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Publication numberUS3316963 A
Publication typeGrant
Publication dateMay 2, 1967
Filing dateApr 27, 1964
Priority dateApr 27, 1964
Publication numberUS 3316963 A, US 3316963A, US-A-3316963, US3316963 A, US3316963A
InventorsBoldrick John S, Krause Jr Henry M
Original AssigneeExxon Production Research Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Repair of wells
US 3316963 A
Abstract  available in
Images(1)
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Claims  available in
Description  (OCR text may contain errors)

May 2 1967 J. s. BOLDRICK ETAL 3,316,963

REPAIR OF WELLS Filed April 27, 1964 wmammwa 2.55.21

INVENTORS. JOHN s. BoLoRlcK,

BY HENRY M- KRAUSE, JR.,

United States Patent litice 3,316,963 Patented May 2, 1967 Houston, Tex., to Esso Production Houston, Tex., a corporation of The present invention is directed to repairing a well. More particularly, t-he invention is concerned with a well operation wherein there has been subsidence of the ground or movement of the surface casing. In its more specific Iaspects, the invention is concerned with method and apparatus for repairing a well.

In the drilling of oil and gas wells, it is common practice to set a su-rface string of pipe which serves to protect shallow fresh water sands from contamination, provides a means for controlling the well during the deeper drilling operations, and supports the weight of subsequent strings of casing and tubing. If the well is completed, the oil or gas string is set inside this surface pipe. Mostly, the weight of the oil or gas string is supported on the wellhead on top of the surface pipe so that the oil or gas string is in tension and the surface pipe is in compression after the well is completed. Subsequent conditions can and have caused these loads to change. For example, subsidence of the surface formations can cause the surface pipe to drop. This is resisted by the oil or gas string which is fixed a-t its bottom and rigidly connected to the surface pipe at the surface wellhead. The end result is that the surface pipe stress tends to reverse from compression to tension and the stress on the oil or gas string reverses from tension to compression. These stress reversals can cause serious well problems such as leakage of thread connections, obstruction to passage of tools, and may even result in the failure of the casing strings. Heretofore, conditions resulting from earth subsidence and movement of the surface pipe have been corrected by using a conventional workover rig and killing the well. The wellhead was then separated and the oil or gas string pulled into tension, following which the excess oil or gas string pipe was cut and removed and the wellhead then reconnected.

In accordance with the present invention, problems due to subsidence of the earth and surface casing movement may be solved without using a conventional workover rig and without the necessity of removing the wellhead or breaking any of the wellhead seals. Thus, the present invention may be briefly described as a method of providing origin-al stress on a well having a wellhead arranged on a surface pipe and having a pipe string connected to the wellhead wherein original stress on the surface pipe and pipe st-ring is changed such as to be reversed. Thus, instead of the oil string being `in tension, it is in compression and rather than the surface casing being in compression, it is in tension. Where such a situation arises, in accordance with the present invention, compressive stress is applied to the surface pipe at a point below the wellhead. The surface pipe is then cut and separated between the wellhead and the point where stress is applied and thereafter the separated surface pipe ends are then sealingly joined whereby original stress is provided On both the `surface pipe and the pipe string.

In accordance with the present invention, after the surface pipe has been cut and separated, a section of split surface pipe is placed between the separated ends of the surface pipe, and then the separated ends and the section are welded together to extend the length of the surface pipe and to return the surface pipe to compression and the oil string to tension.

Alter-natively, reduction in compressive loading on surface pipe may be performed by removing a section of the surface pipe by cutting same and then pulling the ends of the surface pipe together and then sealingly joining them such as by wel-ding. Thus, in accordance with the present invention, the condition of changes in original stress may be corrected by employing apparatus which comprises or consists essentially of at least rst and second piston cylinders having a piston in each of the cylinders with a piston arm extending outwardly from the cylinders. A plurality of cylinders may be employed and in one operation four cylinders were actually used. The free end of each of the piston arms has a clamp for releasable connection to the wellhead. The opposite end of the piston cylinder has a hinged clamp which is adapted to be placed around the surface pipe, the hinged clamp being provided with means for maintaining it around the surface pipe, and with s-lip means for engaging with the surface pipe. By connecting the lclamp on the piston arms to the wellhead and by placing the hinged clamp around the su-rface casing, pressure may then be applied to the piston cylinder in either direction, as desired, to control or alter the relative positions of the hinged clamp and the clamp connected to the pistou arms. With this assembly installed, in applying pressure to the piston cylinders a compression load may ybe induced between the wellhead and the surface pipe so that the pipe may be safely cut by any means, such as with a cutting torch or by a mechanical cutter. In a tension load on the surface pipe, an excess of that induced by the piston cylinders is transferred to the piston cylinders when the surface pipe is cut. If, on the other hand, it is desired to induce tension loads into the oil string or pipe, iiuid pressure is applied so as to move apart the c-lamp attached to the wellhead and the clamp attached to the surface pipe until the desired load, as determined by the pressure applied, is obtained.

A split section of -surface pipe may be inserted and aligned in the resulting gap in Ithe surface pipe and welded in place or otherwise joined to the separated ends to become an integra-l part of the surface pipe string. When the hinged clamp assembly is released, the compression load is then carried by the s-urface pipe.

The technique of the present invention may also be used to reduce compressive loading in surface pipe if such should be desired and in this instance a section of the surface pipe would be removed after cutting same and pressure applied to pull the separated ends of the pipe together for rejoining, lsuch as by welding. i

Thus, the present invention is quite useful `and provides a safe and economica-l means of correcting reverse surface pipe stress in wells where subsidence of the earths surface or movement has caused a reversal or change in loading on lthe surface pipe and oil pipe string.

T-he present invention will be further described by reference to the drawing in which:

FIG. 1 illustrates the apparatus on the well with the stress of the surface pipe and oil string reversed;

FiG. 2 is a showing of the well after cutting the surface pipe, raising the wellhead and inserting a split section of surface pipe between the separated ends of the surface pipe; and

FIG. 3 is a showing of the repaired well.

Referring now to the drawing and specifically to FIG. 1, numeral 11 designates coacting piston cylinders having a piston 12 arranged therein attached to a piston arm 13. The free end of piston arm 13 is connected through a yoke 14 and pin 15 to a C-shaped clamp 16 which is provided with means, such as threaded bolts 17, for attachment t-o flanges 18 on the wellhead 19. A surface pipe or casing Ztl is also connected to the wellhead 19 and the hinged clamp 21, which is attached by yokes 22 and pins 23 to connecting member 24 and piston cylinder 11. The hinged clamp 21 is provided with double slips 25 which bite into the external surface of the surface pipe 20. Hinged clamp 21 is also provided with threaded bolts 26 to maintain the hinged clamp 21 around the surface pipe 20, the threaded bol-ts being arranged in openings of anges 27 on the hinged clamp 21.

It is to be noted that an oil or pipe string 28 is arranged concentrically within the surface pipe 20 and a second pipe string 29 is also arranged concentrically within the oil pipe string 28. These strings are connected to and are sealed with the wellhead 19 and ordinarily are suspended therefrom such that the oil string 28 and pipe string 29 are in tension. It is to be noted that the surface pipe or casing 20 is arranged within the well bore 30 drilled from the earths surface 31 and cemented in place with cement 32. The oil pipe string 28 is fixed at the bottom of the well, such as with a packer, or cemented in the well and is rigidly connected to the surface pipe through the wellhead 19.

In FIG. l, it may be assumed that there has been earth subsidence and the surface pipe 20 is in tension which, in turn, results in the oil pipe string 28 being in compression rather than the opposite, which is normally true. Hydraulic pressure is exerted on the pistons 12 through hydraulic lines 33 and 34 from a source of hydraulic fluid (not shown) as a safety measure. A pressure gauge 35 is connected to hydraulic line 33 to register the pressure exerted downwardly on pistons 12. In accordance with the present invention, with the apparatus illustrated in place, the surface casing 20 is cut at a point C below the wellhead 19 and between the wellhead and the clamp 21.

The wellhead 19 is then raised, as shown in FIG. 2, by applying force on the pistons 12 from the opposite direction, as will be described, to cause a separation in the surface pipe 20 and to provide a space 39 for insertion of a section 40 of split surface pipe in the space 39.

The raising operation is accomplished by injection of hydraulic fluid under a sufficient pressure from a source (not shown) below the pistons 12 through lines 36 and 37, pressure being indicated on pressure gauge 38. This provides for separation of the surface casing 20 and provides a space 39, as has been described, into which the sections 49 of split surface pipe may be inserted. With the surface casing in compression and the oil pipe string in tension, the clamps 16 and 21 may be removed after the sections 40 have been sealingly joined into the surface pipe 20, such as by welding, with welds 41. The well assembly, in its repaired condition, with the surface pipe 20 in compression and oil string 28 in tension, is shown in FIG. 3.

If it is desired to remove a section of the surface pipe 20, stepwise the procedure would be reversed proceeding from FIG. 3 to FIG. 2 and to FIG. 1, rather than the opposite as has been described. In this instance, with the Well in a condition as shown in FIG. 3, the apparatus would be placed on the well as shown in FIG. 2 and cuts would then be made on the lines of the welds 41 in FIG. 3 and the section 40- would be removed as shown in FIG. 2. Then the separated ends of the cut surface pipe 20 would be pulled together with the apparatus, as described, by applying uid pressure through lines 33 and 34 against the piston 12. The ltwo ends would then be sealed together by welding at the point C as shown in FIG. 1.

It will be seen from the foregoing description taken with the drawing that a mode and apparatus have been provided by way of which oil and/ or gas wells may be repaired without requiring the killing of the Well and the breaking of the wellhead seals; thus, the present invention is quite advantageous and useful.

The nature and objects of the present invention having been fully described and illustrated and the best mode and embodiment thereof set forth, what we wish to claim as new and useful and secure by Letters Patent is:

1. A method of providing stress on a well having a Wellhead arranged on a surface pipe and having a pipe string connected to the wellhead and wherein the stress on said surface pipe and pipe string is changed which comprises applying stress to said surface pipe at a point below the wellhead, cutting and separating said surface pipe between the wellhead and said point and then sealingly joining the ends of said separated surface pipe whereby stress is provided on both said surface pipe and pipe string.

2. A method of providing stress on a well having a wellhead arranged on a surface pipe and having a pipe string connected to the wellhead and wherein the normal stress on said surface pipe and pipe string is changed which comprises applying stress to said surface pipe at a point below the wellhead, cutting and separating said surface pipe between the wellhead and said point, inserting between the separated ends of said surface pipe a section of pipe sufficient to extend the length of said surface pipe and to maintain the applied stress, and then sealingly joining the ends of said separated surface pipe to said section whereby normal stress is provided on both said surface pipe and pipe string.

3. A method of providing stress on a well a having a wellhead arranged on a surface pipe and having a pipe string connected to the wellhead and wherein the stress on said surface pipe and pipe string is changed which comprises applying stress to said surface pipe at a point below the wellhead, cutting and separating said surface pipe between the wellhead and said point, removing a section of said cut surface pipe, and then sealingly joining said separated surface pipe after removal of said section whereby stress is provided on both said surface pipe and pipe string.

4. A method of providing original stress on a well having a wellhead aranged on a surface pipe and having a pipe string connected to the wellhead and wherein the original stress on said surface pipe and pipe string is changed which comprises applying stress to said surface pipe at a point below the wellhead, cutting and separating said surface pipe between the wellhead and said point and then welding the ends of said separated surface pipe whereby original stress is provided on both said surface pipe and pipe string.

5. A method of providing original stress on a well having a wellhead arranged on a surface pipe and having a pipe string connected to the wellhead and wherein the original stresson said surface pipe and pipe string is changed which comprises applying stress to and supporting said surface pipe at a point below the wellhead, cutting and separating said surface pipe between the wellhead and said point7 sealingly joining said separated surface pipe, and releasing support from said surface pipe whereby original stress is provided on both said surface pipe and pipe string.

6. A method of providing stress on a well having a wellhead arranged on a surface pipe and having a pipe string connected to the wellhead and wherein the stress on said surface pipe and pipe string is reversed which comprises applying stress to said surface pipe at a point below the wellhead, cutting said surface pipe between the wellhead and said point, raising the upper end of said cut surface pipe, inserting between the lower and upper ends of said cut surface pipe a section of pipe of sufiicient length to extend the length of said surface pipe and to maintain the applied stress, and then sealingly joining the ends of said separated surface pipe to said section whereby the desired stress is provided on both said surface pipe and pipe string.

7. A method of providing stress on a well having a wellhead arranged on a surface pipe and having a pipe string connected to the wellhead which comprises applying stress to said surface pipe at a point below the wellhead, cutting said surface pipe between the wellhead and said point, raising the upper end of said cut surface pipe, removing a section of said cutsurface pipe, lowering the upper end of said surface pipe, and then sealingly joining the ends of saidseparated surface pipe after removal of said section whereby the desired stress is provided on both said surface pipe and pipe string.

References Cited by the Examiner UNITED STATES PATENTS 1,982,835 12/1934 Stampi et a1. 254-30 2,126,933 8/1938 Stone et al. 254-29 6 Carruthers 61-46.5 Grant et al. 254-93 Hubby 166--75 Brown 166-49 X CHARLES E. OCONNELL, Primary Examiner.

JAMES A. LEP'PINK, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1982835 *Jul 1, 1933Dec 4, 1934V U WilliamsDrill steel puller
US2126933 *Aug 12, 1935Aug 16, 1938Hydril CoWell drilling equipment
US2352370 *Dec 6, 1940Jun 27, 1944Robert L CarruthersDerrick support for underwater drilling
US2967400 *Aug 8, 1955Jan 10, 1961Grant James IMethod and apparatus for erecting offshore platform
US3166125 *Nov 20, 1961Jan 19, 1965Texaco IncAdjustable casing head
US3180617 *Oct 17, 1963Apr 27, 1965Brown Oil ToolsWellhead elevating device
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3581817 *Mar 13, 1969Jun 1, 1971Baker Oil Tools IncTensioned well bore liner and tool
US3738426 *Feb 16, 1971Jun 12, 1973Rockwell Mfg CoSubsidence wellhead assembly and method
US4595062 *Jul 17, 1980Jun 17, 1986Varco International, Inc.Well casing jack mechanism
US4681173 *Jul 19, 1985Jul 21, 1987Texaco Inc.Method and apparatus for drilling a group of subsea wells
US4890671 *Jan 9, 1989Jan 2, 1990Baxter Bill VPolished rod liner puller assembly
US4974676 *Jun 9, 1989Dec 4, 1990Duhn Oil Tool, Inc.Ground subsiding wellhead
US5121793 *Apr 2, 1990Jun 16, 1992Societe Nationale Elf Aquitaine (Production)Capping equipment for blowout well
US5205356 *Oct 7, 1991Apr 27, 1993Abb Vetco Gray Inc.Well starter head
US6189620 *Jul 31, 2000Feb 20, 2001Mcdowell Bobby DewainMethod and apparatus for shutting off upward flow from a conduit
US6401811 *Apr 24, 2000Jun 11, 2002Davis-Lynch, Inc.Tool tie-down
US6488094 *Jul 25, 2001Dec 3, 2002Delmc, Inc.Method and apparatus for shutting off upward flow from a conduit
US6997260 *Mar 6, 2003Feb 14, 2006Bruce TraderMethod of repairing tubular members on oil and gas wells
DE2224151A1 *May 17, 1972Dec 7, 1972 Title not available
DE3025209A1 *Jul 3, 1980Jan 28, 1982Beb GewerkschaftenSelbstaendig regelnder schwingungsdaempfer an sondenkopf
Classifications
U.S. Classification166/298, 254/93.00R, 254/30, 166/379, 166/85.1, 166/277
International ClassificationE21B29/00, E21B29/10
Cooperative ClassificationE21B29/10
European ClassificationE21B29/10