US3347322A

US3347322A - Apparatus for well completion

Info

Publication number: US3347322A
Application number: US637011A
Authority: US
Inventors: Ii C P Lanmon
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1965-04-29
Filing date: 1967-05-08
Publication date: 1967-10-17
Anticipated expiration: 1984-10-17

Description

Oct. 17, 1967 7 c P LANMON n 3,347,322

APPARATUS FOR WELL COMPLETION Original Filed April 29, 1965 2 Sheets-Sheet 1 A 1 3 5.9 ae $7 47 22-1 AZ I C P lam/nor? ,I I INVENTOR.

BY Arr-a ar [Ill Oct. 17, 1967 C P LANMON H APPARATUS FOR WELL COMPLETION Original Filed April 29, 1965 2 Sheets-Sheet 2 f7; 0/? I [N VENTOR.

C/ 'Za United States Patent 7 Claims. (Cl. 175-452 ABSTRACT OF THE DISCLOSURE This application discloses a sealing member for use with well-completion apparatus. More particularly, the disclosed sealing member is arranged to maintain an effective fluid seal with a well bore wall whether the pressure in the isolated portion is greater than or less than the pressure exterior of the sealing member. To accomplish this, annular sealing members are concentrically arranged inside of and around a rigid annular member, with a support or the like being located adjacent to the rear of the sealing members and rigid member. The forward faces of the sealing members extend slightly beyond the forward end of the rigid member.

This application is a division of application Ser. No. 451,857, filed Apr. 29, 1965.

Accordingly, as will become apparent, this invention relates to apparatus for completing wells; and, more particularly, to apparatus for inhibiting the production of sand from unconsolidated or incompetent subsurface formations.

The present trend in well completion techniques is to rely upon only one or, at most, a very few perforations at each of carefully selected points in a well rather than indiscriminately scattering a large number of perforations along a wide interval. Where such perforations are made in a particularly loose or unconsolidated formation, sand particles and the like, will, however, be displaced into the well bore as connate fluids are produced from the formation. Thus, unless preventative measures are taken, these sand particles will either settle out so as to eventually fill the well bore or be carried to the surface by the produced fluids and severely damage production equipment. Moreover, with only a few perforations alfordin g limited entry through the casing into the formation, the production will be severely limited should any of these perforations become plugged.

Accordingly, to solve this problem, apparatus and methods have been devised whereby as soon as a loose formation is perforated, a suitable bonding or consolidating agent is injected through the perforation into the formation where, in time, it will react and harden. These agents, or so-called plastics generally coat the sand grains and thereby cementthem together. Although it will depend upon the particular agents employed, the pore spaces between adjacent particles are left open in one way or another so as to provide permeability. Thus, a portion of the formation surrounding the perforation is consolidated to serve as a porous support to prevent loose sand particles from entering the perforation as connate fluids are produced from the formation.

Typical of such treating agents, apparatus and methods are those disclosed in Patent No. 3,153,449 granted to Maurice P. Lebourg and No. 3,174,547 granted to Roger Q. Fields. As described in those patents, a perforatingand-injecting tool is positioned adjacent a formation that is believed to be unconsolidated. An extendib'le wall-engaging member is operated to shift the tool toward one wall of the casing and sealingly engage a sealing member on the opposite wall to isolate a portion of the. well bore 3,347,322 Patented Oct. 17, 1967 from the well control fluids. A perforator, such as a shaped charge, is then actuated to produce a perforation through this isolated portion into the adjacent earth formation. Thereafter, a bonding agent is ejected from a cylinder in the tool by a displacing piston and injected through the perforation into the formation.

Accordingly, it is an object of the present invention to provide new and improved apparatus for use in consolidating incompetent earth formations.

It is a further object of the present invention to provide sealing means for isolating a surface of an earth formation traversed by a well bore and maintaining an effective fluid seal around that surface regardless of whether the pressure acting on the exposed surface is greater or less than the pressure within the well bore exterior of the sealing means.

The apparatus of the present invention is comprised of a support member having a rigid, tubular projection therefrom with first and second annular, resilient sealing members respectively received within the tubular projection and mounted around the tubular projection. As will be subsequently described in detail, therefore, the sealing means of the present invention will maintain a fluid-tight seal regardless of whether the pressure exterior thereof is greater or less than that inside of the sealing member.

The novel features of the present invention are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation together with further objects and advantages thereof, may best be understood by way of illustration and example of certain embodiments when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view depicting a well-completion tool within a well bore and in position to consolidate an earth formation;

FIG. 2 is an elevational View, of a portion of the tool a preferred embodiment present invention; and

FIGS. 35 are views depicting in sequence the apparatus of FIG. 1 performing a typical formation-consolidation operation.

Turning now to FIG. 1, a we'll-completion tool 10 arranged to consolidate earth formations is shown suspended from a multi-conductor cable 11 in a casing 12 secured within a borehole 13 by a column of cement 14. The cable 11 is spooled from a winch (not shown) at the earths surface, with some of its conductors being arranged for selective connection to a power source (not shown) and others being connected to indicating-and-recording means (not shown) at the surface of the ground.

The well-completion tool 10 is comprised of an elongated body which, to facilitate manufacture and assembly, may be arranged to include upper and

lower sections

15 and 16 that are tandemly connected above and below partially in cross-section, depicted in FIG. 1 and showing of the sealing member of the an intermediate section 17 having longitudinally spaced,

annular, sealing means 18 and 19 on one side thereof and extendible wall-engaging means 20 on its opposite side.

The upper section 15 encloses a hydraulic system (not shown) for selectively actuating the extendible wall-engaging means 20. This hydraulic system may, for example, be of the type illustrated in Patent No. 3,011,554 granted to Robert Desbrandes which utilizes the hydrostatic pressure of the well control fluids 21 to develop an increased pressure in the system for selectively actuating the wallengaging means 20. Thus, upon command from the surface, the wall-engaging means 20 will be extended against one side of the casing 12 to shift the tool 10 laterally and sealingly engage the sealing means 18 and 19 against the opposite side of the casing. Then, when it is desired to retrieve the tool It the hydraulic pressure in the system is relieved and the wall-engaging means 20 retracted.

The hydraulically actuated wall-engaging means 21 are comprised of one or more extendible pistons 22 that support a back-up shoe 23 that is normally held in a retracted position against the section 17 by springs 24. The pistons 22 are sealingly received within hydraulic cylinders (not shown) that are connected to the hydraulic system. Thus, whenever the hydraulic system is activated from the surface, the developed hydraulic pressure will urge the pistons 22 outwardly to extend the back-up shoe 23 against the casing 12. Inasmuch as the particular details of the hydraulic system and wall-engaging means are not necessary for fully understanding the present invention, they have been shown only schematically in FIG. 1.

Fluid-discharge means are generally housed in the intermediate section 17 and include a pair of

lateral chambers

25 and 26 within the section that are each open at one end, with the annular sealing means 18 and 19 being mounted around the open ends of these chambers to provide

central openings

27 and 23. The lower chamber 26 is connected to a fluid passage 29; and thin-

walled closure members

30 and 31 are mounted in the chamber on each side of the open upper end of the passage 29 to block the central opening 28 and the rearward portion of the chamber. A shaped charge 32 is received in the rearward portion of the chamber 26 and faces the

closure members

30 and 31 so that, upon detonation, the perforating jet will puncture the closure members and be directed through the central opening 28.

In a similar manner, the upper chamber 25 is connected by a fluid passage 33 to an enclosed low-pressure or atmospheric chamber 34 in the intermediate section 17. Thin-walled closure members 35 and 36 are mounted in the upper chamber 25 on each side of the open lower end of the passage 23 to block the central opening 27 of the sealing means 18 and the rearward portion of the chamber. A shaped charge 37 is disposed in the rear of the upper chamber 25 and directed toward the closure members 35 and 36 so that, upon detonation, the perforating jet will pierce the closure members and be directed through the central openings 27. Suitable electrically responsive igniter means 38 and 39 (FIG. 2), that are ignitable from the surface of the earth via conductors in the cable 11, are connected to the

shaped charge

32 and 37.

It will be realized that when the lower shaped charge 32 is detonated to puncture the

closure members

30 and 31 and produce a perforation into an adjacent earth formation, fluid communication will be established from the fluid passage 29 through the central opening 2 and into the resultant perforation. Similarly, whenever the other shaped charge 37 is detonated, the closure members 35 and 36 will be pierced and fluid communication will be established from the resultant perforation through the central opening 27 and into the low-pressure chamber 34.

A treating-agent cylinder 40 is formed in the lower section 16 and connected by a centrally located passage 41 to a normally-open valve 42 (such as that shown at 105 in the above-mentioned Desbrandes patent) connected to fluid passage 29. The treating agent injector 43 for the cylinder 40 is comprised of a slidable, hollow cylinder 44 that has a closed lower end 45 and is telescoped over a piston 46 secured through an elongated coaxial rod 47 to the upper end of the treating-agent cylinder 40 and slidably received in the treating-agent cylinder. An annular piston 48 secured to the upper end of the slidable cylinder 44 is fluidly sealed by O-rings 49 and 50 to the inner wall of the treating-agent cylinder 40 and elongated rod 47, respectively, to isolate the treating agents in the cylinder 40' above the annular piston. An O-ring 51 fluidly seals the fixed piston 46 to the inner wall of the hollow cylinder 44 to provide an enclosed low-pressure or atmospheric chamber 52 therein below the fixed piston. A port 53 is provided in the wall of the hollow cylinder 44 to admit well control fluids 21 into the space 54 below the annular piston 48 and above the fixed piston 46.

The treating-agent cylinder is divided into separate fluid-tight chambers 5557 by spaced, floating

pistons

58 and 59 that are each fluidly sealed between the elongated rod 47 and inner wall of the cylinder 40. As will be subsequently explained, valves 60 and 61 (such as those in FIG. 3 of the Fields patent) in the annular

floating pistons

58 and 59 remain closed to segregate the treating agents in the chambers 55-57 until each

piston

58 and 59 has reached its upper limit of travel. A flow restrictor 62 is placed in series with the valve 60 to regulate the flow of treating agents from the intermediate and

lower chambers

56 and 57. 7

It will be appreciated that when the cylinder 40 is filled with treating agents, the hollow cylinder 44 and annular piston 48 will remain in the position illustrated in FIG. 1 until the thin-walled closure member 31 is punctured. Thus, until the shaped charge 32 is detonated, the forces tending to move the hollow cylinder 44 and piston 48 upwardly must equal the forces acting downwardly thereon. Since each of these forces is equal to the product of a pressure multiplied by the effective cross-sectional area that it acts upon, by reference to FIG. 1, the forces can be expressed as:

It will be appreciated that (A A will be very nearly equal to A and that P will be practically negligible. Thus, it will be realized that the pressure developed (P in treating-agent cylinder 40 will be very nearly double the hydrostatic pressure (P of the well control fluids 21. Accordingly, if for example, the ratio of developed and hydrostatic pressures is in the order of 1.8:1 and the hydrostatic pressure is 10,000 p.s.i.g., it will be appreciated that the injection pressure will be 18,000 p.s.i.g. Thus, if the natural formation pressure is 9,000 p.s.i.g., the treating agents in the cylinder 40 will be injected at an effective differential of 9,000 p.s.i.

Accordingly, the hydrostatic pressure of the well control fluids 21 will act on the injector 43 to exert a multiplied pressure on the treating agents in the chambers 55 57 to sequentially discharge the treating agents from the chambers through the fluid passage 41 thereabove. This multiplied pressure produces a high effective differential pressure relative to formation pressures.

A pressure transducer 63 is provided to continuously monitor the pressure in the fluid passage 29. This transducer 63 may, for example, be of the type shown in FIG. 9 of the aforementioned Desbrandes patent, and is connected by an electrical lead (not shown) via the cable 11 to the pressure indicating-and-recording apparatus at the surface of the earth. Thus, by observing the variations in pressure measurements, an operator will be advised of the progress of the operating cycle of the well-completion tool 10. 2

Turning now to FIG. 2, an elevational view, partially in cross-section, is shown of one manner in which the intermediate section 17 may be arranged with the sealing means 18 and 19 of the present invention and with reference numerals used in conjunction with FIG. 1 to identify the corresponding elements.

Shaped charge chambers

25 and 26 are formed in the intermediate section 17 and tilted in such a manner that their central axes intersect a short distance in front of the forward ends of the chambers. The shaped

charges

32 and 37 are secured and fluidly sealed in the

chambers

26 and 25 behind threaded

tubular members

64 and 65 having

enlargeddiameter flanges

66 and 67 on their forward end. The

flanges

66 and 67 support annular elastomen'c sealing members 68 nad 69 that are received within forwardly facing counterbores 70 and 71 in the section 17 and fluidly sealed therein by O-rings 72 and 73. O-rings 74 and 75 around the central portion of the

closure members

64 and 65 provide fluid-tight

annular spaces

76 and 77 in the forward end of the

lateral chambers

25 and 26, with

radial bores

78 and 79 connecting these spaces to the

central bores

80 and 81 through the closure members.

The sealing

members

68 and 69 are comprised of concentrically arranged outer and inner elastomeric rings 82-85 mounted on opposite sides of annular reinforcing

members

86 and 87. Shoulders 88 and89 directed inwardly from the rear of the reinforcing

members

86 and 87 are secured against the forward faces of the

tubular members

64 and 65 by the forward thin-

walled closure members

31 and 36. The forward faces 90 and 91 of the sealing means 18 and 19 are skewed in the vertical plane and curved in the horizontal plane to insure that they will conform to the curvature of a casing or borehole wall. It will be appreciated that the reinforcing

rings

86 and 87 Will prevent the outer elastomeric rings 82 and 84 from 'bein g extruded radially inwardly whenever the hydrostatic pressure of the well control fluids 21 is greater than the pressure within the

central openings

27 and 28. Similarly, the inner elastomeric rings 83 and 85 will be supported against radial outward extrusion whenever the pressure within the

central openings

27 and 28 is greater than that of the well control fluids 21.

The thin-walled closure members 35 and 36 are spaced apart and threadedly secured in the central bore 81 through the upper tubular member 65 on opposite sides of the radial bores 79 to block the central opening 27 and isolate the shaped charge 37. The fluid passage 33 connects the bore 81 between the thin-walled closure members 35 and 36 to an enlarged bore 92 thereabove that is closed at its upper end to provide the atmospheric chamber 34. The detonating means 33 for detonating the shaped charge 37 are comprised of a short length of detonating cord 93 disposed on the rear of the shaped charge 37 that is coupled to a conventional electrical detonator 94 received within a transverse passage 95 extending upwardly from the shaped charge chamber 25. The other thin-

walled closure members

30 and 31 are arranged in the same manner and define a space in the central bore 80 of the lower tubular member 64 that is connected by a fluid passage 96 to the main fluid passage 29 in the lower section 16 (FIG. 1). The shaped charge 32 is similarly detonated in the same manner by the detonating means 38 comprised of a detonating cord 97 and electrical detonator 98. The hydraulically actuated pistons 22 are mounted in hydraulic cylinders at each end of the section 17, with the back-up shoe 23 being normally retracted against the rear face of the section 17.

Turning now to FIGS. 35, the successive steps of a formation-consolidation operation are schematically illustrated as they would be performed by the well-completion tool 10. Although the exact arrangement will, of course, be determined by the particular consolidating materials to be used by way of example, a pre-flush fluid 99, such as a saline solution, is contained in the upper chamber 55 of the treating-agent cylinder 40; the intermediate chamber 56 contains a suitable plastic consolidation agent 100, such as a formaline-cresol mixture, while the lower chamber 57 contains an after-flush agent 101 such as kerosene. Other consolidating agents and associated reagents that may be used would include those described in U.S. Patents Nos. 3,070,161, 3,097,692, and 3,100,527.

After the treating agents 99-101 have been deposited in the cylinder 40, the tool is assembled and positioned in the well bore 13 adjacent a selected formation 102. By actuating the hydraulic system, the back-up shoe 23 is extended to shift the tool laterally and sealingly engage the sealing means 18 and 19 against the casing 12. Once the sealing means 18 and 19 have been firmly seated, it will be appreciated that the

central openings

27 and 28 in front of the thin-

walled closure members

31 and 36 will be isolated from the well control fluids 21 in the well bore 13. At this time, the hydrostatic pressure of the well con- 6 trol fluids 21 will have displaced the pre-fiush fluid 99 from the upper chamber 55 through the normally-open valve 42 and into the space in bore between the

thinwalled closure members

30 and 31.

As best seen in FIG. 3, the lower shaped charge 32 is then detonated to puncture the thin-

walled closure members

30 and 31 and produce a perforation 103 that is directed into the formation 102 in a slightly upward direction. As the perforating jet punctures the closure member 31, the pre-flush fluid 99 (which is at a high effective differential pressure relative to the pressure of the formation fluids) will be immediately displaced into the perforation 103. As the pre-flush fluid is exhausted from the upper chamber 55, it Will be realized that the full pressure developed in the treating cylinder 40 by the injector 43 will be available to inject this agent at a high flow rate into the formation 102. Thus, by injecting the preflush fluid 99 into the formation 102 at this elevated pressure, the agent will be able to break through any residue left in the perforation 103 by the shaped charge 32 and enter the formation.

It will be appreciated that although the fluid pressure within the central opening 28 is higher than the hydrostatic pressure of the well control fluids 21, the forward end of the reinforcing member 86 will be against the casing 12 and sealing member 83 will be sealed there with. However, the reinforcing member 86 will support the sealing member 83 of the present invention and prevent its radially outward extrusion.

As best seen in FIG. 4, once the pre-fiush fluid 99 has been expelled from the upper chamber 55, the upper floating piston 58 will have reached the top of the cylinder 40 to open the valve 60 therein. Then, the continued application of the developed pressure by the injector 43 will displace the remaining treating agents 100 and 101 in controlled sequence from the intermediate and

lower chamber

56 and 57 through the flow restriction 62 and into the formation 102. As these other treating agents 100 and 101 are injected into the formation 102, the consolidation plastic agent 100 will harden and, in time, consolidate the loose formation.

, Once the treating agents 99-101 have been exhausted, the tool 10 is left in position, as seen in FIG. 4, for a period of time calculated to be sufiicient for the plasticconsolidating material to have sufficiently firmed or congealed to form a porous barrier, as at 104, around the perforation 103. This interval of time will, of course depend upon the setting characteristics of the particular plastic employed. Then, once the plastic agent is calculated to have firmed or hardened, as best seen in FIG. 5, the upper shaped charge 37 is then detonated to produce a second perforation that either intersects the first perforation 103 or comes in close proximity thereto. It will be appreciated that by perforating into the firmed or hardened porous portion 104 of the formation 102, the perforation 105 will not collapse. Moreover, fluid communication will be suddenly established through the second perforation 105 to the atmospheric chamber 34. Thus, by suddenly opening communication from the formation 102 to the atmospheric chamber 34, the formation pressure will displace the connate fluids into the perforation 105 and up into the atmospheric chamber and flush the debris from within the perforation to leave a relatively uncontaminated and stabilized surface. It will be realized, of course, that a conventional normally-closed valve could also be employed in passage 33.

It should be noted that the sudden drop in pressure within the

central openings

27 and 28 of sealing means 18 and 19 will cause the outer sealing rings 84 and 82 to be tightly sealed against the casing 12 by the hydrostatic pressure. Tubular reinforcing

members

86 and 87 will, however, prevent extrusion of sealing rings 82 and 84 into the

central openings

27 and 28.

Once the operation has been completed, the hydraulic system is actuated to relieve the hydraulic pressure therein to retract the backup shOe 23 and allow the tool 10 to be withdrawn from the well bore 13.

Thus, it will be appreciated that by employing the new and improved sealing means, such as at 18, of the present invention, an effective fluid seal will be maintained around the entry hole into the casing regardless of whether the fluid pressure in the central opening 27 is greater or less than the hydrostatic pressure of the well control fluids 21.

While a particular embodiment of the present invention has been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

What is claimed is:

1. As a s'ubcombination, a sealing pad for sealing against the wall of a well bore traversing earth formations comprising: an annular member having inner and outer Wall surfaces; inner and outer resilient sealing members respectively disposed on said wall surfaces, said sealing members having forward portions extending beyond a forward portion of said annular member; and means for supporting the rearward portions of said annular member and resilient members.

2. The sealing pad of claim 1 wherein said supporting means include: a base member carrying another portion of said annular member.

3. Appartaus for use in a well bore traversing earth formations comprising: a support; sealing means on said support for isolating spaced-apart sections of a well bore from one another and from fluids in the well bore, said sealing means having first and second openings therein and including a rigid annular member aligned with one of said openings and having inner and outer wall surfaces, inner and outer resilient members respectively disposed on said wall surfaces and having forward portions extending beyond a forward portion of said annular member, and means for supporting the rearward portions of said annular member and resilient members; means in said support for placing said sealing means into sealing engagement with a well bore; first and second perforating means on said support respectively directed toward said openings and adapted, upon operation, to pass through said openings and produce perforations in earth formations adjacent thereto; means on said support for discharging a fluid under a first pressure through the other of said openings and into one of such perforations; and means for receiving fluid from the other of such perforations through said annular member and said one opening including a fluid receiver on said support at a second pressure initially lower than the aforementioned first pressure.

4. The apparatus of claim 3 wherein said first and second perforating means are directed toward said open ings and adapted, upon operation, to pass therethrough and produce perforations approaching an intersection with one another in earth formations adjacent to said sealing means.

5. The apparatus of claim 3 wherein said sealing means include: a second annular member aligned with said other opening and also having inner and outer wall surfaces, second inner and outer resilient members respectively disposed on said wall surfaces of said second annular member and having forward portions extending beyond a forward portion of said second annular member.

6. The apparatus of claim 5 wherein said first pressure is greater than the hydrostatic pressure of fluids in a well bore.

7. The apparatus of claim 5 wherein said first and second perforating means are directed along axes calculated to approach an intersection beyond and in front of said forward portions of said inner and outer resilinet members.

References Cited UNITED STATES PATENTS 2,821,256 1/1958 Boller 4.52 X 3,174,547 3/1965 Fields 175-452 X 3,273,647 9/1966 Briggs et al 166-100 3,318,381 5/1967 Brandt 1754.52 X

ERNEST R. PURSER, Primary Examiner.

DAVID H. BROWN, Examiner.

Claims

1. AS A SUBCOMBINATION, A SEALING PAD FOR SEALING AGAINST THE WALL OF A WELL BORE TRAVERSING EARTH FORMATIONS COMPRISING: AN ANNULAR MEMBER HAVING INNER AND OUTER WALL SURFACES; INNER AND OUTER RESILIENT SEALING MEMBERS RESPECTIVELY DISPOSED ON SAID WALL SURFACES, SAID SEALING MEMBERS HAVING FORWARD PORTIONS EXTENDING BEYOND A FORWARD PORTION OF SAID ANNULAR MEMBER; AND MEANS FOR SUPPORTING THE REARWARD PORTIONS OF SAID ANNULAR MEMBER AND RESILIENT MEMBERS.