US2586939A - Directed well drilling - Google Patents

Description

Feb. 26, 1952 D. B. GRABLE 2,586,939

DIRECTED WELL DRILLING Filed Nov. 12, 194e 2 SHEETS- SHEET 1 vow/ypzr Y INVENToR.

ArroiP/yfz Feb. 26,1952 D. B. GRABLE DIRECTED WELL. DRILLING 2 SHEETS-SHEET 2 Filed Nov. l2, 1946 JNVENToR.

Arf-WE1 m m M M y 0 M a www n( @as Patented Feb. 26, 1952 UNITED STATES PATENT OFFICE DIRECTED WELL DRILLING Donovan B. Grable, Long Beach, Calif. Application November 12, 1946, Serial No. 709,229 7 claims. (c1. c55-1.6)

This invention has to do with directional well drilling, and contemplates within its general scope improved methods and equipment for conducting defiected drilling operations in a manner productive of numerous advantages distinguishing the invention from the past and conventional practices.

The customary procedures and tools used for directional or deflected drilling employ the usual whipstocks, i. e. deflective barriers set in the Well and generally characterized by their open or exposed angular top surfaces which, when engaged by the drill bits, deflect the latter in accordance with the whipstock orientation. Assuming this orientation to be correct, the accuracy of the bit or bore hole deflection is largely dependent upon the ability of the angular face of the whipstock to direct and maintain the bit in a. certain or predetermined course.

'Experience has shown that a given shape, extentor angularity of an open whipstock deflecting face willv not always assure corresponding deflection of the drill bit (or other formation cutting tool), because of the tendency of the bit to follow courses of least resistance in the formation, which may vary from the course directed by the whipstock. For example, while guided at one side by the whipstock, the bit may encounter relatively softer formations in one or more different directions, and will tend to penetrate and deflect vlaterally of the whipstock, or follow a course above that which the whipstock is intended to establish.

One of my major objects is to provide not only for d-eflecting a bit or cutting tool in a predeterminable course, but also for so confining the tool or immediate portion of the drill string that the tool is guided and confined in all directions laterally of its intended course of advancement and therefore given positive control With respect tof the course which it m-ust follow. Thus, with the guide orientation established, the bit cannot escape its intended cours-e, as for any of the reasons ordinarily responsible for error in the deflection, and the hole can be directed at any angle of defiection with complete accuracy.

More specifically, the invention contemplates providing at the proper location in the well bore, an inclined passagewithin which the tool or bottom portion of the drill string is received and laterally confined in all directions so that upon advancement in a deiiected course determined by the orientation .and angularity of the passage, the tool will be positively fed and rigidly guided. Typically the angular guide passage may be 2 l formed by a drillable tube contained or embedded in a cementitious body of drillable material.

A 'further object of the invention is to so com bine or associate the above mentioned guide passage with the drill string that setting and orientation oi the passage-containing body, and de` lected drilling may occur sequentially in a single operation, thus avoiding the expenditure of time, use of various tools, and multiple trips into and out of the well, customarily required for a Whipstocking operation. In this respect the inven-l tion contemplates lowering the guide passage body together with the bit (While permitting downward uid circulation), and after setting and orienting the body, commencing defiect'ed drilling, all inA a single course of operation.

Particularly the invention aims to employ a novel association of the guide body with spaced pilot and main drill bits so that the pilot 'bit first is deflected to drill a bore to be followed by the main drill bit, and the latter then or simultaneously advances to drill away the guide body and enter the pilot bore.

All the objects and advantages of the invention, as Well as the details of certain illustrative embodiments, will be fully understood from the following' description of the accompanying drawings, in which:

Fig. l is a view taken in vertical section to show the guide body lowered in the well on the pipe string to setting position;

Fig. 2 is a similar view showing the progression of the pilot bit through the guide into the formation;

Fig. 3 shows a further stage in the drilling progression after the main bit has cut through the guide body;

Fig. 4 is a view similar to Fig. 1 illustrating a variational aspect of the invention; and

Fig. 5 is a fragmentary enlarged view illustrating a variational form of releasable connection between the guide body and the pipe string.

Referring first to Fig. l, the guide generally indicated at l0 is shown to be lowered and set in position at the bottom of the bore hole Il which may lbe cased or uncased. The drill pipe string 'l2 is shown to carry an upper or mainl drill bit throughcasing, milling'cutters or drills may be used, or the bits may be made to penetrate casing.

Typically the guide I is shown to comprise a body I6 of cementitious or other non-magnetic drillable material having at its lower end an anchor plate or shoe I1 adapted to penetrate the sand or formation at the bottom of the hole, thuspreventing turning of the body from oriented position. The body contains a tube I8 of nonmagnetic drillable metal characterized by its deviation from the vertical, and specifically formed to have a straight upper portion I8a and a lower extent Ib extending angularly at an inclination desired for the intended deflection of the bit.

This angle of deflection may vary to serve the trative, the pipe I is shown to be' receivedwithin the body a' distance permitting reception ofthe pilot bit I4 in the' tube i8, and to be releasably heldI against downward movement relative' to" the body by means of shear pins I9 carried by the body and received within openings 28 in the pipe fw i5. Suitable packing 2I`may engage about the pipe to confine the circulating fluid against leakage through the top of the body.

As illustrative of `a variational' form of releasable connection between the ldrill string and guide A:

tube body,Y Fig. 5 shows a threaded joint 22 typically in the form of an insert 23 having right hand thread engagement with thethreaded porttion 24 of the tube' section I5. After'the guide tube body is set in orientedpo'sition, the1joint at 22 may be broken by right-hand rotation of-ithe drill string, permitting downward rmovement-of the bits relative to the guide.

In considering atypical offsets'drillingi-opera'- tion, 'assume the 'guide'body assembly 'to be lowered to the bottom ofthe well on' the pipestring inthe described associationandrelation tothe bits I3 and I4 shown in Fig. l. Itv'will be-ob- Aserved that the drill string and guide tube are in Aopen condition permitting maintenancevofdownward fluid circulation during the loweringfopveration, a feature of advantagein permittingtthe guide tube body to be circulated into setting position. Ordinarily it is desired to set thepl-ugata predetermined orientation, i. e. :a position at which the inclined portion I8b of the5 guide tube has a determinable oriented direction. rFor this purpose I may lower on line 25 through the pipe string and into a non-magnetic tube I8 an appropriate orienting instrument, conventionally indicated at 2'6 by which readings may be taken to establish the tube orientation.

With the drillable body and guide tube set in oriented position, the drill string may be'lowered to release the described shear pin or threaded connections, and advance the pilot bit I4 through the .guide tube, causing the bit to assume a correspondingly deflected course as illustrated in Fig. 2. The distance between the bits I3 and I4 may be such that the pilot bit is permitted to drill the formation a more or less extended distance before bit I3 reaches the body I6, thus preestablishing the direction and .inclination of the diverted drill hole before bit I3 commencesto cut away the body and tube assembly I0'.V Upon con- 4 tinued drilling, the pilot bit advances the bore 21 as bit I3 progressively cuts away the drillable material IB and guide tube, circulation at the time being continuously maintained through the drill string to wash away the cuttings. Eventually bit I3 will have drilled through the guide tube body and may be permitted to penetrate the formation in a course following the direction of bore 21, whatever .depthdesired As illustrated inV Fig. 3, bit I3 may be permitted to drill the diverted bore 28 a distance sufficient to preestablish the direction of drilling according to the course of the bore, whereupon the pipe string may be pulled to remove the pilot bit and tube I5. Thereafter drilling may be continued using the i single bit I3 which will follow the course of bore 28' andthe pilot bore 21.

Fig. 4 illustrates a variational procedure employing essentially the same equipment as previously described, but differing in that the pilot bit is inserted within the angular guide tube 'before the assembly is lowered in the well. Here the drillable body 29'i's shown to contain the angular guide tube 3G and packing 3l as before. The drill string 32' includes the upperbit. 33. a non-magnetic tube'section or pilot bit string 34, and the pilot bit S5, the latter in thisinstance Vbeing shown as a closed endV bit, though having circulation openings 35, as distinguished'from the core-type bit I4. Before lowering the assembly into the well, tube 34r and the pilot bit 35 may be thrust down into the guide'tube 30 to the'position illustrated and inzwhich the pilot bit and lower portion of .the tube 34 areA predeilected within the guide. If desirable, areleasable connection may 'be'V effected .'betweeni the guide body and pipe string, as bymeans of a shear pin 31 'interconnecting thepilot bit :and guide tube orbody. As before, circulationmay be maintained through theipipestring in the -operation ofA setting the guide body. .The latter may be oriented by 'lowering on line 33Y the instrument 39 to a position within the non-magnetic pilot bit Ystern and l'ower'angulanportion 30a of the guide tube. With the latter oriented, drilling maybe commenced to progress inthe manner previously described with the condition of the string-and guide assuming the relationships illustrated in Figs. 2' and 3.

I claim:

1. In combination witha pipe Astring'carryng an upper larger diameter-cutting tool and a lower pilot cutting tool, a body releasably connected `to said (pilot cutting tool and adapted tobe'lowered therewith to setting position i'nthe well.

.said body containing a passage which in Yturn contains vsaid'pilot tool and is inclined fromi the vertical "and of sufficientisize to pass said pilot cutting tool within thexbody and cause.- the 'tool to be deflected laterally intoA the formation, and a tubular connection between said pilot tool and said upper cutting tool and'positioning the tools So that following deiiection of the pilot tool into the formation the upper tool engages and drills awaythe body as drilling progresses.

2. In combination with a pipe string carrying an upper largerv diameter cutting tool, and a lower pilot cutting. tool, abody releasably-ccn- `nected Ato said pilot cutting tool'andadapted to be lowered therewith to setting position in the weil, Vsaid body containing a passage which in turn contains said pilot tool and has downward and outward curvature froml the vertical to pass and deiiect said pilot cutting tool laterally into thev formation, and a tubular connection between said pilot tool and said upper cutting tool, said upper tool being positioned in the pipe string directly above the pilottool and being operable to cut awaythe material of said body after deection of said pilot tool into the formation.

3. In combination with a pipe string carrying an upper larger diameter cutting tool and a lower pilot cutting tool, a body of drillable material releasably connected to said pilot tool to be lowered therewith to setting position in the well, a drillable tube in said body and inclined from the vertical, said pilot tool being retained within said tube and movable therethrough to be deected laterally into the formation, and a tubular connection between said pilot tool and said upper cutting tool and positioning the tools so that following deection of the pilot tool into the formation the upper tool engages and drills away the body as drilling progresses.

4. In combination with a pipe string carrying an upper larger diameter cutting tool and a lower pilot cutting tool, a body of drillable material connected to said pilot tool to be lowered therewith to setting position in the well, a drillable tube in said body and inclined from the vertical, said pilot tool being retained within said tube, means releasably connecting said body and pilot tool against relative downward movement of the pilot tool, and a tube section conneiting said cutting tools, said pilot tool being movable upon releasing said connection downwardly through said drillable tube to be deiiected thereby laterally into the formation and the upper tool being positioned in the string to then engage and drill away the body.

5. In combination with a pipe string carrying an upper larger diameter cutting tool and a lower pilot cutting tool, a body of drillable material releasably connected to said pilot tool to be lowered therewith to setting position in the well, a drillable tube extending longitudinally inside said body from the top to the bottom thereof and inclined from the vertical, a pipe section interconnecting said cutting tools, downward uid circulation being maintainable from the pipe string through said cutting tools. and inclined tube, said pilot tool being received within and movable through said tube to be deflected thereby laterally into the formation and the upper tool being positioned `in the string to then engage and drill away the body.

6. In combination with an oil well pipe string carrying an upper -larger diameter ybit and a spaced lower pilot bit, tubing interconnecting said bits, a body lowered to setting position in the well on said tubing and containing a longitudinal passage inclined from the vertical and containing said pilot bit, said passage being open to permit uid circulation downwardly through the pipe string, tubing and body, and means releasably connecting the tubing and pilot bit with the body, said bits being operable to sequentially pass the location of the body first by movement of the pilot bit through said passage and then drilling of the body by said upper bit as the pipe string is lowered and the pilot bit is deected by said passage laterally into the formation. 7. In combination with an oil well pipe string carrying an upper larger diameter bit and a spaced lower pilot bit, tubing interconnecting said bits, a body of cementitious drillable material lowered to setting position in the well on said tubing and containing a longitudinal passage inclined from the vertical and receiving said pilot bit, said passage being open to permit iluid circulation downwardly through the pipe string, tubing, and body, and means releasably connecting said tubing and pilot bit with the body, said bits being spaced so that upon lowering of the pipe string the pilot bit is deected by said passage laterally into the formation and the upper bit is then operable to drill away the material of said body while following a course established by the pilot bit deflection.

DONOVAN B. GRABLE.

REFERENCES CITED The following references are of record in the lile of this patent:

UNITED STATES PATENTS Number Name Date 1,424,109 McBride July 25, 1922 2,043,381 Lane June 9, 1936 2,058,327 Lane Oct. 20, 1936 2,081,294 Eastham May 25, 1937 2,119,746 Lane June 7, 1938 2,227,233 Scott et al Dec. 31, 1940 2,281,414 Clark Apr. 28, 1942 2,334,747 Brantly Nov. 23, 1943 2,498,159 Gammill Feb. 21, 1950 2,498,192 Wright Feb. 21, 1950

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