US3697114A

US3697114A - Device for gripping elongated members

Info

Publication number: US3697114A
Application number: US97884A
Authority: US
Inventors: Michel Chatard; Pierre Grolet; Remi Reynard
Original assignee: IFP Energies Nouvelles IFPEN
Current assignee: IFP Energies Nouvelles IFPEN
Priority date: 1970-12-14
Filing date: 1970-12-14
Publication date: 1972-10-10
Anticipated expiration: 1989-10-10

Abstract

Device used for withdrawing from a well a section of drill string wedged therein. The device includes a rod ending with a prolonging member containing a sock-like member adapted to cap said drill string section and to contract under the effect of a longitudinal traction force applied thereto while raising said rod, thereby gripping the drill string section as a result of the friction force generated by said contraction.

Description

United States Patent Chatard et al.

[54] DEVICE FOR GRIPPING ELONGATED MEMBERS [72] Inventors: Michel Chatard, Chatou; Pierre Grolet, Montesson; Remi Reynarcl, Viroflay, all of France [73] Assignee: Institut Francais Du Petrole Des Carburants Et Lubrifiants, Rueil I58] Field of Search 294/86, 86 CG, 86.1, 86.14, 294/86.15, 86.26, 86.32; 174/84 [56] References Cited UNITED STATES PATENTS r,

1,521,789 l/l925 Oswald ..294/86.26

21 l 91 I 01 I 01 I 0| 51 Oct. 10, 1972 2,434,358 l/ 1948 Frank ..l74/84 Primary Examiner-Even C. Blunk Assistant Examiner-Johnny D. Cherry Attorney-Craig, Antonelli & Hill [57] ABSTRACT Device used for withdrawing from a well a section of drill string wedged therein. The device includes a rod ending with a prolonging member containing a socklike member adapted to cap said drill string section and to contract under the effect of a longitudinal traction force applied thereto while raising said rod, thereby gripping the drill string section as a result of the friction force generated by said contraction.

l 1 Claims, 6 Drawing Figures

mini sum

1 or 3 FIG.1A

f 00 t Ma PATENTEDncI 10 I972 wax SHEET 2 [IF 3 1114 1 DEVICE FOR GRIPPING ELONGATED MEMBERS This invention relates to a device for gripping an elongated member, particularly useful for withdrawing said member from a location where it is difficult to access.

In the following there will be referred, by way of non limitative example, to the fishing of a portion of drill string, e.g., formed of rigid drill stems used in rotary drilling, or a section of flexible pipe when drilling with a bottom motor suspended therefrom.

During drilling operations it may happen that a breakage of the drill string occurs. A lower portion of the drill string at the end of which is secured the drilling tool is thus lost in the well and it is practically impossible to restart the drilling operation as long as this lower portion of the drill string has not been removed.

It is thus necessary to conduct fishing operations for recovering the lower portion of the drill string. These operations are often difficult to carry out and are the more expensive as they also immobilize the drilling installation for a long time.

The fishing devices used up to now are very complex and require cutting off sections, on the portion of drill string to be recovered. This results in a further increase of the operation time and of its cost.

It is therefore an object of this invention to provide a simple device avoiding the above-mentioned disadvantages and which is efficient and easy to use.

A device according to the invention for gripping an elongated member wedged in a well, comprises: in combination, an an operating rod having one end which is adapted to be introduced into the well, a prolonging member for said rod at said end, said prolonging member being made solid with said rod and comprising internally a sock-like member or sock formed of a netting of wires, metal cables or strands, the two ends of said sock being respectively secured on said prolonging member and on said operating rod, said sock being adapted to cap the elongated member, means for disengaging said prolonging member from said operating rod and means for constricting said sock on the elongated member for ensuring the gripping thereof. The means for disengaging using relative axial displacement of the prolonging member and the operating rod for carrying out its function.

The invention will be better understood and further advantages thereof made apparent from the following description of a non-limitative embodiment illustrated in the accompanying drawings wherein FIGS. 1 A and 1 B respectively illustrate the upper and the lower portion of the device; and

FIGS. 2 A, 2 B, 3 A and 3 B illustrate the operation of the device.

On FIGS. 1 A and 1 B the device according to the invention is indicated as a whole by reference 1. This device comprises a member in prolongation of an operating rod 14, formed in this embodiment of a very long tubular member 2 at the end of which is secured another tubular member 3 carrying the drilling tool 4 of the crown type. At the upper part of member 2 and above a shoulder l l is slidably mounted a hollow piston 5. Piston 5 is made solid with member 2, in the position shown in FIG. 1 A, through fingers 6 in engagement with orifices 7 provided in member 2.

Channels 10 establish a communication between the central bore of piston 5 and an annular space 20 formed between member 2 and piston 5 above shoulder l 1.

Fingers 6 are maintained engaged in orifices 7, against the counter action of springs 8, by means of a sleeve 9 slidable in the bore of piston 5. This sleeve 5 is maintained at its uppermost position by a spring 12 which bears respectively on an internal shoulder of the bore of piston 5 and on a shoulder of sleeve 9. In this position the sleeve 9 obstructs orifices 10. This sleeve 9 is provided with a port hole 10a and grooves 13 for purposes which will be made apparent hereinafter.

In its uppermost position (FIG. 1 A) the sleeve 9 comes in abutment against the operating rod 14. This rod 14 from which is suspended the device 1 is made solid with piston 5, through a threaded connection.

At the lower part of piston 5 is anchored, by any convenient means, a sheath or sock-like member 15. This sock-like member is formed of a netting of wires, cables or strands. When this sock is not subjected to any axial tensile stress, it has an external diameter equal to the internal diameter of tubular member 2. This sock member 15 has an internal diameter greater than the external diameter of the drill string 16 to be withdrawn from the well. This sock-like member 15 is anchored at its lower part on tubular member 3. The weaving of this sock-like member is such that a very substantial decrease of its diameter is obtained when it is subjected to axial tensile stresses.

A centering device 17 comprising at its upper part a frusto-conical element is maintained in member 3 by means of shear pins 18.

When after breaking of the drill string it is desired to recover the lower part 16 thereof remaining in the well 19, the operation is as follows.

The device 1 is introduced, while driven in rotation through the rod 14, into the well 19. The tool 4 bores a hole of the well enabling the device 1 to cap the drill string 16. During this stage of the process the drilling fluid circulates through the central duct of pipe 14, as indicated by the arrows in FIGS. 1 A and 1 B. This fluid irrigates the drilling tool 4, thus making easier its boring action.

In the case where the drill string 16 is a flexible pipe formed of a tubular core coated with a plurality of metal armourings, the guiding member 17 makes it possible to compress, at the level of the breaking, the armourings which might deviate from the drill string axis while protecting the sock-like member 15 against any deterioration.

When device 1 is in the position shown in FIGS. 1 A and 1 B a ball 22 is introduced into the bore of pipe 14. As it is apparent in FIG. 2 A, this ball comes to abutment on a seat arranged therefor in the hole of sleeve 9 and interrupts any circulation of drilling fluid.

An increase of the drilling fluid pressure then produces a lowering of sleeve 9 in the hole of piston 5 (FIG. 2 A) against the counter action of elastic return means such as spring 12. This movement is continued until the recess 13 registers with fingers 6. In this position, shown in FIG. 2 A, the fingers 6 which maintained the piston 5 solid with the tubular member 2 are disengaged from the latter by the action of repelling means such as the return springs 8 and by engagement into recess 13 make piston 5 solid with sleeve 9. The port holes or conduits a then register with conduits 10 thus establishing communication between the hole of sleeve 9 and the annular space 20. The drilling fluid than flows to said annular space 20 through port holes 10a and conduits 10 as shown by the arrow in FIG. 2 A.

The tubular member 2 and the piston 5 being no longer solid with each other as already stated, the drilling fluid pressure produces a lowering of member 2 with respect to piston 5. This movement, favored by the own weight of member 2, results in the shearing of the shear pins 18 on the one hand andin the lengthening of the sock-like member surrounding the drill string 16, on the other hand.

As shown in FIGS. 3 A and 3 B, the lengthening of the sock-like member 15 results in a very strong constriction being favored by the circulation of drilling fluid in the direction shown by the arrows in FIGS. 3 A and 3 B.

After the sock-like member has been placed and gripped onto the drill string 16 the latter is withdrawn by raising the rod 14, which is solidly threaded with piston 5, thereby increasing the tensile stress exerted on the sock-like member and increasing the constriction thereof onto the drill string 16.

The wires, cables or strands of the sock like member may be selected of a sufficient hardness so that under the effect of the tensile stress they become sealed in the external wall of the drill string 16. The sock-like member length in contact with the drill string 16 must be sufficient (in most cases in excess of approximately 10 yards) for resulting in a total friction force of the cable strands of the socklike member on the drill string to compensate the weight of the portion thereof which has to be withdrawn from the well.

What we claim is:

l. A device for the withdrawal of an elongated member wedged in a well comprising the combination of an operating rod, one end of which is destined to be introduced into the well, a prolonging member for said rod at said end thereof, said prolonging member being made solid with said rod, a sock-like member formed of a netting of metal wires, cables or strands, placed inside said prolonging member, the two ends of said sock-like member being respectively secured to said prolonging member and to said operating rod, said sock-like member being adapted to cap the elongated member, means for disengaging said prolonging member from said operating rod, and means for constriction of said sock-like member on said elongated member, insuring the gripping of the elongated member by axial displacement of the prolonging member with respect to the operating rod.

2. A device according to claim 1 wherein said operating rod and said prolonging member are provided with at least one device for making them solid with each other and formed with two latching elements respectively carried on said rod and said prolonging member, said latching elements consisting of at least one retractable finger and at least one clamping orifice for this finger and a slidable sleeve provided with a recess for the disengagement of said retractable finger, elastic means maintaining said sleeve to a position where it locks said retractable finger in a position of engagement with said clamping orifice against the counter action of a repelling device which tends to urge said finger back to a position of disengagement, said means for disengaging being adapted to make said sleeve slide up to a position of disengagement at which the disengagement recess registers with the retractable finger, so that the latter can be disengaged from its clamping orifice by the action of said repelling device.

3. A device according to claim 2 with an operating rod comprising an axial bore for the passage of pressurized fluid, wherein said operating rod and the slidable sleeve are each provided with at least one conduit registering with one another in said position of disengagement, thereby establishing a communication between said bore and an annular space arranged between said operating rod and said prolonging member and means adapted to obstruct said sleeve so as to displace the same, by the action of the fluid pressure against the counter action of elastic means, to a position of disengagement at which the flow of fluid in said annular space insures the axial displacement of the prolonging member with respect to said operating rod.

4. An arrangement for withdrawing an elongated member which is wedged in a bore open only at one end, said arrangement comprising: an operating rod having a lower end adapted to be lowered into said bore, a sock-like member having an inner diameter which contracts when the sock-like member is stretched and expands when the sock-like member is compressed, said sock-like member having an upper end fixed with respect to the lower end of the operating rod and a lower end in alignment with said elongated member when said operating rod is in said bore, said lower end portion of the sock-like member having an inner diameter greater than the outer diameter of said elongated member when said sock-like member is in a relatively unstretched condition, holding means for holding the lower end of said sock-like member a fixed distance from the lower end of said operating rod while the operating rod and sock-like member are being lowered over the elongated member, and disengaging means for disengaging the holding means so as to permit the lower end of said sock-like member to move with respect to said operating rod so that a portion of said sock-like member can grip the elongated member.

5. An arrangement according to claim 4, characterized in that said holding means includes means forming a rigid connection between said operating rod and the lower end of said sock-like member.

6. An arrangement according to claim 4, characterized in that said sock-like member is rigidly connected at its lowermost end to a sleeve surrounding the sock-like member and the lower end of said operating rod, said holding means including means for fixing the position of said sleeve with respect to the operating rod.

7. An arrangement according to claim 6, characterized in that a piston is arranged inside of said sleeve with an upper end of said piston rigidly attached to said operating rod, said holding means including spring biased pin means connecting said sleeve and piston.

8. An arrangement according to claim 7, characterized in that said releasing means includes fluid means operated by fluid flowing through said operating rod.

9. An arrangement according to claim 8, characterized in that said releasing means includes a ball selectively positioned in said operating rod for effecting top of the elongated member to be withdrawn.

1 1. An arrangement according to claim 6, characterized in that said disengaging means includes fluid means for forcibly sliding said sleeve with respect to said operating rod whereby positive gripping of the elongated member takes place.

* II l

Claims

1. A device for the withdrawal of an elongated member wedged in a well comprising the combination of an operating rod, one end of which is destined to be introduced into the well, a prolonging member for said rod at said end thereof, said prolonging member being made solid with said rod, a sock-like member formed of a netting of metal wires, cables or strands, placed inside said prolonging member, the two ends of said sock-like member being respectively secured to said prolonging member and to said operating rod, said sock-like member being adapted to cap the elongated member, means for disengaging said prolonging member from said operating rod, and means for constriction of said socklike member on said elongated member, insuring the gripping of the elongated member by axial displacement of the prolonging member with respect to the operating rod.

9. An arrangement according to claim 8, characterized in that said releasing means includes a ball selectively positioned in said operating rod for effecting the transfer of fluids to change the relative position of said piston and said sleeve.

10. An arrangement according to claim 6, characterized in that said sleeve has an upwardly tapered conical hollow member for guiding the sleeve over the top of the elongated member to be withdrawn.

11. An arrangement according to claim 6, characterized in that said disengaging means includes fluid means for forcibly sliding said sleeve with respect to said operating rod whereby positive gripping of the elongated member takes place.