US2860853A - Method of jeep hole completion - Google Patents

Description

Nov. 18, 1958 Filed Feb. 21. 1955 2 Sheets-Sheet 1 ATTOWEY Noir. 18, 1958 H. s. BRIGHAM 2,860,853

METHOD OF JEEP HOLE COMPLETION Filed Feb. 21, 1955 2 Sheets-Sheet 2 29% um I 31 -9 BY 6 (I z I ATTORNEY United States Patent METHOD OF JEEP HOLE COMPLETION Harry S. Brigham, Los Angeles, Calif assignor to Western Gulf Oil Company, Los Angeles, Calif., a corporation of Delaware Application February 21, 1955, Serial No. 489,599 4 Claims. (Cl. 25-13) This invention relates to improvements in a method of jeep hole completion, such a hole being a'partially cased, small diameter hole similar to those drilled for structural observation purposes, but which is completed as a producing well. Substantial savings are realized-in the drilling and completion of such a hole over the expense incurred in usual commercial operations.

An achieved object of the present invention is to provide a method of well completion wherein a smalldiameter hole is only partly cased in depth and is completed as a producing well by setting spaced packers as a part of the production tubing string in the open hole above the production zone to isolate an annular space around the production tubing, and thereafter forcing a fluent packing material into such annular space and retaining it, whereby communication between the production zone and overlying strata is blocked and a large quantity of easing which otherwise would normally be used is eliminated.

Another object of the invention is to provide a method of well completion which is particularly adaptable for employment in areas where formation movements are such as may shear well casing. Thus, it comprises running a production tubing into open hole of such larger diameter that the surrounding annulus may be filled with protective cushioning liquid which alone furnishes lateral support for the tubing through the shear area.

Other objects and advantages will be evident from the following description, with reference to the accompany ing drawings in which,

Fig. 1 is a vertical sectional view of a jeep hole with the assembled tubing in place and with packers set preparatory to circulating a cushioning fluid into the annulus about the well tubing.

Fig. 2 is a similar vertical sectional view showing the tubing with circulation ports open for introduction of cushioning fluid into the annulus.

Fig. 3 is a detail view of that portion of the tubing indicated within the span of bracket A, Fig. l, the tubing being shown in elevation on one side of the center line and in section on the other side thereof.

Fig. 4 is an enlarged detail view, partly in vertical section, of the equipment indicated within the span of bracket B, Fig. l.

Referring more particularly to the drawings, it will be observed that only the upper part of the hole is cased and that the lower, uncased portion 2, 3 of the hole is of stepped diameter, being formed with a shoulder 12 which is located above the oil bearing stratum 13. An

oil-base drilling fluid'is used in drilling the hole and in subsequently reaming it from the shoulder 12 upwardly to the seat of easing 1 and downwardly to total depth.

Pipe 10, which constitutes the uppermost portion of a string of production tubing, is lowered into the hole, such pipe having a separable circulation joint 14 attached thereto by a threaded nipple 15. The circulation joint comprises an inner tubular sleeve 16 which is secured to the nipple 15 by threaded connection and thus is mov- "ice able with the pipe 10. The inner sleeve 16 is formed with'a plurality of ports 11 and carries packing 17 both above and below the ported area to seal against the inner surface of an outer tubular sleeve 9. The inner and outer sleeves are normally telescoped one within the other as shown in Fig. 3 and are latched in this position by means which may be released by turning the pipe 10. This latching means (which is essentially a Baker No- Left Turn Latching Sub, Model B, Product No. 4731 as advertised in the 1954 Edition of Composite Catalog of Oilfield and Pipeline Equipment, pages 502, 503) comprises a plurality of fingers 18 which are capable of being outwardly spread and which are threaded as at 19 to engage with threads on the upper end of sleeve 9 by camming action when the two sleeves are entered into telescoping relation as shown in Figs. 1 and 3. The fingers 18 are guided at their upper ends-in an annular groove 20 between the nipple 15 and inner sleeve 16 and have sufficient lateral play to be urged outwardly at their lower, threaded ends by some such means as a serpentine spring 21. The pipe 10, inner sleeve 16 and spring-pressed fingers 18 thus move as a unit as the sleeves are telescoped to latch them together, and when fingers are backed ofi of the engaging threads on sleeve 9 so that the sleeves may ,be separated a limited distance, as shown in Fig. 2. In this latter position the ports 11 are exposed.

The sleeve 9 is, in turn, connected by a screw threaded nipple 22 to a sleeve 23 which carries packers 8 of rubber or other compressible material, the lower end of sleeve 23 having an outturned flange which engages behind an internal shoulder of the next lower sub-assembly 24, so that the parts may slide one within the other to a limited extent as the packers are compressed. Thus, the end of the sub-assembly 24 bears upon the end of lower packer 8, and the packers may be compressed and deformed outwardly into contact with the wall of the hole by allowing the weight of the tube string to rest upon the packers through sleeves 9 and 23' and nipple 22 and to be, transmitted to the lower sub-assemblies which are supported by seating at the bottom of the hole.

nulus.

The next sub-assembly below the assembly 24 comprises a pipe section 25 in which outwardly opening valves 7 afford communication with the surrounding an- Each valve 7 comprises a flat strip of spring metal anchored at one end to the pipe and having a plug at its free end which covers a port in the pipe. The spring strips urge the valves to closed position. As shown in detail in Fig. 4, the pipe section 25 is provided with a circular series of side ports 26 which are normally closed by heads 27 mounted on the ends of spring metal strips 28, the other ends of such strips being anchored by some such means as a circumferential band 29 which may be welded to the pipe 25.

Below the valve 7, on pipe section 25, the cup packer 6 is mounted by means of a metal thimble 30 which is welded to the pipe 25. The packer is of rubber and its lip is of larger diameter than the hole 3, whereby when it is entered into the hole it will seat securely against the wall and will isolate the production zone therebelow from the annulus above the shoulder 12 as shown in Figs. 1 and 2.

The next lower sub-assembly constitutes a perforated strainer 4 which lies within the production zone of the well.

The tubing comprising the foregoing connected subassemblies is lowered into the hole and the cup packer 6 is set down in the smallest diameter hole 3 immediately below the shoulder 12.

Drilling fluid is displaced and plastic or a resin cement such as Hydromite, a trademarked product of United Pa tented Nov. 18, 1958 1 a,eeo,saa

the tube string.

Pipe 10 and its attached circulation joint are then allowed to subside by weight, 'causingthe wall packers l to be distorted by compression and forced into contact with the wall of the hole. Squeezing of plastic into the annulus between the cup packer 6, and wall packers I is continued until the space is fllled and any excess plastic remaining in the tube string is then drilled out.

Pipe 10 is next rotated to unscrew the threaded connection l! at the circulation joint 14 whereupon the pipe IQ is raised with the inner sleeve and portal! are thereby exposed. Circulation of drilling fluid is established in the direction indicated by arrows in Fig. 2 and is followed by pumping in a cushioning fluid to flll the annulus in the uncased portion of hole 2 above the wall packers 8. One such desirable cushioning fluid is Ken Pak. a product of Ken Corporation. The cushioning fluid ia'thixotropic, setting up to a jelly-like consistency when quiescent. When all drilling fluid has been displaced from the annulus by the cushioning fluid the circulation joint is again closed by lowering pipe 10 whereby sleeve 1 telescopes into the sleeve 9.

The cushioning fluid which fills the annulus supports the well tubing through zones where shear stresses are likely to occur as a result of earthquaim and minimizes the possibility of ensuing damage to the well and equipment. Furthermore, costs are reduced not only because the hole is of smaller size than is usual in a producing well but also because a large amount of casing is saved.

An understanding of the present method may best be gained by reference to an actual operation, although it is to be understood that pipe sizes, depth of hole and other dimensions hereafter stated are given only by way of example and are not intended as the inven tion. With such preliminary explanation, the steps were performed in a typical practice of the invention, as follows, these including certain conventional procedures such as gamma-ray and other surveys which usually accompany well drilling and which are not in themselves claimed herein although referred to for more comprehensive description:

(1) After the well location has been prepared with a cellar, drill hole to a depth of approximately twenty feet and install 10%" conductor pipe therein.

(2) Drill a 9%" hole from the lower end of the conductor pipe to a depth of about four hundred feet. Install and cement 7" O. D. surface pipe in the hole so drilled.

(3) Establish circulation of oil base drilling fluid the hole andwhile circulating the fluid drill 6%" hole 2 to approximately 10' above the top of the production zone.

(4) Drill 4%" hole 3 to total depth. This smallest diameter hole is herein designated a rat hole for purposes of description.

(5) Run gamma ray, induction and caliper surveys from total depth to bottom of 7" surface pipe.

(6) Ream the 6%" hole from the bottom of the 7" surface pipe to the shoulder formed at its junction with the 4%" hole, and ream the 4%" hole from the shoulder to total-depth.

(7) Connect the successive sub-assemblies of the production tubing heretofore described, starting with the perforated strainer section which will be lowermost in the well, and as their connection proceeds lower them into the hole. The cup 'packer 6, cup up, is positioned within the 4%" hole some two or three feet above the top of the production zone when the strainer rests on bottom. At its upper end the string of production tubing is set in slips in a landing assembly of conventional design, not shown. 7

(8) Run in push-out tool (loaded with plastic) on a string of 1%" tubing and if the ports controlled by the 4 spring biased valves 7 break down, pump suflicie'flt plastic to flll the annulus between the lower and upper packers 6 and 8. A suitable tool for this purpose is theMacGafley Taylor C. P. Straddle Tool which is illustrated in the Composite Catalog of Oilfield and Pipeline Equipment, 1948 Edition, page 2552-53. A tool of this type comprises a mandrel having an internal passageway which terminates in a side port, above and below which flexible cup packin'gs are mounted on the mandrel, these packings being so flared as to be spread outwardly into sealing contact with the surrounding tubing by pressure which is applied to the fluid trapped in the intervening annular space with which the side port communicates.

(9) Set the upper, formation packer 8.

(10) Test for water shut-ofl eflectiveness immediately above the producing formation.

(11) Manipulate pipe 10 by rotating it in a direction to disconnect the threaded fingers 18 from the outer tubular sleeve 9 and thereupon drawing pipe 10 upwardly to untclescope the inner sleeve 16 from the outer one to open ports 11 in circulation joint 14, Fig. 2, and establish circulation of drilling fluid in the annulus around the tubing within the 6%" hole 2. Circulation through ports 11 is established by pumping drilling fluid down the tubing string which is temporarily-blocked below the ported area of the inner sleeve 16, such blocking being effected by lowering into the pipe 10 and inner sleeve a circulation mandrel carrying at its end a tubing packer which diverts the flow of fluid out through the ports 11 and upwardly in the surrounding annular space.

'(12) When the circulation is established, pump in sumcient cushioning fluid (preferably one of non-corro sive character) to displace the drilling fluid from the annulus, and close the circulation ports 11. The cushioning fluid is thixotropic, having the property of setting up to a stilt gel upon standing, and thus serving as a supporting cushion between the tubing which is largely exposed to uncased hole, but liquefying when agitated by movement of the tubing, so that the portions of tubing which have suflered corrosion or sucker rod wear may then be readily drawn from the hole for replacement or repair.

- (13) Remove the oil based drilling fluid from the tubing by flushing with clean oil.

(14) Install a pump in the tubing.

The pump may be operated mechanically by sucker rods, or it may be of gas lift type. In the latter case, 1% tubing could be landed after circulating out the oil base fluid and the well thereupon placed on gas-lift by circulating gas through the 1%" tubing, or through the annulus between it and the surrounding tubing.

What I claim as my invention is:

l. The method of completing jeep holes as producing wells comprising drilling hole to within a short distance above the upper horizon of at producing formation, drilling a rat hole therefrom into the producing formation, reaming the rat hole and the larger hole thereabove to form a shoulder at their juncture, assembling tubing to provide a perforated lower portion adapted to extend into the rat hole and mounting spaced packers thereabove, the tubing above the packers having ports which are controlled by relative movement of adjacent sections of the tubing as manipulated from the surface, running the tubing into the hole to total depth, seating the lower of said. packers within the rat hole to seal it from the larger bore above, expanding the upper of said packers to engage the wall of the larger bore and thereby to isolate the annulus between the packers, manipulating the tubing to open the ports therein above the upper packer, establishing a circulation of drilling fluid through the annulus between the larger hole and tubing, displacing the drilling fluid from the annulus by a protective cushioning liquid to support the tubing in spaced relation to the wall of the hole, manipulating the tubing to close short distance above the producing formation, and drilling a rat hole therefrom into the producing formation, running in tubing having circulation ports which are uncovered by manipulation of the tubing from the surface and having spaced packers therebelow and above its perforated lower end, engaging the lowermost of the packers with the wall of the rat hole adjacent to its juncture to the larger bore above, with the tubing resting on bottom, expanding the upper packer into engagement with the wall of the larger bore to isolate the annulus between the packers, running a circulation mandrel into upper packer, establishing a circulation of drilling fluidthrough the aforesaid ports in the tubing and into the j annulus between the larger hole and tubing, displacing the drilling fluid from the annulus by a protective cushioning liquid to support the tubing in spaced relation to the wall of the hole, manipulating the tubing to close the circulation ports, flushing drilling fluid from said tubing, and installing pumping means within the tubing.

the tubing, manipulating the tubing to uncover the circulation ports therein, establishing a circulation of a fluid through the annulus surrounding the tubing above the upper packer and after circulation is established displacing such fluid with a protective cushioning fluid,

thereafter manipulating the tubing to close the circulation ports therein, flushing drilling fluid from the tubing, and installing a pump therein.

3. The method of completing jeep holes as producing wells comprising drilling hole to within a short distance above the upper horizon of a producing formation, drilling a rat hole therefrom into the producing formation, reaming the rat hole and the larger hole thereabove to form a shoulder at their juncture, assembling tubing to provide a perforated lower portion adapted to extend into the rat hole and mounting spaced packers thereabove which are adapted to contact the wall of the hole,

the tubing between such packers having valve means opening under pressure to establish communication with the surrounding annulus and having ports above the packers which are controlled by manipulation of the tubing, running the tubing into the hole to total depth, seating the lower of said packers'within the rat hole to seal it from the larger bore above, expanding the upper packer, forcing plastic into the annulus between packers through the valve means in the tubing, manipnlating the tubing to open the ports therein above the 4. The method of completing jeep holes as producing wells comprising drilling hole to within a short distance above the producing formation and thereafter continuing .hole of smaller diameter into the producing formation to total depth, assembling tubing to provide a lower perforated section above which are spaced packers which are adapted to contact the wall of the hole, the tubing between such packers having valve means opening under outward pressure to establish communication with the surrounding annulus and having circulation ports above the packers which are opened and closed by manipulation of the tubing from the surface, running the tubing into the hole to rest on bottom with its lower perforated section within the producing formation and the lowermost of the spaced packers seated in the hole of smaller diameter, introducing plastic through the valve means into the annulus between the spaced packers and expanding the upper packer into engagement with the wall of the larger hole, manipulating the tubing to expose the circulation ports therein above the upper packer, establishing a circulationof drilling fluid through said circulation ports and surrounding annulus, thereafter displacing such drilling fluid in the annulus by a protective cushioning liquid which serves to support the tubing above the upper packer in spaced relation to the wall of the hole, manipulating the tubing to close the circulation ports and thereby retain the cushioning fluid in the annulus, washing drilling fluid out of the tubing, and installing a pump in the tubing.

References Cited in the file of this patent UNITED STATES PATENTS Robinson et a1 Jan. 16, 1942

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