US3227214A

US3227214A - Method and apparatus for removing a pipe from the well

Info

Publication number: US3227214A
Application number: US57873A
Authority: US
Inventors: Rural W Whann
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-09-20
Filing date: 1960-09-20
Publication date: 1966-01-04
Anticipated expiration: 1983-01-04

Description

Jan. 4, 1966 R; w. WQ-IANN METHOD AND APPARATUS FOR REMbVING A PIPE FROM THE WELL Filed Sept. 20, 1960 2 Sheets-Sheet 1 INVENTOR. Rural M nmfl Jan. 4, 1966 R, W WHANN 3,227,214

METHOD AND APPARATUS FOR REMOYING A PIPE FROM THE WELL Filed Sept. 20, 1966 2 Sheets-Sheet z 7 M2 94 /06 M0 I i 1 m8 9/ 4 94 1 ii-i INVENTOR. 9 90 Rural M Wfiflflfl Z I" 84 I 4/ United States Patent 3,227,214 METHOD AND APPARATUS FOR REMOVING r l A PIPE FROM THE WELL Rural W. Whann, 315 W. 9th St., Los Angeles, Calif. Filed Sept. 20, 1950, Ser. No. 57,873 11 Claims. (Cl. 166-35) This invention relates to a tool for use in separating a string of pipe in a well above the point at which the pipe is stuck. This application is. a continuation-in-part of my copending application entitled Method and Apparatus for Removing a Pipe From the Well, Serial Number 363,334, filed June 22, 1953, now abandoned.

When a string of pipe becomes stuck in a well and it becomes necessary to remove at least a portion of the pipe, an operator must determine the location of the highest point at which. the pipe is stuck if he is to remove as much of the pipe asipossible. When an operator employs a tool of well-known type for locating the point at which a pipe is stuck in a well, he thereafter removes the locating tool from the well and employs another tool for separating the pipe above its. stuck point. consumed by these operations of withdrawing the locating tool from the well and positioning a pipe separating tool down in the well, the pipe may. become stuck or frozen at a point above that which has been located, whereupon the operator will have to determine the, location of the new stuck point. Thus, he not only loses benefit of the time and efiort he has already spent, but also he may not be able to salvage or reclaim that portion of the string of pipe lying below the highest stuck point. This chance that the pipe may become stuck or frozen at a higher point is especially great dun'ng drilling operation, for, when drilling has been stopped for any reason, the drilling mud used in the drilling operations may gel or thicken around the stationary drill stem, or a freshly penetrated earth formation may be caused to cave in on the drill stem. It is important therefore, that no time be lost in separating a drill stem above its stuck point and removing it from the well. It is important, too, that the pipe separating tool .be positioned adjacent to a point in the pipe which -is known to be free, i.e. above the highest stuck point, when the pipe is being separated, in order to insure that the portion of the pipe above the place of separation thereof may be pulled from the well and not be found to be stuck at a higher point after it has been separated. As used herein the word pipe refers to a drill stem, a string of casing, a tubing or any other string of pipe employed in a well. i

The present invention makes itpossible' to separate a pipe in a well at a point thereof which is known to be free at the time of separation, and it is an object of this invention to provide a tool that not only locates the highest stuck point and permits an operator to separate the pipe immediatelyabove that point in but a single, trip of the tool into the Well, but also transmits a signal or indication to the top of the well that the tool is positioned adjacent to a free point in the pipe when the pipe is being separated with use of the tool. i It is a further object of the present invention to provide a well tool that may be positionedat a free point in the pipe immediately above its highest stuck point in a simple and quick operation.

A still further object of the invention is to provide a well tool that operates quickly nd efiectively n ep rat ing a stuck pipe at a known free point therepf,

Another objec of he invent on s to p ov d pipe separating means that is simple in construction and adapted for use in combination with most any of the types of stuck point locating tools that are used in well operations.

There are several known methods for separating a pipe In the time at a point down in a well. A pipe may be severed as, for example, by being shot off or cut OE With the use of a jet cut off tool, or the pipe may be backed off by twisting it in a direction that will unscrew a threaded joint thereof which connects two sections of the pipe. In the backing oif method of separating a pipe, it is necessary first to jar or otherwise loosen a threaded connection of the pipe, before the pipe can be unscrewed at that connection. When the pipe connections are formed of collars around adjacent ends of the pipe sections, an operator may jar the collar at the connection to be separated, and in some cases expand the collar, in order to loosen it. In one form of the present invention I provide a well tool having means for finding a pipe connection in the free portion of a pipe above the highest point at which the pipe is stuck in a well, such pipe connection finding means being positioned on the tool within the limits of means for jarring the located connection, whereby, upon signal that the position of the desired pipe connect-ion has been located, the said jarring means will be positioned directly opposite to such pipe connection and the connection may be loosened without further adjustment of the tool in the well.

It is another object of this invention to provide a stuck point locating tool that operates in response to torque applied to the top of the pipe, and having connection jarring means, whereby the impact of the jarring force loosens a known free pipe connection while torque is being applied in a direction tending to unscrew the connection, thus causing the pipe to spin loose when the jarring force is released. i

It is another object of the invention to provide a stuck point locating tool which carries an explosive separating charge at a position on the tool corresponding tothe position at which it is desired to separate the pipe when the stuck point is found.

Another object of the invention is to provide a method involving determining the lowest free point of a pipe in a well or bore hole and simultaneously positioning an explosive charge adjacent the free point whereby the sepa ration of the pipe can be effected by means of the same tool or instrumentality without further movement thereof after the free point has been found.

It is still another object of the invention to provide a locating tool to locate the first free pipe collar above the stuck point and carry a jarring charge to this point whereby the charge is separated from the locating tool and 'fixed inthe threaded collar joint so that the locating tool may be moved to a. safe distance above the explosive charge thereby saving the locating tool.

Another object of the invention is to provide for a continuous and progressive operation in which time is reduced and the economy of the Op ration is raised.

Further objects and advantages of the invention will become apparent from the following detailed description taken in connection with the drawings, which are for illustrative purposes only, wherein:

FIG. 1 is a schematic sectional view showing a pipe which is stuck in a Well, with an embodiment of the nvention positioned therein and shown in elevation with a portion thereof shown in vertical section;

FIG. 2 is a vertical section of the lower portion of an alternative form of the invention;

FIG. 3 is a vertical section of a pgrtion of angther a e n t form 9f t e nv nt n;

FIQ. 4 is another alternative form of the inventign showing a side elevation with a portion broken away which the spring fingers arp in a lgcked inoperative pgsition;

FIG. 5 is a similar view to FIG. 4 but the spring fingers are shown in a released position;

FIG. 6 is a vertical section of the arrangement shown in FIG. and

FIG. 7 is a sectional view taken on line 7-7 of FIG. 6.

Throughout the drawings, like reference numerals represent like parts throughout the several illustrated embodiments.

For purposes of simplifying the description hereof, I have chosen to describe the present invention by reference to the torsion sensing tool illustrated and described in U.S. Letters Patent No. 2,550,964, granted on May 1, 1951 to Norman Brookes. Referring to FIG. 1 of the drawing hereof, the numeral 10 designates a string of pipe which is stuck in a well 11 at 12. The well tool 15 which I have shown positioned in the pipe 10 is similar in certain parts thereof to the tool shown in the said Patent No. 2,550,964, and which operates in response to torque applied to the top of the pipe at ground level. The tool 15 comprises a pair of pipe engaging members or

bow spring cages

16 and 17, spaced apart by the bar 18. The upper cage 16 is rotatably mounted on the bar 18 while the lower cage 17 is fixed to the bar.

The tool 15 is lowered into the pipe 10 by means of the cable 19 which is secured into the cable socket 20 mounted on and rotatable with the top end of upper cage 16. The cable socket 20 contains certain electrical elements that are arranged in a known way so as to be actuated in response to relative rotation of the cage 16 and the bar 18. Such electrical elements are connected through conductors inside the cable 19 to electro-responsive indication means at the top of the well, whereby any electrical impulses caused by such electrical elements as a result of relative rotation of cage 16 and bar 18, will be indicated to the operator at the top of the well. The details of construction and mode of operation of such electrical elements, electro-responsive indication means and the circuit therefor, do not constitute the essence of the present invention, and it is considered suflicient for the purposes of this description to refer to such elements and means, generally, as those not familiar with the details thereof may refer to the said Patent No. 2,550,964, for a full and complete description.

In the embodiment shown in FIG. 1, a pipe severing means, designated generally by the numeral 25, is mounted on the bar 18 at a location between the

cages

16 and 17. The pipe severing means which is illustrated comprises a shaped charge of explosive material 26 having sufficient explosive capacity to eut'the pipe 10 off at that portion thereof which surrounds the shaped charge. The shaped charge of explosive material 26 is supported between two

discs

27 and 28, threaded on opposite ends of a sleeve 29 secured to the bar 18 as with the screws 30. A covering 31, of paper or other suitable substance, protects the explosive material from being damaged. A detonation or blasting cap 32 is fitted into a well in the shaped charge through a slot 33 in the disc 27 and is electrically connected to the conductors 34 which in turn are connected to a suitable blasting box 35 at the top of the well. The wires or conductors 34 may be attached .to the bar 18 as with clips 36 or other suitable tying means, and, as is obvious, they may, if desired, be contained within the cable 19.

v In operation, the tool is lowered into the pipe 10 and torque is applied to twist the pipe, whereby only the free portion thereof, i.e., that portion above the highest stuck point 12, will be turned while that portion of the pipe below the stuck point will not turn. Upon applying torque to the pipe relative rotation occurs between adjacent annular portions of the pipe throughout its full length above the stuck point. If at the time of applying such torque, the stuck point locating and pipe several tool is positioned above the stuck point 12, the angle of rotation of the upper cage 16 will be greater than that of the cage 17 and bar 18. This occurrence of relative rotation between the elements of the tool will be transmitted by the electrical elements and electro-responsive indication means to the top of the well, and the operator will know that his tool is positioned above the highest pointat which the pipe is stuck. The operator will then further lower the tool and again twist the pipe, repeating these steps until a position is reached where no rotation of the tool occurs. When no relative rotation between the cages of the tool has occurred upon twisting of the pipe, the electro-responsivc indication means at the top of the well will be still and the operator thus knows that his tool is located below the stuck point. He thereupon raises the tool to a location where relative rotation occurs and preferably while torque is still applied to the pipe, he operates the blasting box causing the shaped charge 26 to explode and sever the pipe at the annular portion surrounding the explosive, which portion is known to be free at the time of the explosion. Instead of locating the stuck point by making tests at successively lower points in the free portion of the pipe, the operator may lower the tool to the bottom of the well and make his tests at successively higher points until he reaches a position where relative rotation occurs between the elements of his tool, whereupon he may cut the pipe off at that position in the manner described above. By maintaining a twist on the pipe and operating the pipe separating means only upon indication of relative rotation between the pipe engaging members, the operator will know that the pipe is being cut off at a point above its highest stuck point, and he may proceed to raise the pipe immediately without fear that it has become stuck above the place of cut off.

In the modification shown in FIG. 2, I provide a means for jarring a pipe connection in the free portion of the pipe, and means for finding such connection, the connection finding means being arranged within the limits of the jarring means on the well tool, whereby upon location of a pipe connection above the point at which the pipe is stuck, the jarring means will be positioned opposite to such pipe connection without further adjustment of the tool. The connection jarring means in the illustrated embodiment includes the rod 40 which is suspended by the cup 41 from the lower end of the bar member 18 below the pipe engaging member 17. The cup 41 is fastened to the end of the bar member 18 in any suitable manner, as by the screws 42. Wound around the rod 40 and extending the full length thereof is a string 43 of explosive material, such as, for example, primacord. One end of the explosive cord 43 extends into the cup 41 and is knotted around a detonation or blasting cap 44 wired to a blasting box at the top of the well.

The connection finding means of the embodiment shown in FIG. 2 comprises a tubular member 45 having a plurality of springs 46 circumferentially secured thereto. The rod 40 passes through the tubular member 45 and thereby supports the connection finding means. Axial movement of the tubular member 45 with respect to the rod 40 is prevented by means of the screws 47. The springs 46 extend outwardly and upwardly from the tubular member 45 and are formed so as to normally extend outwardly beyond the circumference of the well pipe. In FIG. 2, the string of pipe 10 is shown as comprising an upper section 50 and a lower section 51, the adjacent ends of the sections being connected by means of a threaded collar 53. In practice, the pipe sections do not abut each other, thus leaving a space 54 between the ends of the pipe sections. The springs 46 are shown in the drawing as being engaged with the shoulder 55 provided by the end of pipe section 50 in the space 54 between the pipe sections.

In operation the tool shown in FIG. 2 is lowered into the well and as explained above for operating the tool shown in FIG. 1, the pipe is tested at successively lower points until the stuck point is located. The tool is then raised to a position indicating relative rotation between the bow spring cages. With torque applied to the pipe ina directiontending to unscrew the'connection 53, the tool is again raised until the springs 46 snap into the space 5410f the pipe connection and engage the shoulder 55. This action of the springs 46 offers strong resistance to fu'rther'upwa'rd movement of the tool in the well there by signalling the operator that a pipeconnection has-been located in the free portion of the pipe. Thus, theexplosive c ord43 becomespositioned centrally of the pipe connection and upon detonation thereof, it imparts a severe asserts the "pipe coiinection and with the twist that is beiri'gapplid at'the top at the well, causes the vpipe to spin loose at that connect-ion. i I

Iii-FIG. 3, the connection finding means and thestring or explosive materialare shown as beingpositioned between

thetwopipeengagingrnembers

16 and 17. The sleeve member 58, which corresponds in function anddesign-to the thbular member 45. shown in FIG. 2, is"secured to the bar 18 in any suitable manner as with'the screws '59. The string or cord of .explosive material 60 is woundlaround the bar 18 and the sleeve membenSS iandiss-ecured tothe bar 18 in any 'suitablefas-hion as with'the clip -61. As in FIG. 2, the explosive cord is provided at its upper end with a detonation or blasting cap i63,electrically connected-to"ablasting boxat the top of the well. The arrangement shown in FIG. Spositions the explosive string centrally of the freepi-pe'collar to be 'fj arre dup-on location of such collar above the ainter which the pi-peisstuc k. Theexpl osive stringextends beyondthe limits of the oollarifinding means andis preferably actuated while'the collar is'being strained by 'a fo rcet endingto unsciew it from the top of theweil. It 'seenisobvious, thereforej-that the use of a tool of the type hereinerbri ve described will iiisu re the operator thereof that the pipe connection jarring means is positioned opposite toapipe collar whichis kn'own to be free and i above the highest stuck poihtof the pipe when the jarriag' 'ean is actuated.

If desired, the eX-plcsivechar'ge for cuttin'g olfthe well pipemay be positioned en la trod secured to the lower end otf'the ibar -18,"'in a maniiero'orresponding to that illhsti'atedinFIG;2. Also, itis obvious that the shaped charge 26 may be constituted of less explosive material than required for severing a pipe,whereby it acts to hi'e relyjar a threaded pipe connection. In the case where the' collar jarrihg means comprises a shaped charge, as

distinguished from a string or cord of explosive material, thepipec onnection engaging ends-of the connection finding isp'rings are arranged to'engage a pipe connection within the vertical lirnits ofthe shaped change, whereby, upon location of a free pipe connection, the jarring means will be positioned di'rect'lyoppositeto such pipe connection "without further adjustment of thetool in the Well. It is obvious, r00, thata pipe severing means or a connection jarring means, as herein" described, may be pos-iti-oned,- if desired, on the cable19 above the stuck point locating frriearis of the tool.

From the foregoing it will be observed that in the form ofthe invention of FIG. 1,"when the stuck point has been fniu'nd, the'exp-l-osive-c harge will at that time be vpositioned just above 'it in proper position "for separating the casing.

"No further movemeneor the tool is required, and accordingly; substantial economies "in time and manipulation "of "equipment-areachieved. In theforms of the invention shown in FlGS. 2 and3, after the stuck point has been found,"ther'e isonly one further movement of the tool,

. 18 respectively. At the lower end of the tubul ar'meimher explosion area of the jarring charge.

72 there is welded or secured in like manner a cup-like receptacle having a bottom 82 and anannularwall 34 projecting upwardly from the circumferentialedge {of the bottom wa-ll 82. The tubular member 72 is centrally 1ocated on the bottom wall82 so as to form an annular cavity 86 between the inner side of the wall 84 and the lower end 88 of thetubula'r member 72. The annular cavity 8 5 receivesthe explosive jarring charge 90. A detonation orblast-ing cap 91 is fixed within t-he' jar-ring charge 90 through an opening 101 in the locking plate 96 whereby the plate 96 actsin conjunction with-the cup 80 as a support means for the explosive charge 90.

Electrical conductors 93 leading from the cap 91 are wrapped sufficiently around the tubular sleeve 72 so that the well tool may be separated from the charge 90 and moved upwardlyin the pipe at a safe distance from the explosion.

There are a plurality of equally spaced .s-pring fingers 92 circumferentially secured to the side wall 84. At the uppercnds of the springs 92 there are lip portions 94 which, when in al ocked position as shown inFIG. 4, are securedto the lockingplate 96. The locking plate'96 has equally spaced peripheral projections withslots or openings 192 toreceive the lip 94 of the spring finger 92. Also shown in FIG. 6 is an actuating means 104 centrallylocated in the tubular sleeves 72 and shown as a solenoid having an armature 166 secured to the locking plate 96 so asto longitudinally move theplate 96 out of engagement with the spring fingers 92 causing the fingers to spread and extend into the space 54 between the ends of the

pipe sections

52 and 51 respectively. In order for the'plate '96 to slidably move on the sleeve 72, there have been formed vertical slots 103 in the lower end 88 of the'sleevemernber 72 to accommodate matching webs which are in the locking plate 96. The solenoid 104 is electrically connected by the conductors 111 which in turn are connected to conductors'112 centrally mounted withinthe well "tool bar 18 passingthroug-h the tool 15 and inside the cable 19 to the top of the well whereby shearpin 74. The combination of the tool is then lowered into the well pipe 10 and the sensing device then locates the first free collar joint above the stuck point in the well. The tool is then gradually lifted in anupward direction and in so doing,'the solenoid is energized releasing the spring fingers 92 so they may engage in the space 54 'between the upper pipe 52and the lower pipe 51'.

Thefingers "92will then engage the lower edge 'of the upper pipe 52, the spring fingers being of such atension as to hold the jarring charge in place and force the shearing pin to shear at the lower end of the Well tool and thereby leaving the connecting finding means located 'in a central position at the collar connection, that is, at the plane of the space 54 between the adjacent ends of the pipes at the selected joint. The well tool continues in an upwand direction unwinding the conductor'93 of the detonationcap "91 to a suflicient length to clear the well tool from the Although I have shown a solenoid for releasing the locking plate 96, it can be well understood that the releasingmeans may be also a mechanical means. Likewise, it can be understood that the detonation 'capmay also be set off either by a mechanical means or by having the separated Well tool taken from the Well and thereafter dropping a weight or a go devil to set off the detonation.

Although the present invention has been illustrated and described with particular reference to a tool having .bow

*spring' cages for engaging the'inner Wall of the .pipeyand operating in response to torsional strain applied to the pipe, the pipe separating means of the present invention may be used in combination with other means for locating a point at which a pipe is stuck in a well. An example of such other stuck point locating means is illustrated and described in US. Patent No. 2,530,309, granted on November 14, 1950, to Philip W. Martin. Also, I desire to have it understood that other connection finding means may be used instead of the springs 46, such as, for example, any magnetic collar finder, the design and mode of operation of which are known to those skilled in the art of well tools; the essence of the present invention being the provision of a free point locating tool having means for causing a pipe to be separated at a place therein which is known to be free and above the highest point at which the pipe is stuck, when separation is effected.

I claim:

1. A method for separating a stuck pipe above a stuck point so as to salvage the free pipe, all in such continuous and rapid progression as to produce a substantially continuous unity of operation which comprises the steps of: inserting a combination stuck point measuring tool and explosive device; locating the stuck point of the pipe; determining the position of the first free collar joint above the stuck point; positioning an explosive jarring charge at the said joint, whereby the said charge may be released to engage said collar joint; holding said positioned charge in place with respect to the pipe; separating the measuring tool from said positioned charge and moving said tool to a safe area above the charge; and discharging said explosive.

2. A method for separating well casings above a stuck point so as to salvage the freed well casing, all in such continuous and rapid progression as to produce a substantially continuous unity of operation which comprises the steps of: inserting a combination stuck point locating and explosive device; locating the stuck point of the pipe; locating said explosive device at a desired free point relative to said stuck point; engaging the explosive device with the pipe at said desired point; separating the locating device from the explosive device; moving said locating device to a safe area in the casing; and discharging the explosive of said explosive device.

3. Apparatus for locating the stuck point of pipe in a well, locating explosive at a joint adjacent thereto, and igniting same to free the joint, the combination including: stuck point locator means adapted to be lowered into a well, including means whereby the stuck point of a pipe may be located, and including means at the surface of the well indicating where such stuck point is located; explosive means carried by the apparatus lowered into the well; means whereby said explosive means may be positioned adjacent to a joint in said pipe; there being means, whereby said explosive means is held in position; means permitting said explosive means to be separated from the remainder of the apparatus lowered into the well; and means at the surface of the ground whereby said explosive may be ignited.

4. Apparatus for locating the stuck point of a pipe in a well, locating exposive at a joint adjacent thereto, and igniting same to free the joint, the combination including: stuck point locator means adapted to be lowered into a well, including means whereby the stuck point of a pipe may be located, and including means at the surface of the well indicating where such stuck point is located; explosive means carried by the apparatus lowered into the well; means whereby said explosive means may be positioned adjacent to a joint in said pipe; means on said explosive means to engage said pipe; means permitting said explosive means to be separated from the remainder of the apparatus lowered into the well; and means at the surface of the well operable to fire said explosive means while the apparatus is still in the well.

5. Apparatus for locating the stuck point of pipe in a well, locating explosive at a joint adjacent thereto, and

8. igniting same to free the joint, the combination including: stuck point locator means adapted to be lowered into a well, including means whereby the stuck point of a pipe may be located, and including means at the surface of the well indicating where such stuck point is located; explosive means carried by the apparaus lowered into the well; means for holding said explosive means in a desired position on said pipe; means permitting said explosive means to be separated from the remainder of the apparatus lowered into the well; and means operable after the stuck point of said pipe is located for moving said explosive means to a joint above said struck point.

6. A method of locating the stuck point of a pipe in a Well and for promptly removing the free part of said pipe, said method including the steps of lowering into a well an instrument having stuck point determining means and an explosive, using said instrument to determine the stuck point of said pipe, locating the exposive at a desired position relative to said stuck point and securing said explosive to said pipe at said desired position, separating the stuck point indication means of said tool from said explosive, and igniting said explosive while said tool is still in said well.

7. An apparatus for salvanging pipe or casing from a bore hole comprising: a stuck point indicating device adapted to be lowered into the bore hole and having associated therewith surface apparatus by which the stuck point of the pipe is indicated; an explosive carried by said well tool; means for locating said explosive at a joint adjacent the stuck point of said pipe and for securing it to said pipe, said explosive and other parts of the well tool being separable from each other whereby said means for locating the stuck point may be removed from said explosive; and means operable from the surface of the ground whereby said explosive may be ignited without removing said indicating device from the well.

8. In a device for facilitating the selection and separation of a pipe at a collar connection comprising: a tubular member for attachment of means for lowering said device into a pipe string; a cup-shaped receptacle fixed to the lower end of said tubular member; an explosive jarring charge mounted in said receptacle; a plurality of spring fingers fixed on the outer peripheral wall of said receptacle; a locking plate mounted for longitudinal movement on said tubular member for locking said spring fingers in an inoperative position, said locking plate having equally spaced peripheral projections, said projections having openings to receive said spring fingers; and an electrically operated means for moving said locking plate out of engagement with said fingers whereby said fingers may engage in the collar joint of the pipe to be separated.

9. In a device for facilitating the selection and separation of a pipe at a collar connection, comprising: a tubular member having at its upper end an opening to receive means for lowering said device into a well, the lower end of said tubular member having a plurality of vertical slots; a cup-shaped receptacle fixed to the lower end of said tubular member; an explosive jarring charge mounted in said receptacle; a plurality of spring fingers fixed on the outer peripheral wall of said receptacle; a locking plate mounted for longitudinal movement on said tubular member for locking said spring fingers in an inoperative position, said locking plate having matching webs centrally located therein which are longitudinally moved in said slots in the lower portion of said tubular member, and equally spaced peripheral projections with slots to accommodate said spring fingers in an inoperative position; and an electrical means for moving said locking plate to an unlocked position whereby said spring fingers may engage a selected collar connection in said pipe string.

10. In a device for facilitating the selection and separation of a pipe at a collar connection, comprising: a tubular member for lowering said device into a pipe string; a cup-shaped receptacle fixed to the lower end of said tubular member; an explosive jarring charge mounted in 9 said receptacle; a plurality of spring fingers fixed on the outer peripheral wall of said receptacle; a locking plate mounted for longitudinal movement on said tubular member for locking said fingers in an inoperative position, said locking plate having equally spaced peripheral projections, said projections having openings to receive said spring fingers; and remote control means for moving said lock plate out of engagement with said fingers whereby said fingers may engage in the selection of a collar joint of the pipe to be separated.

11. A method for separating a stuck pipe in a Well above a stuck point so as to salvage the free pipe, all in such a continuous and rapid progression as to produce substantially continuous unity of operation which comprises the steps of: inserting and lowering a tool for locating a stuck point in a well in combination with an explosive charge; locating the stuck point of the pipe; determining, the position of the first free collar joint above the stuck point; engaging an explosive jarring charge to the pipe at said joint; remotely controlled releasing of said change for engagement withsaid first free collar connection; separating the measuring tool from said positioned charge and moving said tool to a safe area above the charge; and discharging said explosive whereby the free pipe may be separated at the desired point above the stuck point. 1 i

References Cited by the Examiner UNITED STATES PATENTS Greene 166-206 X Kinley 166*36 McCullough 166-35 Alexander 16'6 36 x Martin 73151 Martin 166--35 Brookes 73151 Sweetman 166- 630 X Carlisle 102-20 X Dill 166-1 Bender 73--15 1 Bell et a1 166142 X Davis 102-2l.8 X Sweetman 166 63 X Smith 102,-21 X Norman et al 102-20 X Johns 166--63 X CHARLES E. OCONNELL, Primary Examiner. BENJAMIN BENDETI, Examiner.

Claims

1. A METHOD FOR SEPARATING A STUCK PIPE ABOVE A STUCK POINT SO AS TO SALVAGE THE FREE PIPE, ALL IN SUCH CONTINUOUS AND RAPID PROGRESSION AS TO PRODUCE A SUBSTANTIALLY CONTINUOUS UNITY OF OPERATION WHICH COMPRISES THE STEPS OF: INSERTING A COMBINATION STUCK POINT MEASURING TOOL AND EXPLOSIVE DEVICE; LOCATING THE STUCK POINT OF THE PIPE; DETERMINING THE POSITION OF THE FIRST FREE COLLAR JOINT ABOVE THE STUCK POINT; POSITIONING AN EXPLOSIVE JARRING CHARGE AT THE SAID JOINT, WHEREBY THE SAID CHARGE MAY BE RELEASED TO ENGAGE SAID COLLAR JOINT; HOLDING SAID POSITIONED CHARGE IN PLACE WITH RESPECT TO THE PIPE; SEPARATING THE MEASURING TOOL FROM SAID POSITIONED CHARGE AND MOVING SAID TOOL TO A SAFE ABOVE THE CHARGE; AND DISCHARGE SAID EXPLOSIVE.

3. APPARATUS FOR LOCATING THE STUCK POINT OF PIPE IN A WELL, LOCATING EXPLOSIVE AT A JOINT ADJACENT THERETO, AND IGNITING SAME TO FREE THE JOINT, THE COMBINATION INCLUDING: STUCK POINT LOCATOR MEANS ADAPTED TO BE LOWERED INTO A WELL, INCLUDING MEANS WHEREBY THE STUCK POINT OF A PIPE MAY BE LOCATED, AND INCLUDING MEANS AT THE SURFACE OF THE WELL INDICATING WHERE SUCH STUCK POINT IS LOCATED; EXPLOSIVE