 and the first opening 354. The inlet ramp 373 on the body 380 is aligned with the opening 354 and configured to receive impactor fluid slurry therein and direct it into the opening 354. Arrow As represents impactor fluid slurry flow over the inlet ramp 373 and into the opening 354. Coupling attachments (375, 379) shown in Figs. 12a and 12c are provided on the lower end of each body (380, 381) for connecting the valves (372, 376) to an actuation source for reciprocatingly actuating the valves (372, 376). In the embodiment of Figs 12a - 12c the valves (372, 376) vertically shuttle between a suction position (communicating the openings (354, 356) with the mixing feed chamber 358) and a discharge position (communicating the openings (354, 356) with the discharge flow passages (374, 378) and the first and second discharges (368, 370). The shuttling may be alternating and 180° out of phase, i.e. one valve (372, 376) in the suction position and the other in the discharge. Optionally the valves (372, 376) may be synchronous, i.e. operating at the same position simultaneously, or out of phase by less than 180°. To facilitate the timing issues when the valves (372, 376) are out of phase by less than 180°, the piston (348, 350) stroke velocity may be adjusted so their suction stroke time differs from the pressurization stroke time. This adjustment creates a piston (350, 352) sequence where both can be discharging at the same time, although at different portions of the discharge stroke, but generally not in the suction mode at the same time. Accordingly, the valve operation sequence provides a method to avoid pressure communication between the mixing feed chamber 358 and the discharge line 361. Optionally, the bodies (380, 381) can be affixed to one another or combined in a uni-body assembly. Moreover, the reciprocating action of the bodies (380, 381) can be in a non-vertical alignment. The mixing feed chamber and other components may be combined or eliminated.

[00104] Figs. 13a - 13h illustrate another embodiment of a selector valve assembly 364a in various operational modes. Figs. 13a, c, e, g are frontal views and Figs. 13 b, d, f, h are perspective views. In this embodiment the selector valve assembly 364a comprises a first and a second transfer tube (382, 384) both transversely disposed in the mixing feed chamber 358. The transfer tubes (382, 384) are rotatingly coupled to pivot pins (383, 385) that are affixed to the end cover 360, the forward housing wall 345, or both. The transfer tubes (382, 384) are annular members having an entrance selectively registerable with respective first and second openings (354, 356). Each transfer tube (382, 384) has an exit on an end opposite the entrance respectively in fluid communication with the first and second discharges (368, 370) formed through the end cover 360. Pivoting the transfer tubes (382, 384) with respect to the pivot pins (383, 385) laterally orbits the transfer tubes (382, 384) along a curved path on the forward surface of the forward housing wall 345. Selective lateral orbiting registers the transfer tubes (382, 384) with their respective openings (354, 356) thereby fluidly communicating the openings (354, 356) with respective discharges (368, 370) through the transfer tube (382, 384). In Figs. 13a - 13h the end cover 360 is illustrated translucent to better demonstrate features of the selector valve assembly 364a. The outer periphery of the transfer tubes (382, 384) is substantially circular at its entrance proximate to the forward housing wall 345 and expands to a generally oval configuration at its exit proximate to the end cover 360. The elongate length of the oval exit is greater than the diameter of the circular entrance.

[00105] With reference now to Figs. 13a and 13b, the first transfer tube 382 is pivoted into a suction configuration with its entrance out of registration with the opening 354. The pivoting rotational movement is illustrated by curved arrow P$. The transfer tube 382 entrance seals against the forward facing surface of the forward housing wall 345 and thus is not in pressure communication with the mixing feed chamber 358. Without the transfer tube 382 sealing and isolating the opening 354 from the mixing feed chamber 358, the opening 354 is in communication with the mixing feed chamber 358. Combining the communication between the chamber 358 and the opening 354 with a suction stroke on the piston 350 (Fig. 11) draws impactor fluid slurry into the cylinder 346 as illustrated by arrow A_IN.

[00106] Also in Figs. 13a and 13b, the second transfer tube 384 is shown pivoted about its pivot pin 385 having its entrance aligned with the opening 356. This alignment combined with a discharge stroke of the piston 352 (Fig. 11) discharges impactor fluid slurry through the transfer tube 384 and discharge 370 as illustrated by arrow A_OUT. In Figs. 13c and 13d the first transfer tube 382 has been pivoted (as illustrated by curved arrow P_D) registering its entrance with the opening 354. Positioning the sealing face of the first transfer tube 382 around the opening 354 sealingly isolates the opening 354 from the mixing feed chamber 358, thereby isolating the first transfer tube 384 and discharge 370 from ambient pressure. Combining this alignment with the piston 350 in a discharge stroke discharges impactor fluid slurry through the transfer tube 382 and the first discharge 368. In Fig. 13c and 13d, pressurized impactor fluid slurry may be discharged from both the first and second transfer tubes (382, 384) for a period of time. As described above, one way to accomplish this is by having a suction stroke time different from the discharge stroke time. The pressurized impactor fluid slurry discharged from the first and second discharge (368, 370) is directable to the slurry discharge line 324 (Fig. 10). In one example of use, the first and second piston advance in sequence to provide a combined forward velocity that is near constant, resulting in a near constant pressure and impactor discharge rate.

[00107] Pivoting the transfer tubes (382, 384) about their respective pivot pins (383, 385) can be accomplished via hydraulic power, electrical power, or mechanical means. It is within the capabilities of those skilled in the art to apply a pivoting force synchronized as described herein. As illustrated in Figs. 13a and 13c, the outwardly flared exit of the first and second transfer tubes (382, 384) remains in fluid communication with the respective discharge (368, 370) during transfer tube (382, 384) pivoting.

[00108] Figs. 13e and 13f represent the first transfer tube 382 and associated cylinder 346 and piston 350 in a discharge stroke whereas the second transfer tube 384 is pivoted into a suction mode (as illustrated by curved arrow Ps) allowing communication between the mixing feed chamber 358 and the entrance 356. Arrows A_IN and A_OUT respectively represent impactor fluid slurry suction into the opening 356 and pressurized impactor slurry discharge from the first discharge 368. Pivoting the second transfer tube 384 into alignment with the entrance 356 (as illustrated by curved arrow P_D) is depicted in Figs. 13g and 13h. Pressurized impactor fluid slurry discharge is shown by arrow A_OUT. An example of a transfer tube suitable for use as disclosed herein is a "rock valve" obtainable from Schwing America Inc., 5900 Centerville Road, St. Paul, MN 55127, 651429-0999, www.schwing.com.

[00109] Another example of a selector valve assembly 364b is provided in perspective view in Fig. 14. In this embodiment, the selector valve assembly 364b comprises a kidney shaped shroud 365, the shroud 365 is substantially planar and disposed parallel with the forward surface of the forward housing wall 345. An annular transfer tube 366 extends from the forward surface of the shroud 365 and affixed to the shroud 365 in alignment with an aperture 369 formed through the shroud 365. The valve assembly 364b is pivotmgly affixed to a pivot pin 367 connected to the forward housing wall 345 thereby providing pivoting motion of the valve assembly 364b adjacent the forward housing wall 345. As shown the valve assembly 364b is situated to transfer pressurized impactor and fluid slurry from the discharge stroke of the first piston 350 and cylinder 346 via the first opening. When pivoting the assembly 364b to receive discharge slurry from the second opening 354, the shroud 365 seals the first opening 356 from the ambient pressure mixing feed chamber 358 before the transfer tube 366 registers with the second opening 356 thereby sealing the transfer tube 366 from the mixing feed chamber 358 and preventing the discharge circuit from exposure to ambient pressure conditions.

[00110] An optional seal assembly 388 for sealing between the exit of a transfer tube (382, 384) and the end cover 360 is shown in an end view in Fig. 15, A representation of the transfer tube (382, 384) axis Ax is provided for reference. The seal assembly 388 comprises a seal body 390, a wiper base 391, and a wiper edge 392 extending from the base 391. As shown in partial sectional view in Fig. 16, the wiper edge 392 has a beveled cross section and extends outward from the seal assembly 388 outer periphery. An optional elastomer o-ring 394 is provided between the wiper base 391 and the seal body 390 outer periphery. A representation of the transfer tube (382, 384) axis Ax is provided for reference. The wiper edge 392 includes a planar surface on the side disposed adjacent the end cover 360 with the bevel on the other side. When pivoting the transfer tube (382, 384) as previously described the seal assembly 388 may encounter impactors 347 and other solid material on the mating surface of the end cover 360. When pivoting the transfer tube (382, 384), in the back and forth direction represented by the double headed arrow P_M, the beveled wiper edge 392 can scrape away solid particles. This avoids wedging particles between the seal body 390 and the end cover 360 surface thereby preventing damage of either the seal assembly 388 or end cover 360 surface due to scratching or gouging by the particles. A force generating means, such as a spring 393 is shown for energizing the wiper base 391 against the end cover 360 and a potentially separate sealing means between the wiper base 391 and the transfer tube (382, 384).

[00111] An optional seal 369 coupled with an end of a transfer tube 366a is illustrated in perspective view in Fig. 17. In this embodiment, a viscous fluid, such as a lubricant, is delivered to a plenum 386 formed in the free end of the seal 369. Delivering a lubricating substance through the seal provides a self correcting/replenishing seal which may be used in circuits for pumping low viscosity slurries and at high pressures. As shown in a cross sectional view in Fig. 18, a lubricating fluid is delivered to the plenum 386 via a lubricant feed line 371 connected to the plenum 386. Lubricant flow, represented by arrow A_L, passes through the plenum 386 and into a gap 387 between the seal 369 and the end plate 360. The lubricating fluid may be pumped from a reservoir and charged to a high pressure. The lubricant can be delivered to the seal during static conditions to provide motion starting lubrication as well as a sealing function. It should be pointed out however the seal assembly described herein is not limited to the transfer tube or end plate, but is applicable to other contacting surfaces.

[00112] Optionally included with a seal assembly disposed between the transfer tube and the end cover is an anti-extrusion member. The anti-extrusion member may circumscribe the seal assembly and be combined with an O-ring. Yet further optionally, the backup O-rings may be included with all sealing components for the device and system disclosed herein.

Example 1

[00113] Impactors were circulated in the system for 75 minutes with an impactor flow rate of about 15 gallons per minute, a hopper fill rate of 165 to 190 gallons per minute, with a total flow rate of 360 to 370 gallons per minute, a pump discharge pressure between 1000 pounds per square inch to 2500 pounds per square inch. A Schwing BP8800 was used for pressurizing impactor and fluid slurry.

Example 2 [00114] Impactors were circulated in the system for 94 minutes with an impactor flow rate of about 15 gallons per minute, a hopper fill rate of 100 to 160 gallons per minute, with a total flow rate of 340 to 375 gallons per minute, a pump discharge pressure between 1000 pounds per square inch to 2500 pounds per square inch. A Schwing BP8800 was used for pressurizing impactor and fluid slurry.

[00115] It is understood that variations may be made in the foregoing without departing from the scope of the disclosure.

[00116] Any spatial references such as, for example, "upper," "lower," "above," "below," "radial," "axial," "between," "vertical," "horizontal," "angular," "upward," "downward," "side-to-side," "left-to-right," "right-to-left," "top-to-bottom," "bottom-to-top," etc., are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above.

[00117] As used herein, the terms "about" and "approximately" are understood to refer to values which are within 5% of the number being modified by the terms.

[00118] In several exemplary embodiments, one or more of the operational steps in each embodiment may be omitted. Moreover, in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. Moreover, one or more of the above-described embodiments and/or variations may be combined in whole or in part with any one or more of the other above-described embodiments and/or variations.

[00119] Although several exemplary embodiments have been described in detail above, the embodiments described are exemplary only and are not limiting, and those skilled in the art will readily appreciate that many other modifications, changes and/or substitutions are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the present disclosure. Accordingly, all such modifications, changes and/or substitutions are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.

Claims

ClaimsWhat is claimed is:

1. A method of injecting an impactor and fluid slurry into a high pressure drilling fluid stream, the method comprising: pressurizing the impactor and fluid slurry in a concrete pump to a set pressure value, wherein the set pressure value is approximately the drilling fluid stream pressure value and wherein the set pressure exceeds ambient pressure; discharging the pressurized impactor and fluid slurry from the concrete pump to a slurry discharge line; maintaining the pressure in the slurry discharge line substantially at the set pressure; and injecting the pressurized impactor and fluid slurry into the slurry discharge line to the high pressure drilling fluid stream to thereby form a drilling fluid stream having impactors.

2. The method of claim 1 , the concrete pump having a first and a second cylinder each having an inlet, a first and second piston reciprocatingly disposed in the first and second cylinder respectively, a mixing feed chamber in selective communication with each inlet, the mixing feed chamber at substantially ambient pressure, wherein each inlet is selectively in fluid communication with the slurry discharge line.

3. The method of claim 2, wherein the concrete pump further comprises a first transfer tube in selective communication between the first inlet and the first cylinder inlet and the discharge circuit and a second transfer tube in selective communication between the second inlet and the second cylinder inlet and the slurry discharge line, the method further comprising synchronizing the communication between the inlet on the first cylinder and the first transfer tube when the first piston is in a discharge stroke, thereby isolating the slurry discharge line from the mixing feed chamber.

4. The method of claim 3 further comprising synchronizing the communication between the inlet on the second cylinder and the second transfer tube when the second piston is in a discharge stroke, thereby isolating the slurry discharge line from the mixing feed chamber.

5. The method of claim 2, wherein the concrete pump further comprises a transfer tube having an entrance selectively disposed in communication between the inlet on the first cylinder and the slurry discharge line when the first piston is in a discharge stroke and in communication between the inlet on the second cylinder and the discharge line when the second piston is in a discharge stroke, the transfer tube further having a shroud circumscribing the transfer tube entrance, the shroud blocking each respective inlet from the mixing feed chamber as the transfer tube is disposed into communication with the respective inlet thereby isolating the slurry discharge line from the mixing feed chamber.

6. The method of claim 1 further comprising allowing flow in the slurry discharge line in a single direction from the concrete pump discharge to the high pressure drilling fluid stream.

7. The method of claim 6, wherein the method of allowing flow in a single direction comprises inserting a one way valve in the slurry discharge line.

8. The method of claim 1 further comprising directing the drilling fluid stream having impactors to a drilling string, discharging the drilling fluid stream having impactors from the drilling string, and boring through the earth.

9. The method of claim 1, wherein the slurry discharge line pressure is maintained from about 1500 pounds per square inch to about 2500 pounds per square inch.

10. The method of claim 1, wherein the slurry discharge pressure line is maintained from about 2500 pounds per square inch to about 6000 pounds per square inch.

11. A fluid system for subterranean excavating comprising: a pressurized drilling fluid line having high pressure drilling fluid therein; a slurry discharge line having a first end and a second end, the slurry discharge line connected on its first end to the drilling fluid line; a concrete pump comprising a cylinder having an opening, a piston reciprocatingly disposed in the cylinder, a mixing feed chamber having a fluid and impactor slurry therein, the mixing feed chamber in selective fluid communication with the cylinder through the opening as the piston is reciprocating away from the opening, a transfer tube moveable into selective registration between the cylinder opening and the slurry discharge line second end as the piston is reciprocating towards the opening, and a pressure isolation member sealingly disposed between the mixing feed chamber and the opening as the transfer tube is moving into selective registration with the opening, thereby isolating the slurry discharge line from the mixing feed chamber.

12. The fluid system of claim 11, wherein the concrete pump further comprises a second cylinder having an opening and a second piston reciprocatingly disposed therein, wherein the transfer tube is selectively registerable between the second cylinder opening and the slurry discharge line as the second piston reciprocatingly moves towards the opening.

13. The fluid system of claim 11, wherein the concrete pump further comprises a second cylinder having an opening and a second piston reciprocatingly disposed therein and a second transfer tube, wherein the second transfer tube is selectively registerable between the second cylinder opening and the slurry discharge line as the second piston reciprocatingly moves towards the opening.

14. The fluid system of claim 13, wherein the transfer tube laterally moves in and out of registration with the opening along a first line, and the second transfer tube laterally moves in and out of registration with the second opening along a second line.

15. The fluid system of claim 13, wherein the transfer tube laterally moves in and out of registration with the opening along a first orbital path, and the second transfer tube laterally moves in and out of registration with the second opening along a second orbital path.

16. The fluid system of claim 11, wherein the slurry discharge line is maintained at a set pressure suitable to inject the impactor and fluid slurry into the high pressure drilling fluid stream.

17. The fluid system of claim 11, wherein the slurry discharge line is maintained at a pressure of about 1500 pounds per square inch to about 2500 pounds per square inch.

18. The fluid system of claim 11, wherein the slurry discharge line is maintained at a pressure of about 2500 pounds per square inch to about 6000 pounds per square inch.

19. The fluid system of claim 11, further comprising a seal provided on an end of the transfer tube, the seal comprising, a seal body, a bevel radially extending from the seal body past transfer tube outer periphery, and a resilient member between the seal body and the transfer tube.

20. The fluid system of claim 11, further comprising a seal provided on an end of the transfer tube, the seal comprising, a seal body, and a lubricant injection line communicating through the seal body.

21. The fluid system of claim 11, further comprising a chamfered profile extending coaxially away from a portion of the piston outer periphery and on the end of the piston proximate to the opening.

22. A method of earth boring comprising: pressurizing an impactor and fluid slurry in a concrete pump to a set pressure that exceeds ambient pressure; discharging the pressurized impactor and fluid slurry from the concrete pump to a discharge circuit; maintaining the pressure in the discharge circuit at substantially the set pressure; directing the pressurized impactor and fluid slurry from the discharge circuit to a drill string; and discharging the impactor and fluid slurry from the drill string and boring through the earth.

23. The method of claim 22, the concrete pump having a first and a second cylinder each having an inlet, a first and second piston reciprocatingly disposed in the first and second cylinder respectively, a mixing feed chamber communicatable with each inlet, the mixing feed chamber at substantially ambient pressure, wherein each inlet is selectively in fluid communication with the discharge circuit.

24. The method of claim 23, wherein the concrete pump further comprises a first transfer tube in selective communication between the first inlet and the first cylinder inlet and the discharge circuit and a second transfer tube in selective communication between the second inlet and the second cylinder inlet and the discharge circuit, the method further comprising synchronizing the communication between the inlet on the first cylinder and the first transfer tube when the first piston is in a discharge stroke, thereby isolating the discharge circuit from the mixing feed chamber.

25. The method of claim 24 further comprising synchronizing the communication between the inlet on the second cylinder and the second transfer tube when the second piston is in a discharge stroke, thereby isolating the discharge circuit from the mixing feed chamber.

26. The method of claim 22, wherein the concrete pump further comprises a transfer tube having an entrance selectively disposed in communication between the inlet on the first cylinder and the discharge circuit when the first piston is in a discharge stroke and in communication between the inlet on the second cylinder and the discbarge circuit when the second piston is in a discharge stroke, the transfer tube further having a shroud circumscribing the entrance, the shroud blocking each inlet from the mixing feed chamber as the transfer tube is disposed into communication with the inlet thereby isolating the discharge circuit from the mixing feed chamber.

27. The method of claim 22, wherein the discharge circuit comprises a line having fluid pressurized by a second pressure source and a slurry line communicating the pressurized impactor and fluid slurry to the line, the method further comprising allowing flow in the slurry line in a single direction from the first pressure source discharge to the line.

28. The method of claim 27, wherein the method of allowing flow in a single direction comprises inserting a one way valve in the slurry line.