US3747674A - Wash-over pipe spear apparatus - Google Patents

Abstract

A wash-over pipe spear apparatus for engaging and washing over a pipe stuck within a well bore and including a wash pipe, a retrieving assembly within the wash-over pipe having means for engaging the stuck pipe, releasable latch means joining the retrieving assembly and the wash-over pipe so that such assembly and pipe may be lowered into position, and a slip assembly. The retrieving assembly includes a releasable clutch which selectively controls setting of the slips and which may be operated by vertical manipulations of the supporting tubing string.

Description

United States Patent 1 Murray WASH-OVER PIPE SPEAR APPARATUS [75 Inventor: William Kirby Murray, Bossier, La.

[73] Assignee: Tri-State Oil Tool Industries, Inc., Bossier City, La.

[22] Filed: May 6, 1971 [2]] Appl. No.: 140,697

[52] US. Cl. 166/98, 294/8634 511 int. c1 E2lb 31/00 [58] Field of Search 166/98, 99, 138;

['56] References Cited I UNITED STATES PATENTS 2,762,438 9/1956 Naylor 294 8634 3,329,210 7/1967 Brown 166/138 3,070,170 12/1962 LeBus, Sr. et al.

LeBus,Sr. ..294/86.34

[ 1 3,747,674 1451 July 24, 1973 3,005,506 10/1961 LeBus, Sr. l66/99 Primary Examiner-James A. Leppink Att0rneyJ. Vincent Martin, Joe E, Edwards, M. H. Gay, Alfred H Evans and Jack R. Springgate [57] ABSTRACT A wash-over pipe spear apparatus for engaging and washing over a pipe stuck within a well bore and including a wash pipe, :1 retrieving assembly within the wash-over pipe having means for engaging the stuck pipe, releasable latch means joining the retrieving as sembly and the wash-over pipe so that such assembly and pipe may be lowered into position, and a slip assembly. The retrieving assembly includes a releasable clutch which selectively controls setting of the slips and which may be operated by vertical manipulations of the supporting tubing string.

4 Claims, 11 DrawingFigures PAIENIEDJUL 241915 SHEET 1 0F 4 m WW K M W/ V W m a SHEET 3 0F 4 W/'///'a/77 H Murray I N VEN TOR Armg/Z f:

PATENIEBJULZWB 3.747.674

SHEET h 0F 4 INVENTOR BY W 1 WASH-OVER PIPE SPEAR APPARATUS SUMMARY OF THE INVENTION This invention relates to new and useful improvements in wash-over pipe spear apparatus of the type used to wash over and drill around a section of pipe stuck in a well bore to effect its release and retrieval.

An object of this invention is to provide an improved apparatus wherein a retrieving assembly is combined with a wash pipe in such a manner that the wash pipe may be utilized to connect the retrieving assembly to a stuck pipe after which the wash pipe may be employed in the usual manner to wash over and drill around the stuck pipe to effect its release; said apparatus including means for anchoring the retrieving assembly in the wash pipe, which means is automatically actuated by the release and downward movement of said pipe, whereby the pipe may thereafter be retrieved with removal of the wash pipe from the well bore.

A further object is to provide an apparatus of the character described wherein the retrieving assembly includes an anchoring means which upon operation connects the assembly to the wash pipe together with a clutch means associated with and controlling said anchoring means to either permit or prevent the actuation of said anchoring means; said clutch means being operable by manipulation of the lowering pipe from which the wash pipe is suspended, whereby the anchoring means may be selectively rendered settable or nonsettable.

A particular object is to provide such an apparatus whereinthe clutch means associated with the anchoring means is operated by longitudinal or vertical movements of the lowering pipe or string from which the wash pipe is suspended and without thenecessity for any angular or rotative manipulation of said lowering pipe or string.

The apparatus of the present invention is an improvement over the wash-over spear apparatus disclosed in US. Pat. No. 2,762,438 issued Sept. 11, 1956 to C. A.

N aylor.

DESCRIPTION OF THE DRAWINGS AND THE PREFERRED EMBODIMENT These and other objects and advantages of the invention will become apparent from the drawings, the specification and claims. In the accompanying drawings which illustrate the preferred embodiment of the invention, and wherein like numerals indicate like parts:

FIG. 1 is a view in elevation and partly in section illustrating the wash-over pipe spear apparatus of this invention as it is lowered into the well bore;

FIG. 2 is a view in elevation of the apparatus of FIG. 1 after it has been connected to the stuck pipe in the well bore;

FIG. 3 is a view in elevation and partly in section taken along line 3--3 of FIG. 2 illustrating in detail a latch recess in the wash-overpipe;

FIG. 4 is a view in elevation illustrating the wash-over pipe spear with the parts in their operating positions;

FIG. 5 is a view in elevation of the subject apparatus after the stuck pipe has been freed and has fallen downward to effect setting of the anchor means;

FIG. 6 is a detailed view partly in section and partly in elevation taken along line 6-6 of FIG. 4, illustrating the slip clutch means; I l

FIGS. 7A and 7B-are enlarged detailed views in elevation and partly in section taken along line 7A7A and 78-73 of FIG. 5, and illustrating, respectively, the friction means and latch means of the retrieving assemy;

FIGS. 8, 9 and 10 are horizontal sectional views taken along lines 8-8, 9--9 and l0-l0 of FIGS. 7A and 7B.

In the drawings the numeral 10 designates generally the washover pipe and spear apparatus of the present invention. Such apparatus includes a tubular wash pipe 11, which is suspended from a lowering pipe or tubing string P so that it may be lowered into the well bore by means of said string. A retrieving assembly or spear, generally indicated at A, is adapted to be releasably mounted by latch means B within the bore of the wash pipe so that said assembly may be lowered therewith. The retrieving assembly or spear A also includes an an chor means generally indicated at C and located at the upper portion of the spear. The wash pipe 11 preferably has a washover shoe 12 secured to its lower end and the internal diameter of said pipe and bit are such that these parts may pass over and encircle a stuck pipe 13 which for some reason has become lodged within the well bore.

The retrieving assembly A is releasably connected by the latch means B within the tubular bore of the wash pipe 11 and is lowered with the wash pipe and bit until a threaded connecting pin 14 on the lower end of the retrieving assembly A engages the usual threaded box at the upper end of the stuck pipe orfish. As the connecting pin 14 engages the threaded box end of pipe 13, a rotation of the washover pipe connects said pin with the stuck pipe or fish. After such connection, the latch means B connecting the wash pipe and retrieving assembly are released or disconnected and the lowering string P, wash pipe and drill bit are rotated to drill out the obstruction around pipe 13 while flushing fluid is circulated downwardly through the wash pipe and around the stuck pipe. As will be described, when the obstruction is sufiiciently drilled out so that the pipe 13 is' released and falls downwardly, the anchor means C on the retrieving assembly are automatically actuated to anchor the retrieving assembly in the wash pipe whereby further downward movement of the released pipe 13 is arrested; thereafter raising of the lowering string P and the wash pipe lifts the retrieving assembly A and the previously stuck pipe 13 upwardly through the well bore so that it may be retrieved at the surface.

In FIG. 1, the wash-over pipe spear apparatus of the present invention is shown with the parts in position they assume during the lowering of the apparatus into the well bore. Retrieving assembly A is disposed within the bore of wash pipe 11 and is movable longitudinally with respect thereto. The retrieving assembly includes, from bottom to top, threaded pin. 14, safety joint 15 comprising lower and upper segments 15a and 15b, respectively, annular latching body 16, mandrel l7 and slip body 18. Threaded pin I4 is disposed from the lower end of the tubular lower safety joint segment 154. Upper safety joint segment 15b is disposed above the lower segment ,15a and has extension 15c of reduced diameter which telescopes into the bore of lower segment 15a. Rectangular lug 19 on extension of upper safety joint segment 15b engages and is slidable in a longitudinal slot 20a in the lower safety joint segment 15a. Shear pin 15d initially joins the lower safety when necessary, the remainder of the apparatus may be separated from outer safety joint segment a and pin 14 for removal from the well bore.

Upper safety joint segment 15b is threadedly connected at its upper end to latch means B comprising an annular latching body 16, having multiple latches 21 adapted to engage recesses 22 in the inner wall of wash pipe 11 (FIG. 3). Latching body 16, as shown in detail in FIG. 78, includes multiple longitudinal recesses 23 in which are disposed the individual latches 21. Four such recesses and latches are provided in the preferred form of the tool. Compression springs 24 fitted in circular sockets 25 in the back of latches 21 bear against the back of recess 23 and urge the latches radially outward. Maximum outward movement of latches 21 is controlled by stop lugs 26 on the upper and lower end of each latch which engage keepers 27 attached to latch body 16 by screws 28.

The particular construction of latch recesses 22 in wash pipe 1 l is shown in FIG. 3. The recesses are preferably formed integrally with wash pipe 11. The upper end of each recess is provided with a laterally extending shoulder 29 and an inclined or tapered surface 30 adjacent thereto which are adapted to be engaged by the upper edge 21a of latches 21 upon downward movement of wash pipe 11 relative to latching body 16. When the upper edges of latches 21 engage the laterally extending shoulders of recesses 22, the latches will act to prevent further downward movement of wash pipe 11 relative to latching body 16. However, when wash pipe 11 is rotated to the left or counterclockwise as viewed from the top of FIG. 1 so that latches 21 engage the inclined or tapered surfaces 30 of latch recesses 22, then the individual latches 21 ride up the tapered surface 30 and are forced radially inwardly against springs 24 so that wash pipe 11 may continue to move downwardly relative to latching body 16 and retrieval assembly A. Thus, the latch mechanism selectively permits or prevents relative longitudinal movement between the retrieval assembly A and wash pipe 1 1. Obviously, so long as latches 21 are engaging recesses 22, rotation of wash pipe 11 by the pipe string P will also rotate retrieval assembly A so that connecting pin 14 may be threaded into stuck pipe 13.

An added safety feature is preferably provided in the washover pipe spear by providing a counterbore 122 in washpipe 11 below recesses 22. Counterbore 122 has a lower horizontal shoulder 122a and an upper tapered shoulder l22b. The counterbore provides added safety while the tool is being run into the well. At this point only latches 21 in recesses 22 retain the spear within the washpipe. Should the'latches slip out of recesses 22, they will, upon downward movement of the spear assembly, enter counterbore 122, and the lower edges of the latches will engage horizontal shoulder 122a thus arresting further downward movement of the spear assembly. However, since the counterbore is tapered at its upper end, latches 21 can freely move out of counterbore 122 when the spear apparatus is engaged with the fish and the washpipe 11 is lowered to wash around the fish.

The mandrel 17 having a longitudinal bore 31 therethrough is threadedly connected to the upper end of latching body 16 and extends upwardly therefrom. It has formed on its upper end a slip expander or cone 32 which has an outer downwardly and inwardly inclined surface 33, the purpose of which will be hereinafter explained. Lower portion 17a of mandrel 17 is of reduced diameter and upper portion 17b is of enlarged diameter with downwardly facing annular shoulder 34 being formed between the two.

Anchor means C including an annular slip body 18 surrounds mandrel 17 below slip expander 32 and is longitudinally movable with respect to mandrel 17. A plurality of friction drag shoes 35 are mounted in longitudinal recesses 36 formed in the slip body 18 (FIG. 7A). Each friction shoe 35 has a plurality of sockets 37 in the rear wall thereof in which coil springs 38 are positioned. The inner portions of springs 38 contact the longitudinal inner wall 39 of longitudinal'recess 36 and are confined under compression to urge the friction shoes radially outwardly into contact with the inner surface of wash pipe 11. Each shoe 35 has upper and lower stop lugs 35a and 35b to limit outward movement. Upper stop lug 35a engages the back of keeper 40 on slip body 18 and lower stop lug 35b engages the inner wall of lower tubular extension 41 threadedly connected to the lower end of slip body 18.

The anchoring means C are provided for anchoring the retrieving assembly to the wash pipe and include slips or slip segments 42 (FIG. 7A) which are positioned near the upper end of slip body 18. Slips 42, which have downwardly extending teeth 43, are positioned on flexible supports 44 attached to slip body 18. Each of the segments 42 has a downwardly inwardly inclined inner surface 45 which is adapted to coact with the downwardly and inwardly tapered surface 33 on slip expander 32. Flexible slip supports 44 normally retain the slips in a nonengaged position; that is, with a space between the slip teeth 43 and the inner surface of wash pipe 11. However, when the slip expander 32 moves downwardly to contact tapered surfaces 45, the slips will be expanded outwardly to engage the inner wall of wash pipe 11 to anchor the retrieving assembly A within the wash pipe.

Whether slips 42 of the retrieving assembly are in a settable or nonsettable position is determined by clutch means 46 (FIG. 7A) disposed at the lower end of slip body 18 within the bore of lower tubular extension 41. The clutch means comprise multiple, preferably three, arcuate segments 47 which are retained within tubular extension 41 by their lower ends engaging upwardly facing annular shoulder 48 near the lower end of tubular extension 41 and by their upper ends engaging the lower edge 49 of slip body 18. The segments 47 are adapted for limited radial movement and are urged radially inwardly by the compressive force of circular springs 50 fitted in grooves 51 in the outer surface of segments 47. The longitudinal inner surface of each segment comprises three surfaces: An upper surface 47a of smaller internal diameter and having an annular recess 52 therein, a lower surface 47c of greater internal diameter, and a downwardly and outwardly tapering surface 47b which joins the other two.

To prevent the setting of slips 42, arcuate clutch segments 47 coact with annular shoulder 34 which forms the boundary between reduced diameter portion 17a and enlarged diameter portion 17c of mandrel 17. When segments 47 are at their radially inwardmost position engaging the outer surface of reduced diameter portion 17a of mandrel 17, annular shoulder 34 on mandrel 17 will engage upper edges 47a of segments 47 so that mandrel 17 .cannot move further in a down- Clutch release means for moving the clutch segments 47 into a retracted position permitting downward movement of mandrel l7 and slip expander 32 are provided by clutch release ring 53 (FIG. 6) which is slidably disposed about reduced diameter portion 17a of mandrel 17. Clutch release ring 53 has at its upper end downwardly and outwardly tapering cam surface 54 which is designed to coact with tapering surfaces 47b on clutch segments 47 and also has near its upper end an annular bead 55 which is adapted to fit within annular recesses 52 on the inner surfaces 47a of clutch segments 47. As shown in FIG. 6, when clutch release ring 53 is positioned within the split ringformed by clutch segments 47, then coacting tapered surfaces 54 on the ring and 47b on the segments urge the segments radially outwardly against circular springs 50 until annular bead 55 on ring 53 engages annular recess 51 on segments 47. Withthe parts thus positioned, the clutch means are released and the slips will automatically set upon relative downward movement of mandrel 17, as will be hereinafter described.

In the operation or use of the wash-over pipe spear apparatus of this invention, the apparatus is lowered into the well bore with the parts in the position shown in FIG. 1. Latches 21 are disposed within latch recesses 22 so that retrieving apparatus A is supported thereby. During the lowering operation, clutch release ring 53 is engaging clutch segments 47 so that slips 42 and slip expander 32 are in a settable position so that in the event latches 21 become disengaged from recesses 22 and fail to engage counterbore 122, the slips will set and still prevent the loss of the spear assembly. Telescoping safety joint is in a fully telescoped position and held in place by shear pin 15d.

The apparatus is lowered until washover shoe l2 and the lower portion of wash pipe 11 pass over and round stuck pipe 113 and the threaded connecting pin 14 contacts the upper portion of pipe 13. When such engagement occurs, wash pipe 11 is rotated to the right or clockwise (as viewed from the top of FIG. 1) by rotating lowering string P which supports wash pipe 11 from the surface of the well. Rotation of the wash pipe 11 is imparted to the threaded connecting pin 14 by reason of engagement of latches 21 within recesses 22 of wash pipe 11. The right-hand rotation of wash pipe 11 positions latches 21 under lateral shoulders of latch recesses 22 so that disconnection of the latches from the recesses is prevented even if slight relative longitudinal movement tends to occur between the wash pipe 11 and the retrieving assembly A.

After connecting pin 14 is threaded into pipe 13, an upward pull is taken on the lowering string P to sever shear pin 15d so that inner and outer safety joint sections 15a and lSb may telescope relative to each other and the rectangular lug 19 may move upwardly in slot 20a. The parts are shown in this configuration in FIG. 2 with the safety joint fully extended and lug 19 at the upper extremity of slot 20a.

Next, the wash pipe 11 is lowered until upper safety joint section 15b is fully telescoped into lower safety joint section 150. The wash pipe 11 is rotated to the left, or counterclockwise, to move latches 21 into a position below inclined surfaces 30 of latch recesses 22. Then the wash pipe 1 1 is slacked off or lowered further. Since the retrieving assembly is connected to the stuck pipe 13, it will remain stationary and wash pipe 11 will .move relatively downwardly as latches 21 are freed from recesses 22. The parts are shown in this position in FIG. 4. The tool is now in position to begin drilling out the obstruction surrounding pipe 13. The wash pipe 11 is rotated to rotate the drill bit 12 to effect the drilling out of the blocking debris and washing fluid is circulated down through the lowering string P, wash pipe 11 and around the retrieving assembly A to the drill bit 12. 1

When the stuck pipe becomes sufficiently loose, it will generally tend to fall downwardly within the well bore. It is desirable to limit this downward fall to avoid damage to the tool and damage to the pipe section 13 which usually includes expensive drill collars. This is accomplished by automatic setting of slips 42. As the pipe 13 falls downwardly, lower safety joint section 15a will move downwardly relative to upper safety joint section 15b and pin 19 will move relatively upwardly in slot 200 until it reaches the upper end of slot 20a. Thereafter, further downward movement of the pipe causes upper safety joint 15b, latch body 16 and man drel 17 to move downwardly relative to the wash pipe 11 and slip body 18. Slip body 18 will initially remain stationary relative to wash pipe 11 by virtue of friction shoes 35 engaging the inner surface of wash pipe 11. As best seen in FIG. 6, continued downward movement of mandrel 17 causes shoulder 34 on mandrel 17 to engage the upper edge of clutch release ring 53. As this happens, clutch release ring 53 begins moving downwardly with the mandrel and annular bead 55 will un' seat from annular recess 52, forcing clutch segments 47 radially outwardly a sufficient distance to clear shoulder 34. Continued downward movement of mandrel 17 will cause tapered surface 33 on slip expander 32 to engage tapered surfaces 45 on slips 42 and urge the slips 42 outwardly until they engage the inner wall of wash pipe 11. This will arrest further downward movement of the retrieving assembly A and of pipe 13 which will then in effect be supported by wash pipe 11 and may then be removed from the well bore by raising the tubing string supporting wash pipe 11.

In the event pipe 13 does not :fall downwardly as would occur if the pipe were resting on the bottom of the well bore, or if not enough debris has been drilled away, the slips may still be set by raising the lowering string P and thus wash pipe 11. As slip body 18 rises with the wash pipe 11, it creates the same relative movement between the slip body and mandrel 17 as previously described and effects the setting of slips 42 so that an upward pull on pipe 13 may be taken with the pipe string supporting wash pipe 11.

ln the process of washing over the fish 13, pipe is added to the top of drill string P one joint at a time.

This requires that the wash pipe be picked up approximately 30 feet to allow a joint of drill pipe to be installed in the drilling string. As previously described, the slips C are set either by the fish falling or by raising the wash pipe. Therefore, the drill string P is first raised to set the slips and a strain is taken to assure that the fish is still stuck. Next, the pipe is lowered to close the telescoping joint plus enough to permit the clutch segments 47 to be below shoulder 34. (FIG. 6). The wash pipe may then be picked up without setting the slips and an additional joint of pipe added to the drill string P.

If washover shoe 12 on the wash pipe 11 should become 'dulled before the stuck pipe 13 is fully drilled out, and the taking of an upward pull as described above fails to free the pipe, then it will be necessary to bring wash pipe 1 1 and retrieving assembly A out of the well bore to replace drill bit 12 with a new bit so that drilling may continue. However, the wash pipe 11 may not simply be withdrawn since the anchor means C are engaged," anchoring retrieving'assembly A within wash pipe 11 and threaded pin 14 on retrieving assembly A is engaged with the stuck pin 13, and the wash pipe may not be lowered to release the anchor means as described above, since the washover shoe 12 is already on the bottom. When this occurs, the safety joint 15 described above is utilized to free the wash pipe 11 and retrieving assembly A as follows: An upward pull just having been taken, the parts will be in the position shown in FIG. with pin 19in the upper end of longitudinal slot 20a. The supporting string P is then slacked off slowly while a left-hand torque is maintained. As wash pipe 11 moves downwardly, the pin 19 will move downwardly in slot 20a until opposite the opening to J-slot 20b. Then the left-hand torque will cause pin 19 to move into the horizontal portion of J-slot 20b and into position below the vent port of J-slot 20b. An upward pull on wash pipe 11 will cause pin 19 to move upward in slot 20b. Since slot 20b is open at the top, the wash pipe 11 and retrieving assembly A may then be raised to the surface of the well bore, leaving lower section a of safety joint 15 and connecting pin attached to the stuck pipe 13. After washover shoe 12 is replaced, the tool may be run back into the well and reconnected to section 15a of safety joint 15 and drilling continued.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and

various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made'within the scope of the appended claims without departing from the spirit of the invention.

1 claim: I l. A wash-over pipe spear comprising,

an outer tubular member adapted to be supported from a pipe string within the well bore; and a retreiving assembly disposed within the bore of said outer tubular member including, a mandrel having thereon slip-actuating means and clutch release means,

connection means on said mandrel for attaching said retreiving assembly to a stuck object within the well bore,

anchor means for selectively anchoring said retrieving assembly within the bore of said outer tubular member,

said anchor means including a slip body disposed about said mandrel and having slips adapted to coact with said slip-actuating means to set said slips, and

clutch means for selectively rendering said anchor means settable or nonsettable,

said clutch means including multiple clutch segments carried by said slip body and resilient means normally urging said segments radially inwardly,

said clutch segments being adapted to coact with said mandrel to render said slips nonsettable and to coact with said clutch release means to render said slips settable,

said clutch means being operable solely by vertical manipulations of said outer tubular member.

2. A wash-over pipe spear apparatus adapted to be lowered into a well bore comprising a wash pipe adapted to be suspended in the bore from a pipe string; and

a retrieving assembly slidably disposed in said wash pipe including,

a mandrel extending longitudinally within said wash connection means on the mandrel for connecting the retrieving assembly with the stuck pipe,

releasable latch means on said mandrel for selectively latching said retrieving assembly to said wash pipe whereby said wash pipe maybe manipulated to connect the connection means on said mandrel to said stuck pipe,

a slip expander secured to said mandrel,

a slip body mounted on said mandrel below said slip expander and having slips adapted to move into anchoring engagement with said wash pipe upon downward movement of said expander relative thereto,

said slip expander being movable downwardly relative to said slips to move said slips into anchoring engagement with said wash pipe when said stuck pipe becomes loosened and falls downwardly,

said slip body and anchoring slips being longitudinally movable relative to said mandrel,

friction means on said slip body engageable with said wash pipe for maintaining said slip body and slips in a position spaced below said slip expander until said slip expander moves relatively downwardly within said wash pipe,

multiple clutch segments carried by said slip body and adapted to coact with said mandrel to normally prevent downward movement of said slip expander relative to said slip body,

clutch release means on said mandrel adapted to engage said clutch segments and move said clutch segments into a position permitting downward movement of said slip expander relative to saidslip body to allow setting of said slips upon predetermined relative movement of said wash pipe with respect to said slip expander,

said clutch release means being'movable between po sitions engaging and out of engagement with said clutch segments solely by vertical movement of said wash pipe. v

3. The apparatus according to claim 1 wherein said multiple clutch segments are relatively elongate and 10 temal annular bead adapted to coact with said circular groove in said clutch segments to retain said clutch release means in a position with respect to said clutch segments which renders said slips settable.

Claims (4)

1. A wash-over pipe spear comprising, an outer tubular member adapted to be supported from a pipe string within the well bore; and a retreiving assembly disposed within the bore of said outer tubular member including, a mandrel having thereon slip-actuating means and clutch release means, connection means on said mandrel for attaching said retreiving assembly to a stuck object within the well bore, anchor means for selectively anchoring said retrieving assembly within the bore of said outer tubular member, said anchor means including a slip body disposed about said mandrel and having slips adapted to coact with said slipactuating means to set said slips, and clutch means for selectively rendering said anchor means settable or nonsettable, said clutch means including multiple clutch segments carried by said slip body and resilient means normally urging said segments radially inwardly, said clutch segments being adapted to coact with said mandrel to render said slips nonsettable and to coact with said clutch release means to render said slips settable, said clutch means being operable solely by vertical manipulations of said outer tubular member.

2. A wash-over pipe spear apparatus adapted to be lowered into a well bore comprising a wash pipe adapted to be suspended in the bore from a pipe string; and a retrieving assembly slidably disposed in said wash pipe including, a mandrel extending longitudinally within said wash pipe, connection means on the mandrel for connecting the retrieving assembly with the stuck pipe, releasable latch means on said mandrel for selectively latching said retrieving assembly to said wash pipe whereby said wash pipe may be manipulated to connect the connection means on said mandrel to said stuck pipe, a slip expander secured to said mandrel, a slip body mounted on said mandrel below said slip expander and having slips adapted to move into anchoring engagement with said wash pipe upon downward movement of said expander relative thereto, said slip expander being movable downwardly relative to said slips to move said slips into anchoring engagement with said wash pipe when said stuck pipe becomes loosened and falls downwardly, said slip body and anchoring slips being longitudinally movable relative to said mandrel, friction means on said slip body engageable with said wash pipe for maintaining said slip body and slips in a position spaced below said slip expander until said slip expander moves relatively downwardly within said wash pipe, multiple clutch segments carried by said slip body and adapted to coact wiTh said mandrel to normally prevent downward movement of said slip expander relative to said slip body, clutch release means on said mandrel adapted to engage said clutch segments and move said clutch segments into a position permitting downward movement of said slip expander relative to said slip body to allow setting of said slips upon predetermined relative movement of said wash pipe with respect to said slip expander, said clutch release means being movable between positions engaging and out of engagement with said clutch segments solely by vertical movement of said wash pipe.

3. The apparatus according to claim 1 wherein said multiple clutch segments are relatively elongate and are adapted to move radially with respect to said mandrel to render said slips selectively settable and nonsettable.

4. The apparatus of claim 1 wherein said clutch segments include a circumferentially extending groove and wherein said clutch release means includes an external annular bead adapted to coact with said circular groove in said clutch segments to retain said clutch release means in a position with respect to said clutch segments which renders said slips settable.

Images