US 3347315 A
Descripción (El texto procesado por OCR puede contener errores)
Oct. 17, 1967 Filed April 29, 1965 C. P. LANMON ll METHODS FOR WELL COMPLETION 2 Sheets-Sheet 1 C P an/77 of? INVENTOR.
Oct. 17, 1967 C; R ANMN 3,347,315
METHODS FOR WELL COMPLETION Filed April 29, 1965 2 Sheets-Sheet 2 I l QQ y 153B i 7i 7 [NVE/WOR.
United States Patent O 3,347,315 METHODS FOR WELL COMPLETION C. P. Lanmon II, Friendswood, Tex., assignor, by mesne assignments, to Schlumberger Technology Corporation, Houston, Tex., a corporation of Texas Filed Apr. 29, 1965, Ser. No. 451,857 5 Claims. (Cl. 166-23) ABSTRACT OF THE DISCLOSURE Thisapplication discloses methods for consolidating incompetent earth formations surrounding a cased well bore and providing unobstructed fluid communication therewith. More particularly, the disclosed methods are directed toward consolidating -a portion of an incompetent earth formation adjacent to a cased well bore to preclude the subsequent displacement of loose particles of formation materials as well as to provide relatively unobstructed fluid communication therewith. These methods are accomplished by rst injecting a suitable consolidating agent or agents into the particular formation being completed. Then, once it is believed that the injected portion of the formation has suciently iirmed, a perforation is made through the casing and cement into the irmed formation portion to provide a clean unobstructed fluid-communication path thereto.
Accordingly, as will subsequently become more apparent, this invention relates to methods for completing wells; and, more particularly, to methods for inhibiting the production of sand from unconsolidated or incompetent subsurface formations.
The present trend in well completion techniques is `to rely upon only one or, at most, a very few perforations at each of carefully selected points in -a Well rather than indiscriminately scattering a large number of perforations along a wide interval. Where such perforations are made in a particularly loose or unconsolidated formation, sand particles and the like, will, however, be displaced into the well bore as connate fluids are produced from the formation. Thus, unless preventative measures are taken, these sand particles will either settle out so as to eventually till the Well bore or be carried to the surface by the produced fluids and severely damage production equipment. Moreover, with only a few perforations aifording limited entry through the casing into the formation, the production will be severely limited should any of these perforations become plugged.
. Accordingly, to solve this problem, apparatus and methods have been devised whereby as soon as a loose formation is perfor-ated, a suitable bonding or consolidating agent is injected through the perforation into the formation where, in time, it will react and harden. These agents, or so-called plastics generally coat the sand grains and thereby cement them together. Although it will depend upon the particular agents employed, the pore spaces between adjacent particles are left open in one way or another so as to provide permeability. Thus, a portion of the formation surrounding the perforation is consolidated to serve as a porous support to prevent loose sand particles from entering the perforation as connate fluids are produced from the formation.
Typical of such treating agents, apparatus and methods are those disclosed in Patent No. 3,153,449 granted to Maurice P. Lebourg and No. 3,174,547 granted to Roger Q. Fields. As described in those patents, a perforating and injecting tool is positioned adjacent a formation that is believed to be unconsolidated. An extendible wall-engaging member is operated to shift the tool toward one wall of the casing and sealingly engage a sealing member on the opposite wall to isolate a portion of the well bore from the Well control tiuids. A perforator, such as a shaped charge, is then actuated to produce a perforation through this isolated portion into the adjacent earth formation. Thereafter, a bonding agent is ejected from a cylinder in the tool by a displacing piston and injected through the perforation into the formation.
The present invention is intended to provide new and improved methods for completing unconsolidated earth formations where the formations are rst consolidated prior to completion. Then, once the formation is consolidated, it is completed and debris is removed from the perforation in the consolidated portion of the formation. This debris has been found to include particles of the casing and cement as well as residue from the shaped charge. By removing this low-permeability debris, the surfaces through which connate iluids must flow will be cleaned to greatly increase production ow rates.
Accordingly, it is an object of the present invention to provide new and improved methods for consolidating an incompetent earth formation and providing a fluid passage therein that is free of such objectionable lowpermeability debris.
This and other objects of the present invention are provided by rst isolating a surface of an unconsolidated earth formation from the well control uids in a well bore; perforating thru the isolated surface into the formation; injecting a formation-consolidating agent into the formation under sufficient pressure to overcome the effects of debris; and, when the formation-consolidating agent is calculated to have firmed, perforating through the isolated surfaces into the treating portion of the formation to provide a fluid passage into the stabilized formation and to remove the debris from the passage.
The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in. which:
FIG. 1 is a View depicting a well completion tool within a well bore and in position to practice the present invention;
FIG. 2 is an elevational View, partially in cross-section, of Ia portion of the tool depicted in FIG. l; and
FIGS. 3-5 are views depicting in sequence the apparatus of FIG. 1 performing the methods of the present invention.
Turning now to FIG. l, a well completion tool 10 arranged to practice the methods of the present invention is shown suspended from a multi-conductor cable 11 in a casing 12 secured within a borehole 13 by a column of cement 14. The cable 11 is spooled from a winch (not shown) at the earths surface, with some of its conductors being arranged for selective connection to a power source (not shown) and others being connected to indicating-and-recording means (not shown) at the surface of the ground.
The well completion tool 10 is comprised of an elongated body which, to facilitate manufacture and assembly, may be arranged to include upper and lower sections 15 and 16 that are tandemly connected above and below an intermediate section 17 having longitudinally spaced, annular, sealing means 18 and 19 on one side thereof and extendible wall-engaging means 20 on its opposite side.
The upper section 15 encloses a hydraulic system (not shown) for selectively actuating the extendible wall-engaging means 2G. This hydraulic system may, for example,
be of the type illustrated in Patent No. 3,011,554, granted to Robert Desbrandes which utilizes the hydrostatic pressure of the well control uids 21 to develop an increased pressure in the system for selectively actuating the wallengaging means 20. Thus, upon command from the surface, the wall-engaging means will be extended against one side of the casing 12 to shift the tool 10 laterally and sealingly engage the sealing means 18 and 19 against the opposite side of the casing. Then, when it is desired to retrieve the tool 10, the hydraulic pressure in the system is relieved and the wall-engaging means 20 are retracted.
The hydraulically actuated wall-engaging means 20 are comprised of one or more extendible pistons 22 that support a back-up shoe 23 that is normally held in a retracted position against the setcion 17 by springs 24. The pistons 22 are sealingly received within hydraulic cylinders (not shown) that are connected to the hydraulic system. Thus, whenever the hydraulic system is activated from the surface, the developed hydraulic pressure will urge the pistons 22 outwardly to extend the back-up shoe 23 against the casing 12. Inasmuch as the particular details of the hydraulic system and wall-engaging means 20 are note necessary for fully understanding the present invention, they have been shown only schematically in FIG. 1.
Fluid discharge means are generally housed in the intermediate section 17 and include a pair of lateral chambers 25 and 26 within the section that are each open at one end, with the annular sealing means 18 and 19 being mounted around the open ends of these cham-bers to provide central openings 27 and 28. The lower chamber 26 is connected to a fluid passage 29; and thin-walled closure members 30 and 31 are mounted in the chamber on each side of the open upper end of the passage 29 to block the central opening 28 and the rearward portion of the chamber. A shaped charge 32 is received in the rearward portion of the chamber 26 and faces the closure members 30 and 31 so that, upon detonation, the perforating jet will puncture the closure members and be directed through the central opening 28.
In a similar manner, the upper chamber 25 is connected by a fluid passage 33 to an enclosed low-pressure or atmospheric chamber 34 in the intermediate section 17. Thin-walled closure members 35 and 36 are mounted in the upper chamber 25 on each side of the open lower end of the passage 23 to block the central opening 27 of the sealing means 18 and the rearward portion of the chamber. A shaped charge 37 is disposed in the rear of the upper chamber 25 and directed toward the closure members 35 and 36 so that, upon detonation, the perforating jet will pierce the closure members and be directed through the central openings 27. Suitable electrically responsive igniter means 38 and 39 (FIG. 2*), that are ignitable from the surface of the earth via conductors in the cable 11, are connected to the shaped charge 32 and 37.
It will be realized that when the lower shaped charge 32 is detonated to puncture the closure members 30 and 31 and produce a perforation into an adjacent earth formation, lluid communication will be established from the fluid passage 29 through the central opening 28 and into the resultant perforation. Similarly, whenever the other shaped charge 37 is detonated, the closure members 35 and 36 will be pierced and fluid communication will be established from the resultant perforation through the central opening 27 and into the low-pressure chamber 34.
A treating agent cylinder 40 is formed in the lower section 16 and connected by a centrally located passage 41 to a normally-open valve 42 (such as that shown at 105 in the above-mentioned Desbrandes patent) connected to fluid passage 29. The treating agent injector 43 for the cylinder 40 is comprised of a slidable, hollow cylinder 44 that has a closed lower end 45 and is telescoped over a piston 46 secured through an elongated coaxial rod 47 to the upper end of the treating agent cylinder 40 and slidably received in the treating agent cylinder. An annular piston 48 secured to the upper end of the slidable cylinder 44 is fluidly sealed by O-rings 49 and 50 to the inner wall of the treating agent cylinder 40 and elongated rod 47, respectively, to isolate the treating agents in the cylinder 40 above the annular piston. An O-ring 51 tluidly seals the fixed piston 46 to the inner wall of the hollow cylinder 44 to provide an enclosed low-pressure or atmospheric chamber 52 therein below the fixed piston. A port 53 is provided in the wall of the hollow cylinder 44 to admit Well control fluids 21 into the space 54 below the annular piston 48 and above the Xed piston 46.
The treating agent cylinder is divided into separate fluid-tight chambers 55-57 by spaced, floating pistons 58 and 59 that are each uidly sealed between the elongated rod 47 and inner wall of the cylinder 40. As will be subsequently explained, valves 60 and 61 (such as those in FIG. 3 of the Fields patent) in the annular floating pistons S8 and 59 remain closed to segregate the treating agents in the chambers 55-57 until each piston 58 and 59 has reached its upper limit of travel. A flow restrictor 62 is placed in series with the valve 60 to regulate the flow of treating agents from the intermediate and lower chambers S6 and 57.
It will be appreciated that when the cylinder 40 is lled with treating agents, the hollow cylinder 44 and annular piston 48 will remain in the position illustrated in FIG. 1 until the thin-walled closure member 31 is punctured. Thus, until the shaped charge 32 is detonated, the forces tending to move the hollow cylinder 44 and piston 48 upwardly must equal the forces acting downwardly thereon. Since each of these forces is equal to the product of a pressure multiplied by the effective cross-sectional area that it acts upon, by reference to FIG. 1, the forces can be expressed as:
(Phys) (A3-Ai) -l- (Pwd-Perm) (A2) (As-"AO It will be appreciated that (A3-A1) will be very nearly equal to A2 and that Pam will be practically negligible. Thus, it will be realized that the pressure developed (Pdev) in the treating cylinder 40 Will be very nearly double the hydrostatic pressure (Phyd) of the well control fluids 21. Accordingly, if for example, the ratio of developed and hydrostatic pressure is in the order of 1.811 and the hydrostatic pressure is 10,000 p.s.i.g., it will be appreciated that the injection pressure will be 18,000 p.s.i.g. Thus, if the natural formation pressure is 9,000 p.s.i.g., the treating agents in the cylinder 40 will be injected at an effective differential of 9,000 p.s.i.
Accordingly, the hydrostatic pressure of the well control fluids 21 will act on the injector 43 to exert a multiplied pressure on the treating agents in the chambers 55- 57 to sequentially discharge the treating agents from the chambers through the fluid passage 41 thereabove. This. multiplied pressure produces a high effective differential pressure relative to formation pressures.
A pressure transducer 63 is provided to continuously monitor the pressure in the fluid passage 29. This transducer 63 may, for example, be of the type shown in FIG. 9 of the aforementioned Desbrandes patent, and is connected by an electrical lead (not shown) via the cable 11 to the pressure indicating-and-recording apparatus at the surface of the earth. Thus, by observing the variations in pressure measurements, an operator will be advised of the progress of the operating cycle of the well completion tool 10.
Turning now to FIG. 2, an elevational view, partially in cross-section, is shown of one manner in which the intermediate section 17 may be arranged with the sealing means 18 and 19 and with reference numerals used in conjunction with FIG. 1 to identify the corresponding elements. Shaped charge chambers 25 and 26 are formed in the intermediate section 17 and tilted in such a manner that their central axes intersect a short distance in front of the forward ends of the chambers. The shaped charges 32 and 37 are secured and iiuidly sealed in the chambers 26 and 25 behind threaded tubular members 64 and 65 having enlarged-diameter flanges 66 and 67 on their forward end. The anges 66 and 67 support annular elastomeric sealing members 68 and 69 that are received within forwardly facing counterbores 70 and 71 in the section 17 and iluidly sealed therein by O-rings 72 and 73. O-rings 74 and 75 around the central portion of the closure members 64 and 65 provide Huid-tight annular spaces 76 and 77 in the forward end of the lateral chambers 25 and 26, with radial bores 78 and 79 connecting these spaces to the central bores 80 and 81 through the cl-osure members.
The sealing members 68 and 69 are comprised of con centrically arranged outer and inner elastomeric rings 82-85 mounted on opposite sides of annular reinforcing members 86 and 87. Shoulders 88 and 89 directed inwardly from the `rear of the reinforcing members 86 and 87 are secured against the forward faces of the tubular members 64 and 65 by the forward thin-walled closure members 31 and 36. The forwardfaces 90 and 91 of the sealing means 18 and 19 are skewed in the vertical plane and curved in the horizontal plane to ensure that they will conform to the curvature of a casing or borehole wall. It will be appreciated that the reinforcing rings 86 and 87 will prevent the outer elastomeric rings 82 and 84 from being extruded radially inwardly whenever the hydrostatic pressure of the well control fluids 21 is greater than the pressure within the central openings 27 and 28. Similarly, the inner elastomeric rings S3 and 85 will be supported against radial outward extrusion whenever the pressure within the central openings 27 and 28 is greater than that of the well control fluids 21.
The thin-wal1ed closure members 35 and 36 are spaced i apart and threadedly secured in the central bore 81 through the upper tubular member 65 on opposite sides of the radial bores 79 to block the central opening 27 and isolate the shaped charge 37. The fluid passage 33 connects the bore 81 between the thin-Walled closure members 35 and 36 to an enlarged bore 92 thereabove that is closed at its upper end to provide the atmospheric chamber 34, The detonating means 33 for detonating the shaped charge 37 are comprised of a `short length of detonating cord 93 disposed on the rear of the shaped charge 37 that is coupled to a conventional electrical detonator 94 received within a transverse passage 95 extending upwardly from the shaped charge chamber 25. The other thin-walled closure members 30 and 31 are arranged in the same manner and define a space in the central Ibore S0 of the lower tubular member 64 that is connected by a fluid passage 96 to the main iiuid passage 29 in the lower section 16 (FIG. 1). The shaped charge 32 is similarly detonated in the same manner by the det-onating means 38 comprised of a detonating cord 97 and electrical detonator 98. The hydraulically actuated pistons 22 are mounted in hydraulic cylinders at each end of the section 17, with the back-up shoe 23 being normally retracted against the rear face of the section 17.
Turning now to FIGS. 3-5, the successive steps of the method of the present invention are schematically illustrated as they would be performed by the well completi-on tool 10. Although the exact arrangement will, of course, be determined by the particular consolidating materials to be used by way of example, a pre-flush fluid 99, such as a saline solution, is contained in the upper chamber 55 of the treating agent cylinder 40; the intermediate chamber 56 contains a suitable plastic consolidation agent 100, such as a formaline-cresol mixture, while the lower chamber 57 contains an after-flush agent 1011 such as kerosene. Other consolidating agents and associated reagents that may be used would include those described in U.S Patents Nos. 3,070,161, 3,097,692, and 3,100,527.
VAfter the treating agents 99-101 have been `deposited in the cylinder 40, the tool 10 is assembled and positioned in the well bore 13 adjacent a selected formation 102. By actuating the hydraulic system, the back-up shoe 23 is extended to shift the tool laterally and sealingly engage the sealing means 18 and 19 against the casing 12. Once the sealing means 18 and 19 have been firmly seated, it Will he appreciated that the central openings 27 and 28 in front of the thin-walled closure members 31 and 36 will be isolated from the well control fluids 21 in the well bore 13. At this time, the hydrostatic pressure of the Well control fluids 21 will have -displaced the pre-flush fluid 99 from the upper chamber 55 through the normally-open valve 42 and into the space in bore 80 between the thin-Walled closure members 30 and 31.
As best seen in FIG. 3, the lower shaped charge 32 is then detonated to puncture the thin-walled closure members 30 and 31 and produce a perforation 103 that is directed into the formation 102 in a slightlyupward ydirection. As the perforating jet punctures the closure member 31, the pre-flush fluid 99 (which is at a high ef fective differential pressure relative to the pressure of the formation fluids) will be immediately displaced into the perforation 103. As the pre-flush fluid 99 is exhausted from the upper chamber 55, it will be.` realized that the full pressure developed in the treating cylinder 40 by the injector 43 will be available to inject this agent at a high flow rate into the formation 102. Thus, by injecting the preflush fluid 99 into the formation 102 at this elevated pressure, the agent will be able to break through any residue left in the perforati-on 103 by the shaped charge 32 and enter the formation.
It will'be appreciated that although the fluid pressure Within the central opening 28 is higher than the hydro static pressure of the Well control fluids 21, the forward end of the reinforcing member 86 will be against the casing 12 and sealing member 83 will be sealed therewith. However, the reinforcing member 86 will support the sealing member 83 and prevent its radially outward extrusion.
As best seen in FIG. 4, once the pre-flush fluid 99 has been expelled from the upper chamber 55, the upper floating piston 58 will have reached the top of the cylinder 40 to open the valve 60 therein. Then, the continued application of the developed pressure by the injector `(-13 will displace the remaining treating agents 100 and 101 in controlled sequence-from the intermediate and lower chamber 56 and 57 through the low restrictor 62 and into the formation 102. As these other treating agents 100 and 101 are injected into the formation 102, the consolidating plastic agent 100 will harden and, in time, consolidate the loose formation.
It has been found that 4by injecting the rst treating agent (such as the pre-Hush iiuid 99) at a high flow rate and pressure, loose sand cannot flow back into the tool 10 and the perforation 103 will be prevented from collapsing. It has been found advantageous, however, to inject the other treating agents 100 and 101V more slowly and with only suicient pressure to overcome the formation pressure so that these agents will not channel but will instead permeate and uniformly ll the interstitial voids between the individual sand particles. It will be understood, however, that the yfull developed pressure of the injector 43 is always available and, where a greater press-ure is needed, the iiow rate will merely be reduced by the restrictor 62 as the pressure downstream thereof increases.
Once the treating agents 99-101 have been exhausted, the tool 10 is left in position, as seen in FIG. 4for a period of time calculated to be suiiicient for the plasticconsolidating material to have suiliciently iirmed or congealed t0 form a porous barrier, as at 104, around the perforation 103. This interval of time will, of course, depend upon the setting characteristics of the particular plastic employed. Then, once the plastic agent is calculated to have rmed or hardened, as best seen in FIG.
5, the upper shaped charge 37 is then detonated to produce a second perforation 105 that either intersects the first perforation 103 or comes in close proximity thereto. It will be appreciated that by perforating into the firmed or hardened porous portion 104 of the formation 102, the perforation 105 will not collapse. Moreover, fluid communication will be suddenly established through the second perforation 105 to the atmospheric chamber 34. Thus, by suddenly opening communication from the formation 102 to the atmospheric chamber 34, the formation pressure will displace the connate fluids into the perforation 105 and up into the atmospheric chamber and flush the debris from within the perforation to leave a relatively uncontaminated and stabilized surface. It will be realized, of course, that a conventional normallyclosed valve could also be employed in passage 33.
It should be noted that the sudden drop in pressure within lthe central openings 27 and 28 of sealing means 18 and 19 will cause the outer sealing rings 84 and 82 to lrbe tightly sealed against the casing 12 by the hydrostatic pressure. Tubular reinforcing members 86 and 87 will, however, prevent extrusion of sealing rings 82 and 84 into the central openings 27 and 28.
The consolidation agents used in performing the present invention may be either porous-setting or solid-setting plastics. The invention is not limited, however, to any particular type of sand consolidating agent so long as it is capable of ul-timately providing a porons barrier within the formation around the perforation through which it is ejected. Typical types of sand consolidation agents that may be used generally include (1) a porous-setting type of plastic wherein a phase separation takes place to leave hardened plastic around the sand grains and open pore spaces between the sand grains; (2) a porous-setting type of plastic that shrinks and cracks -upon setting to form openings within the consolidating region to allow passage of connate fluids; (3) a solid-setting type of plastic wherein, after the plastic is injected, after-flush fluids are injected to wash away the plastic from the pore spaces between sand particles to provide sufficient permeability for flow of connate fluids; and (4) a solid-setting type of plastic wherein at least two of its constituents are kept separated from one another within the treating agent cylinder 40 and are successively injected into the formation to mix in situ.
It Will be further realized that the particular nature of the sand consolidating agent employed will govern whether either a pre-flush or an after-flush agent are required. Thus, the treating cylinder 40 needs only to contain whatever agents or constituents thereof and arranged in whatever sequence that are considered to be necessary to obtain a porous consolidated portion as at 104 that is calculated to be sufficiently firmed when the second shaped charge 37 is detonated that the resultant perforations 105 will not collapse. Accordingly, the present inven- -tion should neither be considered as being limited to any particular one or genus if sand consolidating agents nor requiring pre-flush or after-flush fluids unless necessary to achieve the above-mentioned firming reaction.
Once the operation has been completed, the hydraulic system is actuated to relieve the hydraulic pressure therein to retract the back-up shoe 23 and allow the tool 10 to be withdrawn from the well bore 13.
Accordingly, it will be seen that to practice the abovedescribed method of the present invention, the tool is positioned in the borehole 13 adjacent to the formation 102 of interest. The sealing means 18 and 19 are urged against the casing 12 to isolate a surface from the well control fluids 21. Then, the formation 102 is perforated, as at 103, through the isolated surface to permit injection of formation-consolidating agents, ,such as plastic 100, into the formation which, in time, will harden to form a porous support, as at 104, adjacent to the entry hole -through the casing 12. Thereafter, when the porous support 104 has become sufliciently firm, the formation 102 is again perforated, as at 105, through the isolated surface to open communication from the last perforation to a lowpressure chamber, such as at 34, for receiving connate fluids from the pormation 102 to flush the perforation 105.
Thus, it will be appreciated that the present invention has provided new and improved methods for consolidating earth formations and providing fluid passages therein that are free of objectionable low-permeability debris so that connate fluids `may be subsesuently produced therefrom at reasonably high flow rates without also dislodging loose formation particles.
While particular embodiments of the present invention have been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.
What is claimed is:
1. A method of completing a cased Well bore containing a column of well control fluids and traversing an earth formation believed to include unconsolidated particles, comprising the steps of: perforating through a casing and into a formation believed to include unconsolidated particles to provide a first passage therein; injecting a formation-consolidating agent into said first passage for consolidating unconsolidated formation particles within a zone contiguous with said first passage; and, when said formation-consolidating agent is calculated to have firmed, perforating through the casing and into said consolidated .formation zone to provide a second passage calculated to terminate therein.
2. A method of'completing a cased Well bore containing a column of well control fluids and traversing an earth formation believed to include unconsolidated particles, comprising the steps of: packing-off a casing to isolate a portion thereof from the well control fluids; perforating through a casing and into a formation believed to include unconsolidated particles to provide a first passage therein; injecting a formation-consolidating agent into said first passage for consolidating unconsolidated formation particles within a zone contiguous with said first passage; when said formation-consolidating agent is calculated to have firmed, perforating through the casing at said isolated portion and into said consolidated formation zone to provide a second passage calculated to terminate therein; and withdrawing debris from said second passage.
3. A method of completing a cased well bore containing a column of well control fluids and traversing an earth formation believed to include unconsolidated particles comprising the steps of: packing-off first and second portions of a casing from the well control fluids; perforating through the casing at said first isolated portion and into a formation believed to include unconsolidated particles to r provide a first passage therein; injecting a formationconsolidating agent into said first passage for consolidating unconsolidated formation particles within a zone contiguous with said first passage; when said formationconsolidating agent is calculated to have firmed, perforating through the casing at said second isolated portion and into said consolidated formation zone to provide a second passage calculated to terminate therein; and withdrawing debris from said second passage into said receiver.
4. A method of completing a cased well bore containing a column of well control fluids and traversing an earth formation believed to include unconsolidated particles comprising the steps of: packing-off first and second portions of a casing to isolate said first and second portions from the well control fluids; perforating through the casing at said first isolated portion and into a formation believed to include unconsolidated particles to provide a first passage therein; injecting a formation-consolidating agent into said first passage for consolidating unconsolidated formation particles within a zone contiguous with said first passage; when said formation-consolidating agent is calculated to have irmed, perforating through the casing at said second iso-lated portion and into said consolidated formation zone to provide a second passage calculated to terminate therein; and reducing the pressure at said second isolated portion to produce connate fluids from the formation for flushing debris from said second passage.
5. A method of completing a cased well bore contain ing a column of well control fluids and traversing an earth formation believed to include unconsolidated particles, comprising the steps of: packing-ofrp rst and second portions of a casing to isolate said portions from the Well control fluids and from one another and positioning a receiver at a reduced pressure adjacent to one of said isolated portions and a source containing a formationconsolidating agent adjacent to the other of said isolated portions; perforating through the casing at said other isolated portion and into a formation believed to include unconsolidated particles to provide a first passage therein; injecting said formation-consolidating agent from said source and into said first passage for consolidating unconsolidated formation particles Within a zone contiguous with said rst passage; when said formation-consolidating agent is calculated to have tirmed, perforating through the casing at said one isolated portion and into said consolidated formation zone to provide a second passage calculated to terminate therein; and establishing fluid communication between said second passage and receiver for discharging debris from said second passage into said receiver.
References Cited UNITED STATES PATENTS 20 CHARLES E. OCONNELL, Primary Examiner.
DAVID H. BROWN, Examiner.
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