GB2232178A

GB2232178A - Method for completion of a subterranean well

Info

Publication number: GB2232178A
Application number: GB9012189A
Authority: GB
Inventors: Albert A Mullins
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 1989-06-02
Filing date: 1990-06-01
Publication date: 1990-12-05
Also published as: CA2018054A1; DE4017775A1; GB9012189D0

Description

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APPARATUS FOR COMPLETION OF A SUBTERRANEAN WELL BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION: The invention relates to a method and apparatus for completion of a subterranean well.

2. DESCRIPTION OF THE PRIOR ART: After the drilling of a subterranean oil or gas well, a string of sections of casing are introduced into the well to more properly define the well bore and prevent collapsing or caving in of the well bore walls, and to control the fluids within the well through the various drilled formations. Thereafter, the casing string is cemented in place, in conventional manner. Finally, the casing must be perforated adjacent the production zone to permit communication of the producing fluids into the interior of the casing for subsequent transmission to the top of the well, generally through production tubing concentrically positioned within the casing. As used herein, the phrase "casing string" also includes casing liner strings.

In some situations, prior to production of the well fluids to the top of the well but after perforation of the casing a treatment fluid such as fracturing fluid or other stimulation technique is applied to the formation and is pumped down the well and injected through the casing to the production zone.

2 It frequently occurs that the perforated production zone is not to be produced immediately upon perforation and must be isolated until such time as production is desired.

In the past, isolation of perforated production zones has been achieved by, for example, killing the well with a kill fluid. The use of such kill fluid has been discouraged by some opponents of this technique because of the adverse effect of the interface of such fluid upon the skin of the production zone, resulting in possible contamination and even clogging of the production fissures and pores. Other means of isolating the perforated production zone for subsequent production have included the running and setting of a isolation production packer immediately above such zone and introducing through the bore of the packer a plug member, with the plug member being removable by means of wireline, coiled tubing or other auxiliary device for subsequent production. This means of isolating the perforated prodcution zone is typical, but prevents the running into the well through such packer of logging devices and other remedial equipment for use in activities pertaining to production zones which may be subsequently drilled or completed below the particular zone which has been perforated and which is desired to be isolated for production at a later time.

While valves for opening and closing ports on 1 1 3 production tubing, workstrings, and the like are well known to those skilled in the completion art, valve means carried on casing conduit members forming an integral part of the initial casing string have not heretofore been provided, as a means for closing off perforations through production zones and for controlling the well by isolating such production zones immediately at the perforations.

The present invention is directed to isolating a perforated casing section through a production zone by providing a method and apparatus which controls fluid flow therethrough immediately at and through the casing section, thus eliminating the need for introduction into the well of kill fluids, and eliminating the requirement of introduction into the well of plug means through the central bore of a production packer positioned above the production zone, while, at the same time, permitting tubing or other conduits to be introduced through the well to perform activities at depths below the particular production zone to be isolated.

The present invention also provides a valving arrangement that permits cement placement outside of the casing prior to perforating, thus preventing any cement damage to the valve function.

SUMMARY OF THE INVENTION

This invention provides an apparatus and method for completion of a subterranean well. The apparatus 1 1 4 comprises a casing conduit section member insertable within said well and having means thereon at at least one end thereof for securement, to a casing conduit string. A valve member is carried by the conduit section and is selectively shiftable in at least one direction from a first position to a second position. A cylindrical wall is defined on the casing conduit section and has inner and outer surfaces. The wall, upon perforation thereof within the well, provides fluid flow passageways therethrough for transmission of well fluids from the exterior of the casing conduit section to the interior thereof when the conduit section is within the subterranean well. Means are provided on the valve member for cooperation with an auxiliary shifting means for movement of the valve member from the first position to the second position for closing or opening the fluid flow passageways.

The method includes installation of the casing conduit section at the top of the well during makeup of the casing string, and running the string with the casing conduit section into the well to position the casing conduit section member adjacent the production zone. The casing conduit section then is perforated by conventional means, such as by wireline or tubing conveyed perforating gun to provide fluid flow passageways through the walls of the casing. Typically, the gun will be retrieved, and an auxiliary conduit, such as coiled tubing, will be introduced into the well through the casing string, and such auxiliary conduit will carry an auxiliary shifting means to cooperate with the means on the valve member to move the valve member from the first position to the second position for closing the fluid flow passageways. Thereafter, the auxiliary means will be retrieved from the well, and the production zone will be isolated from the interior casing and under control.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a longitudinal half sectional schematic illustration of a subterranean well with the apparatus of the invention in position prior to perforation of the casing conduit section.

Fig. 2 is a view similar to that of Fig. 1 illustrating perforation of the casing conduit section.

Fig. 3 is a view similar to those of Figs. 1 and 2 showing the casing conduit section perforated, the gun retrieved, and the auxiliary shifting means in position to move the means on the valve member from a first position to close the fluid flow passageways.

Fig. 4 is an illustration of the auxiliary shifting means in position to shift a closing sleeve to isolate the perforations and close the fluid flow passageways. DESCRIPTION OF THE PREFERRED EMBODIMENT

Now referring to Fig. 1, there is shown a casing conduit string C positioned within a well W with a 6 workstring WS, which has been introduced into the well W subsequent to the running and cementing of the casing C in the well, with a packer P being disposed on the lowermost end of the workstring WS.

The packer P is shown as being set within the well W at a position longitudinally above but approximate to the uppermost end of a production zone PZ. A tubing section TS is carried at the lowermost end of the packer P with a tubing conveyed perforating gun PG secured at the lowermost end of the section TS. While a tubing conveyed perforating gun PG, which is well-known to those skilled in the art, is illustrated in the drawings and described in the perferred embodiments of this invention, it should be understood that other means of perforating the casing conduit section may also be utilized. For example, wireline perforating guns are easily utilized in the present invention.

A casing conduit section 10 is illustrated with a valve 11 interiorly disposed thereof. While the valve 11 is shown interiorly disposed of the casing conduit section 10, the valve 11 could be positioned exteriorly of the casing conduit section 10, and, in such instances, such valve 11 should be designed such that its shifting actuation is not adversely effected by the cementing of the casing C within the well W.

After the casing conduit section 10 is positioned adjacent the production zone PZ by the running of the 7 casing C, the workstring WS is introduced through the top of the well carrying the packer P and perforating gun PG. The gun PG is fired (Fig. 2) to provide fluid flow passageways through the cylindrical inner and outer walls 10c, 10d to provide perforations, or passageways, PF therethrough. Thereafter, the perforating means is withdrawn from the well, and an auxiliary conduit, such as coiled tubing CT, is introduced into the well to which is secured at its lower end a shifting tool ST.

Now referring to Fig. 4, the casing conduit section member 10 is secured at threads 12 to another casing conduit section forming a part of the casing string C thereabove and is also secured at threads 13 at its lowermost end to a collar CL.

The casing conduit section member 10 has upper and lower profiles 10a, 10b for selective receipt of an outwardly extending buttress 11d on a valve member 11 londitudinally disposed interiorly of the casing condui section 10. When the buttress 11d is positioned within the groove or profile 10a, the valve member 11 is restrained from longitudinal movement downwardly across the perforations PF. However, upon shifting of the valve member 11, described below, the abutment 11d will be forced out of the groove 10a and when positioned across the groove 10b will flex outwardly therein to limit further longitudinal downward travel of the sleeve 11, and, in such position, seal elements 11a, 11b t 8 provided circumferentially exteriorly around the upper and lower portions of the valve member 11 will respectively seal against the interior wall 10c of the conduit section member 10 to prevent fluid communication to the interior of the member 10.

Also, as shown in Fig. 4, the coiled tubing CT has secured at its lowermost end by threads 14, a shifting tool ST. The shifting tool ST-has an upper body portion 15 threadably secured at 14 to the coiled tubing CT thereabove and an inner control element 17 secured at threads 16 to the body member 15. Spring elements 18a, 18b are housed within the member 17 to urge a shifting sleeve 19 outwardly. When the shifting tool ST slides along the inner wall 10c of the casing conduit section member 10, the springs 18a, l8b will permit the member 19 to be biased outwardly and extend into a receiving profile Ile therefore on the valve member 11. Now, downward movement of the coiled tubing CT will transfer weight from the member 19 to the valve member 11. The abutment lld will come out of the upper groove 10a as the upper flexed portion llc of the valve member 11 flexes inwardly, and the shifting tool ST will carry the valve member 11 longitudinally downwardly within the casing conduit section member 10 until such time as the abutment lld is positioned in alignment with the lower groove 10b. Receipt of the abutment lld within the groove 10b will prevent further longitudinal travel of J 9 the sleeve 11. At such time, the seals 11a, 11b will bridge the perforations PF to close the fluid flow pas s ageways.

When it is desired to move the valve member 11 from the lowermost position, wherein the abutment 11d is within the groove 10b, back to the initial or opening position, a shifting tool ST designed to provide the member 19 into receipt into a companion upper shifting groove 11f will be introduced into the well on coiled tubing CT. Upward-pull on the coiled tubing CT subsequent to the spring biasing of the member 19 into the upper shifting groove 11f will move the sleeve 11 from the closed position across the perforations PF to the upper position, as shown in Fig. 4.

The shifting tool ST is generally described in Fig. 4 and may be of the general construction shown and described in co-pending application Serial No. 308,874 filed February 9, 1989, entitled "Method and Apparatus for Selectively Shifting a Tool Member", and assigned to the same assignee as the present application.

Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only and that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention.

Z, 11

Claims

CLAIMS:-

1. Method for completion of a subterranean well, comprising:

(a) assembling at the top of the well a casing conduit string comprising:

(1) a casing conduit section member insertable within said well and having means thereon at at least one end thereof for securement to the casing conduit string; (2) a valve member carried by said conduit section selectively shiftable in at least one direction from a first position to a second position; (3) a cylindrical wall defined on said casing conduit section and having inner and outer surfaces, said wall, upon perforation thereof within said well, providing fluid flow passageways therethrough for transmission of well fluids from the exterior of said casing conduit section to the interior thereof when said conduit section is within said subterranean well; and (4) means on said valve member for cooperation with an auxiliary shifting means for movement of said valve member from said first position to said second position for closing said fluid flow passageways; (b) running said casing conduit within said well and positioning said casing conduit section member adjacent to a production zone in said well; o 12 (c) introducing a perforating means through said casing conduit string and positioning said perforating means within said casing conduit section; (d) activating said perfoating means to perforate said cylindrical wall to provide fluid flow passageways therethrough; and (e) introducing through said casing conduit string an auxiliary shifting means and cooperating said shifting means with said means on said valve member to move said valve member from the first position to the second position to close said fluid flow passageways.

2. The method of Claim 1 further comprising the steps of:

(f) removing said shifting means from said well; and (g) introducing into said well an auxiliary shifting means to cooperate with said means on said valve member to move said valve member from said second position to said first position to open said fluid flow passageway.

3. Method for completion of a subterranean well, comprising:

(a) assembling at the top of the well a casing conduit string comprising:

(1) a casing conduit section member insertable -1 1 13 within said well and having means thereon at at least one end thereof for securement to the casing conduit string; (2) a valve member carried by said conduit section selectively shiftable in at least one direction from a first position to a second position; (3) a cylindrical wall defined on said casing conduit section and having inner and outer surfaces, said wall, upon perforation thereof within said well, providing fluid flow passageways therethrough for transmission of fluids when said conduit section is within said subterranean well; and (4) means on said valve member for cooperation with an auxiliary shifting means for movement of said valve member from said first position to said second position for closing said fluid flow passageways; (b) running said casing conduit within said well and positioning said casing conduit section member adjacent to a production zone in said well; (c) introducing a perforating means through said casing conduit string and positioning said perforating means within said casing conduit section; (d) activiating said perforating means to perforate said cylindrical wall to provide fluid flow passageways therethrough; and (e) introducing through said casing conduit string an auxiliary shifting means and cooperating said 14 shifting means with said means on said valve member to move said valve member from the first position to the second position to close said fluid flow passageways.

4. The method of Claim 3 further comprising the steps of:

z (f) removing said shifting means from said well; and (g) Introducing Into said well an auxiliary shifting means to booperate with said means on said valve member to move said valve member from said first position to said second position to close said fluid flow passageways.

Published 1990 a' The Patent Office.State House. 66 71 High Holborr.. Londcn"ATClR4TP-F-urther copies nikybeobtainedfrom The Peter., Office Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1187