US3565192A

US3565192A - Earth boring mechanism and coordinated pilot hole drilling and coring mechanisms

Info

Publication number: US3565192A
Application number: US755471A
Authority: US
Inventors: Frank W Mclarty
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-08-27
Filing date: 1968-08-27
Publication date: 1971-02-23
Anticipated expiration: 1988-02-23

Abstract

A cylindrical member is lowerable through a drill pipe and latched thereto. Cutters carried on arms hinged to slots in the cylindrical member move outwardly under pressure of the drill fluid through gaps in the lower end of a shoe at the bottom of the drill pipe to underream under the shoe. The cylindrical member has a pilot bit at its lower end and a core barrel in its bore. Roller or diamond cutters may be used.

Description

United States Patent [1113565192 References Cited UNITED STATES PATENTS 2,277,989 3/1942 Kinnear.......,..............

l75/247X 175/258 l75/330X 175/246 175/330 9/1943 Sewell ,335 5/1945 Walker......

3/1956 Williams.......

[72] Inventor Frank W. McLarty 337 S. Edgeeld Ave., Dallas, Tex. 75208 [2l] Appl. No. 755,471 [22] Filed Aug. 27, 1968 [45] Patented Feb. 23, 1971 [54] EARTH BORING MECHANISM AND COORDINATED PILOT HOLE DRILLING AND CORING MECHANISMS 12 Claims, 55 Drawing Figs.

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Claims

1. An earth-boring mechanism employing in continued workable cooperative conjunction in all kinds of rocks: a rotatable tubular cylindrical drill pipe having threaded means on the lower tip thereof whereby is fixedly attached to said lower tip a tubular cylindrical shoe having through the lower margin thereof multiple gaps, equally spaced from each other around the rotational axis of said shoe and drill pipe with each gap having one vertical side thereof in said shoe margin; means attached to the interior cylindrical wall of said shoe intermediate said gaps therein whereby there is rotationally oscillated within said shoe, around its rotational axis, a generally cylindrical central main body member, having an outside diameter very slightly less than internal diameter of said drill pipe, and having a vertical cylindrical canal through the center thereof having adequate diameter to carry downward under pressure sufficient drilling fluid to carry all rock cuttings upward around said shoe, of a rock drilling mechanism installable through said drill pipe and having means attached to the cylindrical exterior thereof that operate in conjunction with said means attached to the interior cylindrical wall of said shoe, when said body member enters said shoe from said drill pipe, thereby so rotationally disposing said drilling mechanism with respect to the gaps in the lower margin of said shoe, when the means attached to the interior wall of said shoe ultimately limit downward movement of the drilling mechanism in said shoe and thereby prevent passage completely through said shoe, that arms hingeably mounted adjacent their upper tips in vertically disposed slots in the exterior wall of said central body member and having rock disintegrating means attached to the lower tips thereof are free to hinge outward into said respective gaps in the lower margin of said shoe, which thereafter in rotational drilling limits outward hinging of said arms and simultaneously rotates directly, around the rotational axis of the drill pipe, said arms, whose rock disintegrating means attached to the lower tips of said arms respectively serve to underream the drillpipe shoe in the rotational drilling process.

2. An earth-boring mechanism specified in claim 1 in which the cylindrical main central body member thereof, having an external diameter almost as the tubular cylindrical drill pipe through which it is installed in the tubular cylindrical shoe, fixedly attached to the lower tip thereof and having means preventing said central body member from passing on out the lower end of said drill pipe, is provided with means in the upper part of that main central body member whereby hydraulic pressure of drilling fluid, descending through the drill pipe, (at the election of the driller controlling connection of said drill pipe with a pump driven by suitable means adjacent the head of the well, and into a suitable vertical canal passing through the center of the generally cylindrical main body member, actuates the upper tips of multiple suitable dogs pivotally mounted in respective vertical slots in the upper portion of said main body member to force said upper tips of said dogs outward from said main body member and into an annular space below the lower end of the drill pipe having its threaded lower tip screwed into the tubular cylindrical shoe fixedly attached thereto, thereby causing said main body member pivotally mounting said dogs in the slots therein to remain fixed with respect to the shoe and drill pipe in which it thus becomes fixedly mounted until such time as the hydraulic pressure of the pump at the head of the well is cut off by the driller, at which time suitable small springs mounted in the respective slots in the main body member cause said dogs to recede into said slots to such extent that said main body member can be drawn upward through said drill pipe by means of a suitable cable having attached to Its lower tip a grappling mechanism of sufficient weight that the grappling mechanism becomes attached to a lifting device attached to the upper part of the main body member, when the said grappling mechanism and the lower tip of the cable to which it is attached descends sufficiently through the drill pipe from a suitable reel from which it unwinds at the head of the well.

3. An earth-boring mechanism specified in claim 1 in which the central body member of the drilling mechanism has a vertical cylindrical canal through the center thereof, carrying drilling fluid downward and having a diameter at least about one-fifth as great as the diameter of the drill pipe, and has multiple vertically disposed slots, around said vertical canal, in the exterior wall of the generally cylindrical central body member, through which slots, near the upper tips thereof, are mounted corresponding horizontally disposed hinge pins at different elevations in the said generally cylindrical main body member, on which hinge pins are hingeably mounted said arms that hinge outward toward their lower tips into the respective gaps in the lower margin of said drill pipe shoe, below which the rock-disintegrating means in the lower tips of said arms in the rotational drilling process underream a hole of sufficient diameter for the drilling fluid to carry most effectively the rock cuttings upwardly around the drill pipe shoe and the multiple threaded couplings by which the joints of the drill pipe are joined together.

4. An earth-boring mechanism specified in claim 1 in which the generally cylindrical central body member of the drilling mechanism has a central vertical cylindrical canal, carrying drilling fluid downward through the center thereof and having a diameter at least about one-fifth as great as the diameter of the drill pipe, and has in the exterior wall of the generally cylindrical central body member and disposed around said vertical fluid carrying canal of said approximate diameter, multiple vertically disposed slots, in each of which is hingeably mounted on a horizontal pivot pin a vertically disposed arm, which during the drilling process, after the cylindrical main body member becomes fixedly mounted in the drill pipe shoe with respect to which it will not rotate thereafter, is hinged outwardly at its lower tip into one of the duplicate gaps in the drill pipe shoe by means of pressure of the drilling fluid, descending through the central canal of the main body member at the election of the driller controlling a suitable pump at the head of the well, exerted outwardly on the lower half of each said arm by a short cylindrical prod rod mounted loosely in a small canal disposed at an angle with respect to the horizon and connecting the central canal to the vertically disposed exterior slot in the outer wall of the main body member in which said arm is hingeably mounted.

5. An earth-boring mechanism specified in claim 1 in which the generally cylindrical main body member of the drilling mechanism has a vertical cylindrical central canal, carrying drilling fluid downward through the center thereof to the multiple rock-disintegrating means and having a diameter at least about one-fifth as great as the diameter of the drill pipe, and has in the exterior wall of the generally cylindrical central body member, and disposed around said vertical fluid-carrying canal of at least the said dimension, multiple vertically disposed slots, in each of which is hingeably mounted on a horizontal pivot pin a vertically disposed arm, which during the drilling process, after becoming mounted in the drill pipe shoe, is hinged outward at its lower tip, mounting rock disintegrating means, into one of the duplicate gaps through the lower margin of the drill pipe shoe by means of the following mechanism: a pair of duplicating vertically disposed cylindrical holes, spaced apart from each other and from the vertical central canal, drilled upward in the central body member into the corners of the floors of the verTical slots in which the said arms are hingeably mounted; a cylindrical push rod, having a conical upper tip, slidably mounted in each of said holes beneath the diagonally disposed lower face of the lower tip of the arm mounting the rock disintegrating means so disposed that upward pressure on the pair of duplicate pushrods will force the conical upper tips of said rods between the inner face of the vertical slot and the inner face of the arm mounted hingeably therein, which arm thereby has its posture adjusted from vertical and has its lower tip hinged outwardly through the respective gap in the lower margin of the drill pipe shoe; and means reciprocating said multiple arm-adjusting push rods consisting of a tubular cylindrical integrally attached downward extension of the main central body member, of smaller outside diameter than said main central body member, into which all of the multiple said vertical holes, accommodating the respective paired arm adjusting pushrods, extend, but have their lower approximate halves converted into hemicylindrical slots by virtue of the increased diameter of the vertical canal in the lower half of said tubular cylindrical downward extension of said central body member, onto whose externally threaded lower tip is screwed a suitably threaded cup-collar that slidably retains in said enlarged lower half of said downward tubular cylindrical extension of the central main body member a tubular aligning and connecting member having a midsection, of greater outside diameter than the tips thereof, to which the lower tip of each of the multiple vertically disposed adjusting pushrods is attached fixedly, so that reciprocation of said tubular cylindrical connecting member with respect to the main body portion of the drilling mechanism hingeably mounting the several arms therein serves to adjust the angle of disposition of said arms from the vertical positions to which they tend to be held inside their respective slots inside the cylindrical tubular drill pipe by means of small resilient springs mounted around the respective hinge pivot pins on which the respective arms are hingeably mounted; and means of effecting such reciprocation for adjustment of the angles of disposition of said arms from vertical consisting of suitable tool-joint accommodating threads mounted on the conical lower tip of the said tubular cylindrical aligning and connecting member onto which is screwed, below the above-mentioned internally threaded cup-collar, an adapter bushing having corresponding internal tool-joint threads whereby there is attached fixedly to said tubular cylindrical aligning and connecting member a drilling mechanism boring a pilot hole, downwardly ahead of the aforesaid underreaming mechanism, having a diameter almost as large as the internal diameter of the drill pipe through which the generally cylindrical central body member is made to descend, until further downward travel is limited by the shoe mounted on the lower tip thereof.

6. An earth-boring mechanism specified in claim 5 in which the drilling mechanism boring the pilot hole ahead of the underreaming mechanism bores an annular groove around a rock formation core, which thereafter is retained in an inner core barrel provided with a suitable core-catching mechanism, whereby the rock core segment of the formation penetrated is lifted to the well head by means of a cable attached to the upper portion of the main generally cylindrical body member by a grappling member attached to the lower tip of the cable descending through the drill pipe and provided with means whereby said grappling member of sufficient weight to draw the tip of the cable downward and to attach itself to means connected to the said main generally cylindrical body member.

7. An earth-boring mechanism specified in claim 1 and employing the following: a generally cylindrical central main body member which has in its outer wall four vertically disposed slots, in width about one-third of the outside diameter of the drill pipe shoe, in the upper inner tips of which are located vertically disposed ribs, about one-half as wide and one-half as long as said slots respectively, integrally attached to the central section of the body member intermediate said slots, in each of which is hingeably mounted an arm, having industrial diamonds mounted on the lower tip thereof, on a pivot pin having its tips fixedly mounted in said body member, with its horizontally disposed longitudinal axis parallel to the axis of one of the other pivot pins and at right angles to the other two, which have parallel axes disposed at a level almost an inch higher than the axes of the first two pivot pins, and extending through the upper tip of said arm, which tip in horizontal cross section is substantially U-shaped and extends around its respective body rib, which is almost square in cross section at the axis of its hinge pivot extended therethrough, below which the outer face of the respective rib gradually slopes inwardly, at an angle about 30* from vertical, toward the inner wall of the respective slot and disappears as a rib about halfway downward toward the bottom of said slot, which is at the same level as the bottoms of the other three slots; a pair of resilient U-shaped springs mounted around the hinge pivot pin of each of the respective arms tending to keep inclosed in its respective slot each of the said arms, on the lower tip of each of which are suitably mounted industrial diamonds, which tend in combination, by virtue of the fact that the lower tips of all said arms reach downward to the same substantial arcuate level in their respectively accommodating slots, while one diametrically opposed pair of the mounting pivot pins is mounted higher in the body member than the other two diametrically opposed pivot pins at right angles thereto, to underream in the drilling process an enlarged hole of suitable diameter, in excess of the outside diameter of the drill pipe shoe, around a pilot hole, having a diameter almost but not quite as great as the inside diameter of the drill pipe, drilled by suitable means below the generally cylindrical main body member in which the four arms are hingeably mounted; hydraulic means whereby the driller, at his election, can hinge all four of said diamond-mounting arms outwardly, into their respective gaps in the lower margin of the drill pipe shoe by the full arc for each arm permitted by each of the respective duplicate gaps in said shoe, by control of pressure in the drill pipe connected to the vertical cylindrical canal in the center of the generally cylindrical main body member, in which said canal its diameter is reduced slightly in the midsection thereof and below four small cylindrical canals, suitably disposed at angles with respect to the horizon and at right angles to each other in pairs at slightly differing levels, leading from the upper segment of said central canal having the larger diameter to the respective four slots through the central ribs in the upper inner corners of those slots, into which project the outer tips of four cylindrical prod rods of suitable short length that fit loosely in their respective canals, in which pressure from the central vertical canal, at the election of the driller, forces the outer tips of those prod rods against the said diamond-mounting arms intermediate the tips thereof and thereby forces the outer wall of each of the four arms against the roof of its respective gap in the lower margin of the drill pipe shoe; and means keeping the underreaming mechanism, and the larger hole drilled in the rock formations thereby, suitably aligned with the lower smaller pilot hole by employing the following: a tubular cylindrical downward extension of the main body member, said downward extension having an outside diameter only slightly less than the diameter of the cylindrical pilot hole, on whose lower tip are provided suitable threads whereby there is attached to said tubular cylindrical downward extension a guiding tubular cylindrical member, of suitable lengtH and outside diameter to slip easily through said lower pilot hole, whose lower internally threaded tip is closed by a slightly conical member having a vertical hole through the center thereof, in which is fixedly mounted a much smaller vertically disposed pipe having suitable means at the upper tip thereof connecting it to the lower tip of the aforesaid downward tubular extension of the main body member, there being adjacent the upper tip of the guiding tubular cylindrical member multiple orifices through the wall thereof to permit larger rock cuttings to drop into that retaining bucket member from the drilling fluid flowing upward around said tubular cylindrical guiding member.

8. An earth boring mechanism employing in continued workable cooperative conjunction: an internally threaded tubular cylindrical shoe screwed on the lower tip of a rotatable vertically disposed string of tubular cylindrical drill pipe, through which is installed from the head of a well a drilling mechanism whose generally cylindrical main central body member, having an outside diameter almost as great as the internal diameter of the drill pipe through which it is easily slidable, is prevented by said shoe from passing out of the lower tip of said drill string at any time; a tubular cylindrical linkage member fixedly attached by suitable internal threads to the upper threaded tip of said main body member, having a vertical canal through the center thereof with a diameter nearly one-third that of the cylindrical drill pipe, and to the lower tip of a threaded and aligned second tubular retainer member, of smaller diameter than the first and of suitable short length of several inches, whose upper externally-threaded tip is screwed into the lower tip of a lifting and aligning tubular cylindrical member several feet in length having a suitable upper tip, whose outside diameter is almost as great as the internal diameter of the drill pipe through which it is easily slidable, and whose upper face slops downward conically toward the rotational axis of the drill pipe and of the main body member of the drilling assembly installable and removable through said drill pipe; a horizontally disposed circular lifting plate, having a suitable round hole in the center thereof, fixedly attached to said lifting and aligning tubular cylindrical member, immediately above the upper end of the short tubular retainer member, whose upper tip is screwed into the lower tip of said lifting and aligning tubular member, provided with a suitable spider framework attached fixedly to the cylindrical wall of said retainer member and mounting fixedly in the center thereof a small vertically disposed tubular cylindrical seating member, through whose internal threads is screwed a threaded cylindrical adjusting rod having an upper tip with a conical upper face, whose level of disposition in said retainer member is secured by a pair of nuts screwed on the threaded cylindrical adjusting rod immediately above and below the tubular seating member; and a suitable grappling means attached to the lower tip of a cable inserted through the drill pipe when desired and employing the following: four vertically disposed lifting members of sufficient length to provide sufficient weight to pull downward rapidly through said drill pipe filled with drilling fluid the lower tip of the retrieving cable, around which all the four said substantially straight lifting members are fixedly attached thereto by means separating said lifting members from each other and disposing them with their lower tips tending to remain separated from each other by at least the same distances as at the lower tip of the lifting cable, there being attached to the lower tip of each such substantially straight lifting members, having lower ends that slope upwardly toward the axis of the vertically disposed cable, multiple angular latching devices whose upper faces slope upwardly toward their outer tips, which during downward travel of the cable tip are drawn together by a strong cord wrapped and tied tightly around the four vertically disposed lifting members immediately above said latching devices, whose combined horizontal extent is thus minimized to such degree that said latching devices pass readily downward through the suitably shaped round hole in the center of said horizontal lifting plate, whose lower face slopes upwardly from said center hole so that the latching devices will not return upward through said center hole in said lifting plate, in response to subsequent lifting of the cable, after the aforesaid strong cord is broken by downward falling of the four said lifting members against the aforementioned conical upper face of the spearlike cylindrical adjusting rod, mounted fixedly in the center of the tubular cylindrical retainer member a suitable distance below said horizontal lifting plate, which spreads apart the lower tips of the four substantially straight lifting members to which respectively the latching devices are rigidly attached, thereby affording a suitable linkage between the lower tip of said cable and the generally cylindrical main body member of the drilling device.

9. An earth-boring mechanism employing in continued workable cooperative conjunction: an internally threaded tubular cylindrical shoe screwed onto the lower tip of a rotatable vertically disposed string of tubular cylindrical drill pipe, through which is installed from the head of the well a drilling mechanism whose generally cylindrical central main body member, having an outside diameter almost as great as the internal diameter of the drill pipe through which it is easily slidable, is prevented by said shoe from passing out of the lower tip of said drill pipe string; a tubular cylindrical aligning retainer member at least nearly one foot long and having the same outside diameter as the generally cylindrical main body member, to which it is fixedly attached by threads in the lower tip thereof screwed onto the external threads of an upper reduced diameter segment of said main central body member, above the upper end of which by a fraction of an inch are the lower faces of at least two diametrically disposed generally rectangular openings openings, about 1 inch wide and nearly 2 inches high, through the wall of said aligning retainer member, through which openings in said wall respectively are extendable the upper tips of suitable diametrically opposed scotching dogs, whose upper tips during the drilling process are projected into the annular space inside the drill pipe shoe immediately below the lower end of the drill pipe, and whose lower cylindrical tips are mounted in cylindrical cups in the upper face of the main central body member, to which each of said scotching dogs is pivotally attached at its lower tip by means of an arcuate plate having a notch in one side for accommodation of the pivotally mounted oscillatable scotching dog, whose hinge pivot pin is held to the upper horizontal face of the main central body member by bolts extending through holes in said arcuate plate, so that it is possible to pivotally attach the respective dogs to the central body member of the drill mechanism, after there has been mounted on said central body member the tubular cylindrical retainer member and suitable means of adjusting tilt of the said scotching dogs in unison; means of retracting the upper tips of the scotching dogs in unison from their positions in the annular space in the drill pipe shoe, beneath the lower end of the drill pipe, consisting of a tubular cylindrical adjusting member vertically slidable in an annular cavity in the upper tip of the main central body member and within the tubular cylindrical retainer guiding member, said adjusting member having suitable rectangular notches in its upper margin to accommodate the respective scotching dogs, each of which rests substantially on the lower face of its respective notch in said cylindrical adjusting member, when the upper tip of the scotching dog is extended outwardly througH the hole in the wall of the tubular cylindrical retainer member, which has attached to its inner upper margin multiple vertical adjusting rods, intermediate the respective notches in said tubular cylindrical adjusting member, whereby the tubular cylindrical adjusting member is fixedly attached by the upper tips of said vertical adjusting rods of suitable equal short length to a horizontally disposed circular lifting plate, slidably mounted inside the said tubular cylindrical guiding retainer member, provided with a suitable hole in the center thereof, whereby a suitable grappling mechanism fixedly attached to the lower tip of a cable extending downward, when desired, from a suitable reel at the head of the well is employed to raise the horizontal lifting plate, the multiple vertically disposed adjusting rods fixedly attached thereto, and the tubular cylindrical adjusting member fixedly attached to the lower tips of said adjusting rods, thereby slightly raising in unison all the outer tips of said pivotally mounted scotching dogs and thus retracting them inwardly, from the annular space in the shoe beneath the lower end of the drill pipe, toward the rotational axis of the drill pipe, so that the upper tips of said hingeably mounted scotching dogs become retracted into their respective holes through the wall of the tubular cylindrical guiding retainer member, which in turn lifts the main central body member rigidly attached to its lower tip, when the horizontal lifting plate rises a fraction of an inch and thereby comes in contact with the movement limiting lower face of an annular cylindrical member, having an outside diameter the same as the outside diameter of the guiding retainer member, easily slidable in the drill pipe, having external threads, formed on a lower segment of reduced diameter, screwed into the upper guiding retainer member, whereby directly the entire drilling mechanism is lifted through the drill pipe, when the suitable grappling mechanism on the end of said cable descends through the downward sloping conical upper face of said annular cylindrical member provided with a cylindrical hole at the center thereof very slightly larger in diameter than the hole in the center of the horizontal lifting plate; a diffusing spear member having a conical upper face fixedly disposed in the center of said tubular cylindrical guiding retainer member, a suitable distance below the hole in the center of the horizontally disposed circular plate attached to the upper tips of the four adjusting rods, whereby multiple latching members attached to the lower tips of vertical members of the grappling device attached to the lower tip of a cable extending downward, at the election of the driller, through the drill pipe are brought into contact with the lower face of the horizontal lifting plate around the hole through the center thereof, when the cable is raised upward to effect such lifting of the drilling mechanism through the drill pipe for any reason; and means tending to keep the upper tips of the hingeably mounted scotching dogs caught beneath the lower end of the drill pipe in the drill pipe shoe, until such time as the cable lifts the tubular cylindrical adjusting member through whose notches those scotching dogs are disposed, said means of keeping the upper tips of the scotching dogs outwardly extended employing the following: a short tubular cylindrical sleeve, fixedly attached to the wall of the tubular cylindrical guiding retainer member in the midsection thereof, beneath which is mounted the upper tip of a resilient coiled compression spring, whose lower tip rests on the upper end of a short tubular cylindrical sleeve, having an outside diameter slightly less than the tubular cylindrical guiding retainer member, in which it is easily slidable, whose lower end, suitably rounded in cross section for easy accommodation of the several scotching dogs, rests on the diagonally disposed upper faces of the multiple hingeably mounted scotching dogs, whose upper tips thus tend to be Forced outward as far as possible by the downward force of the resiliently flexible coiled compression spring acting on all said scotching dogs in unison.

10. A rotary coring mechanism employing in continued workable cooperative conjunction the following: a tubular cylindrical outer core barrel serving as a rotatable drill pipe whose lower tip core barrel fixedly attached by suitable threads to the upper tip of an annular drill head member, having an outside diameter the same as said rotatable drill pipe, whose upper conical face slopes downward to a cylindrical hole, in the center thereof and about an inch deep, internally threaded for receiving a second rotatable core barrel, whose inner diameter is the same as that of the smaller cylindrical hole extending almost all the way through said annular drill head member with that diameter and thereafter all the way through with a slightly smaller diameter, there being a narrow circular horizontal shoulder adjacent the lower tip of said annular drill bit member, somewhat longer than its horizontal outside diameter, on which shoulder rests a nonrotating core-catching device, of the same internal diameter as the lower smallest cylindrical hole through the lower tip of said annular drill head member, on which in turn rests a notched nonrotating inner core barrel having the same internal diameter as the nonrotating core-catching member and the hole through the lower tip of the aforesaid annular drill head member, which has an outside diameter more than halfway upward from its lower end that is only slightly more than three-fifths of the diameter of the tubular cylindrical drill pipe attached to its upper threaded tip; a diagonally disposed face, conveniently 30* from vertical, cut across said annular drill head member and extending upward diagonally outward from the lower end of the smallest hole through the center of said annular drill head member, into which a hole of suitable diameter is drilled perpendicularly, at a suitable distance upward from said lower tip, and internally threaded for receiving a tip-threaded stud bolt secured in said annular drill head member and serving to mount therearound the inner race of a suitable antifriction bearing, whose outer race is mounted in a suitable rolling cutter, made of suitable hardened steel alloy, whose rolling lower teeth disintegrate the surface of the rock formation immediately around a cylindrical core of small enough diameter to slidably enter the smallest diameter cylindrical hole in the lower tip of said annular drill head member; a second annular drilling head member having an outside diameter at its upper end equal to the outside diameter of the outer core barrel drill pipe and to the maximum diameter of the upper section of the first said annular drill head member, around the lower generally cylindrical section of which is fixedly mounted the second said annular drill head section, which has a generally conical upper face, corresponding to a conical lower face of the upper section, sloping downward toward the rotational axis of the two sections as an auxiliary means keeping the two sections aligned under vertical pressure, and which has multiple keys imbedded in said conical surface serving as very strong means, in addition to multiple bolts inserted perpendicular to the contact surfaces of the two annular drill head members, keeping the upper section from rotating with respect to the lower section, whose lower approximate three-fifths has integrally formed on its outer cylindrical surface four vertically disposed outward extensions by a small fraction of an inch, respectively having arcuate outer faces disposed at 90* intervals around the said second annular drill head member; a suitable recession formed in the lower tip of said second lower outer drill head section to accommodate loosely the aforesaid rolling cutter mounted on an axle pin fixedly attached by suitable means to the lower tip of the smaller diameter lower section of the upper annular drill heAd member; a second axle pin having its longitudinal axis substantially in the same vertical plane containing the first said rolling-cutter axle pin fixedly attached to the lower tip of the upper said annular drill head member, but with the second said axle pin, suitably mounting rotationally a second suitable rolling cutter, being mounted in the lower tip of the lower and outer second said annular drill head member almost member, almost through which, at the midpoint plane of one of the outward arcuate extensions thereof, the threaded hole mounting the threaded tip of said second axle pin extends, the axis of said second rolling-cutter axle pin, mounting a suitable antifriction bearing thereon, being disposed at a smaller angle than the first said rolling-cutter axle pin with respect to the horizon, and the rolling cutter, provided with suitable teeth on a slightly conical face of smaller maximum diameter than the diameter of the first said rolling cutter having a substantially cylindrical outer face for the teeth thereof, describing an annular almost horizontal cutting path on the bottom of the hole larger than the annular rotational path of the first said cutter by virtue of the suitable cylindrical cavity milled in the lower outer second said annular drill head member for rotational accommodation of the second said rolling cutter, for the rotational accommodation of which a suitable cavity also is cut in the adjacent outer wall of the telescoped lower segment of the inner upper first said annular drill head member; a pair of diametrically disposed axle pins, mounted in a vertical plane passing through the rotational axis of the two telescoping annular drill head members perpendicular to the vertical plane including the axes of the two previously mentioned rolling-cutter axle pins, mounted at suitable equal angles with respect to the horizon in suitable cylindrical cavities milled in the lower inner tip of the outer lower said annular drill head member, there being corresponding cavities milled in the outer wall of the inner said telescoped second said annular drill head member rotationally accommodating the upper faces of the two rolling cutters mounted on said pair of axle pins provided with suitable antifriction bearings for said substantially duplicate rolling cutters having suitable teeth in conical faces, which describe an annular path disintegrating the rock formation and thereby cutting a hole of slightly greater diameter than the diameter of the lower outer annular drill head member through the respective outward vertical extensions thereof, between which the rock cuttings are carried upward by the circulating drill fluid, for the downward passage of which through the pair of annular drill head members multiple suitable small holes are provided therethrough at least almost vertically.

11. A pilot hole drilling and coring mechanism consisting of a novel modified annular female ''''box'''' segment of a tool-joint screwed onto the lower ''''pin'''' segment of a conventional ''''internal upset'''' flashwelded joint of drill pipe with said annular ''''box'''' being modified to achieve the following construction: (1) to a distance of 1 inches below the lower end of the above-mentioned ''''pin'''' segment of said conventional joint of drill pipe above it, said ''''box'''' is bored out internally to form a cylindrical canal of suitable diameter, below which said vertical canal becomes conical, at an angle of 30* from vertical, until it reaches the original conventional cylindrical canal through said ''''box'''' segment of the tool-joint; (2) at a level one-quarter inch below said conical section of the canal, an annular shoulder is created by boring that conventional cylindrical canal out downwardly to an internal diameter one-eighth inch greater than above said shoulder, thereby forming a cylindrical cavity in which in due time is installed from beneath and fixedly therein a generally cylindrical insert about 1 1/4 inches high having 12 vertical grooves about three-sixteenth inch deep cut vertically out of the internal surface, remaining after the upper inner tip of said insert is bored out conically to continue the conical downward slope of the canal above said insert in said annular ''''box,'''' of said insert, on which internal arcuate surface between said vertical grooves are mounted multiple industrial diamonds, by a sintering process well-known to the art, for reaming around a rock core remaining after the annular groove in the rock formation has been cut around said cylindrical core by rotation of said ''''box''''; (3) 12 vertical grooves provided in the inner wall of said ''''box'''' and extending outwardly with their respective outer walls being downward extensions of the outer wall of the vertical canal having maximum diameter in said annular ''''box'''' member, each of said 12 grooves being disposed radially in said box with respect to the corresponding 12 grooves in the inner cylindrical wall of the generally cylindrical insert, which is provided with very slight ribs inserted in the respective said grooves in the surrounding ''''box'''' member to keep said ''''box'''' from rotating with respect to the generally cylindrical insert, which also forms a small vertical canal, through which drilling fluid is transmitted downward under pressure from the canal in the drill pipe, in conjunction with each of the grooves in said annular ''''box'''' member, in which those vertical canals extend downward to the lower annular tip thereof, which is formed with a hemispherical vertical cross section; (4) 12 grooves formed in said annular lower tip of said annular ''''box'''' member fixedly accommodating 12 J-shaped steel segments fixedly attached thereto by multiple bolts and other means permitting easy removal therefrom to conveniently replace any of the multiple industrial diamonds installed on the drilling face of each of said 12 J-shaped steel mounting segments individually without having to install diamonds in all of the drill bit.

12. A pilot hole drilling and coring mechanism specified in claim 11 in which is installed from above through said conventional internal-upset flashwelded joint of drill pipe an inner nonrotating tubular cylindrical core barrel having fixedly, but removably, attached to the lower tip thereof a tubular cylindrical core-catching device, having an outside diameter easily slidable through said conventional joint of drill pipe and having a lower tip that fits the upper inner face of the generally cylindrical insert around the rock core, which travels upward relatively with respect to said nonrotating core barrel and into its telescoped smaller vertically slit inner segment, in which said core is retained by a lower suitable collet provided with a suitable conical seat in said tubular cylindrical member fixedly attached to the lower tip of the outer said nonrotating core barrel.