US3367179A

US3367179A - Free point indicator apparatus and method

Info

Publication number: US3367179A
Application number: US404224A
Authority: US
Inventors: Lawrence K Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-10-16
Filing date: 1964-10-16
Publication date: 1968-02-06
Anticipated expiration: 1985-02-06

Description

Feb. 6, 1968 1.. K. MOORE "3,367,179

FREE POINT INDICATOR APPARATUS AND METHOD Filed Oct. 16, 1964 3 Sheets-Shem l v 50A Z .0 19 "-6510 --&

Lawrence Moo/e INVENTOR ATTO/P/VEKS Feb. 6, 1968 L. K. MOORE 3,367,179

FREE POINT INDICATOR APPARATUS AND METHOD Filed Oct. 16, 1964 5 she ts-sheet s Afro/PM: m

United States Patent 3,367,179 FREE POINT INDICATOR APPARATUS AND METHOD Lawrence K. Moore, 3716 Ingold St., Houston, Tex. 77005 Filed Oct. 16, 1964, Ser. No. 404,224 7 Claims. (Cl. 73-151) This invention relates to new and useful improvements in free point indicator apparatus and methods.

In the drilling of wells, or in performing other well operations, the drill pipe, tubing or casing may become stuck at some point in the well, making it necessary to locate the free point above the stuck point so as to perform any one of the usual techniques for the recovery of the pipe. In the past, electrical indicating devices have been used in attempting to locate the stuck point and/or free point in a pipe which is stuck in a well. Such devices are expensive due to the special electrical equipment involved. Furthermore, since such special electrical equipment is used only for the free point indicator apparatus, it is not normally available at a well site, and therefore, it must be brought to each job when needed. The bulk of such equipment either necessitates the used of special trucks for housing it, or the time-consuming task of setting up the equipment at the well site must be undertaken.

It is an object of the present invention to provide a new and improved free point indicator apparatus for indicating the free point of a pipe which is stuck in a well.

An important object of this invention is to provide a new and improved free point indicator apparatus which is adapted to be lowered on and actuated by a non-electrical flexible line.

Another object of this invention is to provide a new and improved free point indicator apparatus which is actuable by a non-electrical wire line and which is capable of indicating longitudinal stretch and torque in a pipe so as to adequately inform the operator of the condition of the pipe at the free point.

A further object of this invention is to provide a new and improved free point indicator apparatus having a single sensing means for selectively sensing variations in both torque and longitudinal stretch developed in a stuck pipe.

Another object of this invention is to provide a new and improved method for locating the stuck point and/or the free point in a stuck pipe in a well by using an apparatus supported on a non-electrical flexible line.

Still another object of this invention is to provide a new and improved method for locating the stuck point and/ or the free point in a stuck pipe wherein measurements of both torque and stretch in a stuck pipe are made using apparatus supported on a non-electrical flexible line.

The preferred embodiment of this invention will be described hereinafter, together with other features thereof, and additional objects will become evident from such description.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, whereing an example of the invention is shown, and wherein:

FIG. 1 is a schematic view illustrating the apparatus of this invention in a test position prior to placing any stretch or torque in the well casing or pipe;

FIG. 2 is a view similar to FIG. 1, but illustrating the apparatus of this invention in a test position while the stuck pipe or casing is either being stretched or twisted;

FIG. 3 is a view, partly in elevation and partly in section, illustrating one form of the apparatus of this invention in detail;

FIG. 4 is a horizontal cross-sectional view taken on line 44 of FIG. 3;

3,367,179 Patented Feb. 6, 1968 FIG. 5 is an enlarged fragmentary view, partly in elevation and partly in section, of the sensing means of the form of the apparatus illustrated in FIG. 3, showing such sensing means in an open position prior to placing any stretch in the stuck pipe;

FIG. 6 is a view which corresponds with FIG. 5, but illustrates the sensing means in the test position after a longitudinal stretch has been applied to the stuck pipe;

FIG. 7 is a fragmentary sectional view illustrating a modified form of the sensing means of the invention in a position prior to applying any stretch or torque to the stuck pipe; and

FIG. 8 is a sectional view taken on line 8--8 of FIG. 7 to further illustrate the form of the invention shown in FIG. 7.

In the drawings, the letter A designates generally the apparatus of this invention which is adapted to be positioned in a pipe, casing or tubing P disposed in a well bore W. As illustrated in FIG. 1, the pipe P is stuck at a keyseat K or other restriction in the well bore W, and the purpose of the apparatus A is to locate the stuck point of the pipe P and the free point thereof above the stuck area. The present invention locates such free point with the use of a conventional non-electrical wire line L which is used for supporting and manipulating the apparatus A as will be fully explained hereinafter. At the surface of the well, an odometer D and a weight indicator S are provided for obtaining the readings and thereby the indications of the condition of the stuck pipe P at the various test points, as will also be more evident hereinafter.

Considering the invention more in detail, the apparatus A includes an upper set of drag springs 10 which is of conventional construction and serves to frictionally engage the inside of the pipe P. At the lower end of the apparatus A a plurality of drag springs 20 is provided which is likewise of conventional construction and is adapted to engage the inside of the stuck pipe P with a frictional force. The drag springs 10 are shown by way of example only since other friction means may be employed, but specifically in FIG. 3 one form of drag springs 10 is shown having the bowed resilient steel springs 10 which are secured at their bottom ends to a body sleeve 11 by screws 10a or similar fastening means. The upper ends of the drag springs 10 are preferably secured to a slidable ring 10b by screws 10c so that the drag springs 10 may readily flex radially and thereby have some longitudinal movement at the upper ends. A coil spring 12 facilitates the flexibility and the outward radial expansion of the drag springs 10 to maintain the frictional contact with the inside surface of the pipe P. The drag springs 20 are shown in FIG. 1, but they are not shown in the same detail as the drag springs 10 since they are identical therewith other than being upside down as compared to the springs 10. Thus, the drag springs 20 are fixed at their upper ends 20a by any suitable means and they are slidable at their lower ends 201) with a spring 21 serving to resiliently urge the sliding ends 20b upwardly to facilitate the frictional engagement of the drag springs 20 with the inside surface of the pipe P.

The drag springs 20 are mounted on the upper body section which includes the tubular sleeve or body member 11, a coupling element 14 and a connector sleeve 15.

The lower drag springs or friction elements 20 are mounted on the lower body section which includes a tubular body element 17 (FIGS. 1 and 3), a coupling 18, another coupling 19, and a connecting sleeve 16.

The upper body section with the springs 10 mounted thereon is adapted to move both longitudinally and rotationally with respect to the lower body section having the springs 20 thereon. Such longitudinal and rotational movement is permitted because of the co-actionbetween one or more laterally extending keys 15a which extend into an annular groove 16a. Thus, the keys 15a permit relative rotation between the connecting

sleeves

15 and 16 while limiting the longitudinal movement therebetween so as to prevent the separation of the upper and lower body sections of the apparatus A. Thus, it is to be noted that the sleeve 16 has an upper shoulder 16b which serves as a stop or limit for the upward movement of the key or keys 15a since the surface 15b of the key or keys 15a engages the surface 16b for such stopping action.

Rotational movement is also limited as between the

coupling sleeves

15 and 16 in the preferred form of the invention by the use of downwardly depending lugs 15c which project into slots 22a in a wedge element 22 of the sensing means 30, as will be more fully explained.

The sensing means 30 is capable of sensing, or reacting to, changes in either longitudinal stretch in the pipe P or torque developed in the pipe P between the

drag springs

10 and 20. The wedge means 22 of the sensing means 30 is preferably a ring which is formed with an inner upwardly and inwardly tapered surface 22b. Such wedge ring 22 is firmly secured against movement to the lower body section by the coupling members 18 and 19 (FIGS. 3 and A plurality of sensing elements or dogs 25, each of which has an outer inclined surface 25a thereon for engagement with the inner surface 22b, is mounted for movement relative to the Wedge means 22. The inner surface 251) of each sensing element or dog 25 is tapered upwardly and inwardly for a purpose to be hereinafter explained. As illustrated in FIG. 4, the preferred form of the invention has three of such sensing elements or dogs 25 which together define a central bore or opening 26 which is of a variable size depending upon the positions of the sensing elements or dogs 25.

When there is no stretch or tongue force acting on the apparatus A through the pipe P, the dogs 25 are in their opened position (FIGS. 3 and 5). At the same time, the element 15 is telescoped or closed with respect to the element 16 as illustrated in FIG. 5, and the lugs 150 are in the position shown in FIGS. 35. Preferably, a spring 29 having its upper end 29a connected to the sleeve 15 and its lower end 2912 connected to the sleeve 16 is provided for urging the

sleeves

15 and 16 relative to each other to the position shown in FIGS. 35, as will be more evident hereinafter.

For moving the sensing dogs or elements 25 inwardly to vary the diameter of the bore 26 in response to changes in the stretch and/or torque in the pipe P, each of the dogs 25 is pivotally connected to the wedge ring 22 by a link 31. The link 31 has a pivot pin 13a for pivotally connecting the upper end of the link 31 to the ring 22. A pivot pin 31b extends through an elongated slot 310 at the lower end of each link 31 as best seen in FIG. 5 to permit the pivoting of the link 31 relative to the dog 25 while the dog 25 is moving radially or laterally. The link 31 also has a slot 31d formed in its central portion for receiving a pivot pin or connector pin 3211 on the lower end of an operating rod 32. The operating rod 32 extends upwardly through a guide hole 220 formed in the ring 22. The upper end of the rod 32 has a roller 33 rotatably mounted thereon and extending laterally outwardly into an arcuate upwardly inclined groove 15d formed in the sleeve 15. Such roller 33 is adapted to stay in the bottom part of the groove 15d during the longitudinal movement of the sleeve 15 upwardly with respect to the sleeve 16, without any rotation or torque. However, upon the application of a torque or rotation movement of the

sleeves

15 and 16 with respect to each other from that position shown in FIG. 5, the roller 33 is adapted to move upwardly in the groove 15d to cause an upward travel on the rod 32. Thus, whether there is a longitudinal movement of the sleeve 15 relative to the sleeve 16, or a rotational movement of the sleeve 15 relative to the sleeve 16, such movements are translated into a longitudinal movement of the rod 32 and thus movements of the sensing dogs 25, as will be more fully explained. The upward travel of the rod 32 may be limited by a stop ring 3221 which is adapted to engage the surface 22d to limit such upward travel of the rod 32.

A spring 35 (FIG. 5) is preferably mounted in each recess 22e of the ring 22. Such spring 35 is a stretch spring having its ends physically welded or otherwise connected to the link 31 and the ring 22. The spring 35 is in a neutral condition when the sensing elements or dogs 25 are in the opened position of FIG. 5, but when the dogs 25 are moved upwardly and inwardly from the position of FIG. 5, the spring 35 is stretched so as to apply a returning force on the links 31 and the dogs 25 to return them to the opened position when the position of the arm 32 permits. Such ring 35 is normally not necessary, but it serves to facilitate a retraction of the dogs 25 under some circumstances.

A control or measuring rod 40 is positioned throughout the length of the tool or apparatus A and it has an upper section 40a of a uniform diameter which is less than the maximum inner bore diameter of the bore 26 when the dogs 25 are in their fully closed position. The rod 40 also has a lower tapered section 40b which preferably has the same angle of taper as the inner tapered surfaces 25b on the dogs 25.

The upper end of the control rod 40 is connected by means of a rope socket or other connector 42 to the wire line L. Conventional weights and jars may be connected at the upper end of the control rod 40, but with the apparatus A of this invention they are not normally necessary.

If it is desired to provide additional weight for the lowering of the apparatus A into the pipe P to overcome the frictional resistance of the drag springs 10 and 20, additional weight may be added as indicated by the dotted line at 44 in FIG. 1. Such weight 44 is added to the lower end of the control rod 40 so that when the rope socket 42 or other structure (FIG. 3) is in contact with the upper end of the body sleeve 11, the weight 44 is serving to act downwardly on the entire apparatus A for moving same downwardly in the well pipe P.

Also, the lower end of the control rod 40 has a stop nut or member 400 which is adapted to engage a stop surface 18a (FIGS. 13) when the control rod 40 has been moved upwardly to its maximum extent.

In carrying out the method of this invention, using the apparatus A, such apparatus A is lowered into the well pipe P to a position at which it is desired to test the pipe P to determine whether it is free or stuck. Generally, the apparatus A is initially lowered into the free portion of the pipe P and several readings are taken in such free portion to obtain an average indication in the free portion of the pipe before lowering the apparatus A into the stuck portion of such pipe.

In any event, when the apparatus A has been lowered into the pipe to a test position, the non-electrical flexible line L is slacked off and the weight of the apparatus A is sufficient to cause it to slide downwardly in the pipe P to a desired location when the weight of the control rod 40 is acting downwardly by the engagement of the rope socket 42 or other connector at the lower end of the wire line L. During such lowering movement of the apparatus A, the sensing means 30 is maintained in the opened positioned by the spring 29.

When the apparatus A has reached its test position, the wire line L is pulled upwardly until the stop nut or member 40c engages the stop surface or element 18a. At that time, the weight of the rod 40 and anything connected directly to the line L is indicated on the weight indicator S at the position shown in dotted lines 50a. An additional strain is then taken on the wire line L so that the weight indicator shows such additional strain at 5017. The odometer D is then read or is otherwise suitably recorded. As

shown in FIG. 1, by way of example, the odometer has a reading of 6510 when the control rod 40 is in the uppermost position prior to any stretch or torque being placed in the pipe P.

Thereafter the wire line L is slacked or lowered for approximately the length of the tapered portion 40b of the rod 40. Such length may vary, but normally it will be about ten feet in length and therefore the wire line L is slacked downwardly at least about ten feet in the usual case.

The pipe P may then be either stretched by a longitudinal pull at the surface of the well in the known manner, or the pipe P may be rotated to apply a torque thereto. For purposes of explanation, it is assumed that the stretch test is conducted first.

In such case, if the entire apparatus A is in the free port-ion of the pipe P, or if at least the upper springs are in the free portion of the pipe P, the upper body section will be pulled upwardly relative to the lower body section of the apparatus A. In other words, the upper drag springs 10 will be moved upwardly relative to the lower drag springs 20 so long as at least the upper drag springs 10 are in a free portion of the pipe P. The upward movement of the drag springs 16" causes an upward movement of the control sleeve which results in pulling the rod 32 upwardly for each link 31. The links 3-1 are then moved upwardly about their pivot points 3101 to cause the sensing elements or dogs 25 to move upwardly and inwardly to thereby reduce the diameter of the central bore 26 defined by such dogs 25. The extent to which the diameter of the bore 26 is changed will depend upon the amount of stretch between the upper drag springs 10 and the lower drag springs 20. It is normal to apply about thirtyfive thousand pounds pull on a four and one-half inch pipe. Other amounts of pull are used for other sizes of pipe and of course the pull may be varied for any size of pipe.

Thereafter, while the pipe P is thus subjected to the longitudinal pull, the wire line L is again picked up until the weight indicator reads the same amount as indicated at 5%. At that time, the odometer D is again read. If there has been a stretch in the pipe P between the drag springs 10 and 20, the bore 26 will have been reduced in diameter and thus the tapered portion 40b will engage the inner surfaces 2512 before the stop member 400 engages the stop element 18a (see FIG. 2) which results in the reading 50b being obtained before the wire line L has been raised upwardly to the same extent as prior to the stretching of the pipe P. Thus, as indicated in FIG. 2 the odometer may read 6515 which indicates that more of the line L is in the pipe P than when the pipe P was first tested without any stretch or pull thereon. The difference between the readings obtained in the two positions is an indication of the amounts of stretch in the pipe P between the drag springs 10 and When it is desired to move the apparatus A to a different location in the pipe P, the line L is again slacked off so that the weight of the rod 40 is applied to the apparatus A to move same. It should be noted that when the weight of the rod 40 is applied to the drag springs 10 and 20, they are released from their frictional engagement as they slide in the pipe P so that the spring 29 can return the

sleeves

15 and 16 to the relative positions shown in FIG. 5 and thereby return the dogs to the open position of FIG. 5. In that position, the apparatus A may be lowered to new positions for further tests, or it may be retrieved from the well pipe P.

If a torque reading is to be taken, the same procedure as set forth above is followed, except that the pipe P is rotated or twisted at the surface of the well so as to put a torque or twist in the free portion of the pipe P. If the upper drag springs 10 are in the free pipe portion, the sleeve 15 will be turned relative to the sleeve 16 so as to cause each roller 33 on each rod 32 to roll upwardly in its respective inclined guide slot 15d. Such upward movement of the rods 32 causes a corresponding inward movement of the dogs 25 to reduce the size of the central bore 26. Therefore, when the line L is again pulled upwardly to obtain the strain reading at 50b, the line L will show a higher reading as indicated in FIG. 2, reflecting that more line L is in the pipe P than prior to applying torque to the pipe.

It will be understood that a plurality of readings, in stretch and/or torque is generally employed to learn the true condition of the pipe P with regard to its stuck point, any partially stuck area and the free point. The torque and stretch readings may be taken in either order, or in any sequence desired with the apparatus of this invention.

In FIGS. 7 and 8, a modified sensing means is indicated at 130. Such sensing means 130 has a plurality of sensing elements or dogs 125, preferably three in number and spaced in the same manner as the dogs 25 (FIG. 4) so as to form a central bore 26 through which the rod 40 is adapted to extend in the same manner as heretofore described in connection with the sensing means 30. Each of the sensing elements or dogs is mounted on a fixed support 70 which is suitably slotted at 70a for each of the sensing elements 125. Each sensing means or dog 125 is supported for radial or lateral movement relative to the support 70 by means of a retaining pin 72 which preferably has a rectangular or square cross section so as to guide the movement of its respective dog 125. Such pin 172 fits within a slot 125a in each dog 125 so that the square or rectangular shape of the pin 72 guides the dog 125 and prevents it from pivoting or tilting during its radial movement. The inner surface 125b of each of the dogs 125 is tapered downwardly and outwardly, at the same taper as on the tapered section 40b of the control or measuring rod 40. The inner surface 125c of each of the dogs 125 is inclined upwardly and outwardly for engagement by an inclined surface 122a of a wedge member 122 so that as the wedge member 122 moves upwardly with respect to the dog 125, the dog 125 is forced towards the center or inwardly so as to reduce the diameter or size of the opening 26.

To accomplish nuch movements of the wedge member 122, a link 131 is pivotally mounted thereto and to an operating rod 132. A link 131 is pivotally connected at pivot pin 131a to the circular portion 70b of the support 70 (FIG. 8). The lower end of each link 131 is pivotally connected to the wedge means 122 at a pivot pin 131b which operates within a slot 1310. It is to be noted that each of the dogs 125 is in a position to co-act with a wedge means 122 and therefore each wedge means 122 has operably connected therewith an operating rod 132, one of which is illustrated in FIG. 7.

The operating rod 132 operates in the same manner as heretofore described in connection with the operating rod 32 of FIGS. 36. Thus, the operating rod 132 has a roller 33 thereon which is adapted to move within a slot 15d upon the application of a rotational or twist force to the pipe P between the drag springs 10 and 20. The lower end of the rod 132 is connected by a pivot pin 132a to the link 131 by the extension of such pin 132a through a slot 131d.

The form of the invention illustrated in FIGS. 7 and 8 is thus substantially the same as the form shown in FIGS. 3-5, except for the sensing means which ditfers as explained above from the sensing means 30. However, the sensing means 130 is also adapted to be used for obtaining indications of either stretch or torque condition in the pipe P between the upper and lower drag springs. The dogs 125 of the sensing means 130 are in the closed position, that is, they have the smallest possible diameter under normal circumstances when initially running the apparatus into the well. For the purposes of explaining the use of the apparatus of FIGS. 7 and 8, it will be assumed that the apparatus thereof has been incorporated into the apparatus A in FIGS. 1 and 2 in place of the sensing means 30. Therefore, when the apparatus is lowered to the position shown in FIG. 1 for the beginning of a test in the pipe P, and prior to the taking of any weight on the line L, the dogs 125 are in their maximum closed position shown in FIGS. 7 and 8.

Then, the wire line L is pulled upwardly to move the control rod 40 upwardly until the weight indicator S is indicating that a strain in addition to the weight is being taken by the line L. Thus, the weight indicator would read at 50b as shown in FIG. 1. Under such circumstances, the operator knows that the control rod 40 is in contact with the dogs 125, usually in the upper part of the tapered portion 40b of the rod 40. The operator then takes a reading on the odometer D, and without releasing the strain on the line L or slacking off in any amount, the stretch may be applied to the pipe P at the surface. When the desired predetermined amount of stretch is placed in the pipe P, the weight indicator Will show that the strain has been taken off of the line L due to the opening of the dogs 125 when the stretch occurs. Thus, when the stretch in the pipe P occurs, the operating rod 132 is moved upwardly since the roller 133 is pulled upwardly in the bottom of the slot 15d as the sleeve 15 moves upwardly relative to the sleeve 16. The upward movement of the rod 132 for each wedge means 122 causes an upward movement of each wedge 122 and this permits a retraction or an outward movement of each dogs 125 to enlarge the diameter of the bore 26. By reason of such enlarged diameter, the tapered portion 40b of the rod 40 can then move further upwardly before contact is made with the surfaces 125!) and further upward movement of the rod 40 is prevented. The extent to which the upward movement is permitted is indicated on the odometer D, thereby indicating the extent to which stretch has been placed in the portion of the pipe between the drag springs 10 and 20. If stretch is indicated by such readings on the odometer D, the operator knows that at least the upper drag springs 10 are in the free portion of the pipe, but on the other hand, if no stretch is indicated, the operator knows that the upper drag springs 10 and the lower drag springs 20 are both in the stuck portion of the pipe.

In order to take the torque reading, or a subsequent stretch reading, the wire line L is slacked off or lowered so that the Weight of the rod 40 causes the tool A to move downwardly enough to release the drag friction on the upper and lower drag springs 10 and 20. Such release of the frictional contact with the pipe P allows the spring 29 to return the elements and 16 to their starting position shown in FIGS. 7 and 8 wherein the minimum diameter for the opening 26 is provided.

If a torque reading is to be taken, the same procedure set forth above is followed which includes pulling up on the control rod until the additional strain indicated at 50b is obtained on the weight indicator and then after a reading of the odometer D is obtained, the torque is put into the stuck pipe. If the torque is developed between the drag springs 10 and 20, such torque will result in a movement of the roller 33 upwardly in the slot 15d. As each roller 33 moves upwardly relative the slot 15d, its rod 132 is moved upwardly to raise the wedge means 122 and allow the dogs 125 to retract to again open the bore of the central hole or bore 26. During the developing of the torque in the pipe P, the wire line L is not slacked off and in some cases a steady pull may be applied, but in any event, the enlargement of the bore 26 permits the rod 401; to move upwardly a greater distance than when no torque was in the pipe P. Therefore, when the torque has been developed in the pipe P between the drag springs 10 and 20, the line L is again pulled to obtain the strain indicated at 50b and the odometer reading is made to determine the change in the length of the line L from the first to the second reading. The difference between the first and the second reading on the odometer D is an indication ofthe amount of torque 0r twist applied to the pipe P between the drag springs 10 and 20.

It is to be noted that the stop flange 1321; on the rod 132 is adapted to engage the surface 122d so as to limit the amount of upward movement of the rod 132. The stops 13211 in FIG. 7 and 32b in FIG. 5 serve to limit the extent of the upward travel of the rod 132 should both a torque and a stretch be applied in the pipe P at the same time.

When it is desired to remove the tool of FIG. 7 and FIG. 8 from the pipe P, a greater force is applied in lifting upon the wire line L than is normally used in testing so as to force the dogs 125 to move to their fully opened position. Such movement of the dogs 125 radially outwardly causes an upward travel of the wedge means 122 and the rods 132 for rotating the

elements

15 and 16 relative to each other and also to move the drag springs 10 and 20 relative to each other. In that way, the tapered rod 40 can move upwardly until the stop at its lower end engages a stop on the lower end of the body section to enable the tool to be fully removed from the pipe P.

It is to be noted that the apparatus A in both forms is shown without the provision for a sealing means to seal off the well fluid from the working components of the sensing units, but it will be understood that such sealing arrangements can be employed in the event they are desirable for deeper drilling and sandy well conditions.

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.

What is claimed is:

1. Free point indicator apparatus, comprising:

(a) a tubular body adapted to be lowered into the bore of a pipe which is stuck in a well,

(b) a flexible non-electrical line connected to said tubular body for lowering the body into the stuck (0) said body having an upper body section and a lower body section with means for permitting limited relative longitudinal movement therebetween,

(d) an upper friction means on said upper body section for frictionally engaging the stuck pipe,

(e) a lower friction means on said lower body section for frictionally engaging the stuck pipe,

(f) sensing means having a variable sized opening which is operable to vary the size of such opening in response to longitudinal movement or torque developed in the stuck pipe between the upper and lower friction means, and

(g) a control rod extending through said opening of the sensing means and operably connected to the flexible non-electrical line for co-action with said sensing means to obtain an indication of the amount of longitudinal movement in the stuck pipe between the friction means when the pipe is longitudinally moved and to obtain an indication of the amount of torque in the stuck pipe between the friction means when torque is applied to the pipe.

2. Free point indicator apparatus, comprising:

(b) a flexible non-electrical line connected to said tubular body for lowering the body into the stuck pipe,

(c) said body having an upper body section and a lower body section with means for permitting limited relative longitudinal movement therebetween,

(f) a variable bore sensing means operable to vary the size of the bore in response to either longitudinal stretching or twisting of the pipe between the upper and lower friction means, and

(g) a control rod operably connected to the flexible non-electrical line and movable in the bore of said sensing means for different distances depending on the size of the variable bore to thereby indicate variations in the condition of the pipe when subjected to stretching or torque.

3. Free point indicator apparatus, comprising:

() said body having an upper body section and a lower body section with means for permitting limited relative longitudinal movement therebetween,

(g) a control rod having sections of different diameters and longitudinally movable in the bore of the sensing means until the diameter of the control rod corresponds with the diameter of the bore for obtaining indications of either the stretch or the torque in the pipe.

4. Free point indicator apparatus, comprising:

(g) a control rod having a tapered section and longitudinally movable in the bore of the sensing means until the diameter of the control rod corresponds with the diameter of the bore for obtaining indications of either the stretch or the torque in the pipe.

5. Free point indicator apparatus, comprising:

(b) a flexible non-electrical line connected to said tubular body for lowering the body into the stuck pipe. (c) said body having an upper body section and a lower body section with means for permitting limited relative longitudinal movement therebetween,

(f) sensing means having a variable sized opening which is operable to vary the size of such opening in response to longitudinal or rotational movements of the upper and lower body sections relative to each other, and

(g) a control rod extending through said opening of the sensing means and co-acting with the sensing means for indicating said longitudinal movement in the pipe between the upper and lower friction means when the pipe is longitudinally moved and to indicate the amount of torque in the pipe between the upper and lower friction means when torque is applied to the pipe.

6. Free point indicator apparatus, comprising:

(b) a flexible non-electrical line connected to said tubular body for lowering the body into the stuck pipe, (c) said body having an upper body section and a lower body section with means for permitting limited relative longitudinal movement therebetween,

(f) a plurality of sensing dogs disposed in the body to form a central bore therebetween,

(g) means for mounting said dogs for lateral movemen-ts to vary the size of the central bore therebetween, and

(h) a measuring rod having different diameter sections longitudinally movable in said bore for different distances depending upon the size of said bore.

7. Free point indicator apparatus, comprising:

(g) wedge means co-actin'g with said dogs in response to longitudinal stretching ora torque developed in the stuck pipe between the friction means for varying the size of the central bore defined by the sensing dogs, and

References Cited UNITED STATES PATENTS 2/1944 Mestas. 7/1963 Rogers 73-151 J. W. MYRACLE, Assistant Examiner.

Claims

1. FREE POINT INDICATOR APPARATUS, COMPRISING: (A) A TUBULAR BODY ADAPTED TO BE LOWERED INTO THE BORE OF A PIPE WHICH IS STUCK IN A WELL, (B) A FLEXIBLE NON-ELECTRICAL LINE CONNECTED TO SAID TUBULAR BODY FOR LOWERING THE BODY INTO THE STUCK PIPE, (C) SAID BODY HAVING AN UPPER BODY SECTION AND A LOWER BODY SECTION WITH MEANS FOR PERMITTING LIMITED RELATIVE LONGITUDINAL MOVEMENT THEREBETWEEN, (D) AN UPPER FRICTION MEANS ON SAID UPPER BODY SECTION FOR FRICTIONALLY ENGAGING THE STUCK PIPE, (E) A LOWER FRICTION MEANS ON SAID LOWER BODY SECTION FOR FRICTIONALLY ENGAGING THE STUCK PIPE, (F) SENSING MEANS HAVING A VARIABLE SIZED OPENING WHICH IS OPERABLE TO VARY THE SIZE OF SUCH OPENING IN RESPONSE TO LONGITUDINAL MOVEMENT OF TORQUE DEVELOPEND IN THE STUCK PIPE BETWEEN THE UPPER AND LOWER FRICTION MEANS, AND