US3585857A

US3585857A - Free point indicator apparatus

Info

Publication number: US3585857A
Application number: US791902*A
Authority: US
Inventors: Lawrence K Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-01-17
Filing date: 1969-01-17
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22

Abstract

An improved free point indicator apparatus for indicating whether pipe in a well is free or stuck at particular elevations. A tapered, notched control rod coacts with a pivoted catch finger to indicate relative movement between two pipe sections.

Description

[72] Inventor Lawrence K. Moore [56] References Cited 243 Willow Bend, Huntsville, TEX. 77340 UNITED STATES PATENTS "if; 3 1,126,554 1/1915 Murray 33/1265 [22] d 3,117,445 1/1964 Brown et 31.. 73/1515 [451 3,331,243 7/1967 Moore 73/151 Primary Examiner-Jerry W. Myracle Attorney-Pravel, Wilson & Matthews [54] FREE POINT INDICATOR APPARATUS 6 Claims 13 Drawing Figs ABSTRACT: An improved free point indicator apparatus for [52] U.S. 73/151 indicating whether pipe in a well is free or stuck at particular [5 1] Int. Cl E2lb 47/12 elevations. A tapered, notched control rod coacts with a [50] Field of Search 73/l5l; pivoted catch finger to indicate relative movement between two pipe sections.

PATENTED M22 1911 SHEET 1 [IF 4 law/e009 A. Moore INVEN'IOR PATENTEU JUH22 [9?] SHEET 2 OF 4 lam/fence M Moore lNI ENTOR "(a Jan hone] & MaHLewA 14 TTOR NF YS PATENTEU JUN22 ls'n SHEET 3 OF 4 1 MW M. M 55 K Z W INVENTOR madam m"! WilAmv (L MaffLewA ATTORNEYS PMENFEUJUNZE 197:

SHEET 4 0F 4 JNV EN TOR Zawrence K Moore Hegel awl/l will & MaflLewA ATTORNEYS FREE'POINT INDICATOR APPARATUS BACKGROUND OF THE INVENTION The field of the invention is free point indicator apparatus for locating the elevationat which pipe is stuck in a well.

In my US. Pat. Re. No. 26,458, apparatus for indicating the free and stuck portions of well pipe is disclosed. The present invention is another embodiment of such apparatus.

SUMMARY OF THE INVENTION The present invention relates to an apparatus for determining the elevations of stuck and free portions of pipe in a well, and particularly for multiplying a relatively small amount of stretch in pipe intoa reading on a meter at the surface. Because of the construction of the apparatus, as explained in detail hereinafter, the tool may be left exposed to the mud or fluid in a well with a minimum of danger of sanding up of the parts, whereby the tool is dependable and accurate. Also, the construction includes a coacting finger and a tapered notched rod which is engaged thereby so as to minimize any tendency to wedge such parts together when obtaining a measurement with the tool. With the apparatus of this invention, the extent of stretch can be accurately indicated on a meter at the surface so that the operator can more readily and accurately locate the point or area at which the pipe is stuck. The longitudinal movement of the wire line is correlated mechanically with a meter at the surface for indicating on the meter'the stretch, if any, in the pipe upon manipulating the wire line.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view, partly in elevation, illustrating the free point indicator apparatus of this invention;

FIG. 1A is an isometric view of the meter which is shown without a cover in FIG. I;

FIGS. 2A, 2B, 2C, and 2D are views, partly in elevation and partly in section, illustrating essentially the entire free point indicator tool of this invention from its upper to its lower end, respectively, with the parts in position prior to stretching the pipe in which the tool is disposed;

FIG. 3 is a vertical sectional view, partly in elevation, taken on line 3-3 of FIGS. 2A and 28;

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

FIG. 5 is a sectional view taken on line 5-5 of FIG. 3;

' FIG. 6 is a sectional view taken on line 6-6 of FIG. 3;

FIG. 7 is a sectional view taken on line 7-' of FIG. 3;

FIG. 8 is a view, partly in elevation and partly in section, illustrating the midportion of the free point indicator tool of this invention after the pipe in which the tool is located has been stretched; and

FIG. 8A is a view illustrating the preferred form of the finger for the indicator tool of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, the letter T designates generally the free point indicator tool or apparatus of this invention which is adapted to be lowered into a well pipe or casing C disposed in a well bore W. The indicator tool T is lowered on a flexible line L which extends to the surface and is passed over a conventional measuring wheel M and through a conventional weight indicator B. A meter F, a portion of which is schematically illustrated in FIG. 1, is operably connected to the measuring wheel M for indicating the amount of stretch, if any, in the pipe or casing C during each test, as will be more fully explained.

Considering the invention more in detail, the free point indicator tool T includes an upper section S (FIG. 2A) and a lower section S-l (FIGS. 28, 2C, 2D). As will be explained,

such sections S and S-l are longitudinally movable a limited ventional friction means R which is adapted to engage the inside of the pipe or casing C, and the lower section 8-] has a similar friction means R-l for also engaging the inside of the casing or pipe C, whereby a stretching of the pipe or casing causes the upper section S to move upwardly relative to the lower section 5-1. A stretch response means K which includes a control rod 10 (FIG. 1) is provided with the tool T for multiplying the amount of movement of the upper section S relative to the lower section S-l during the stretching of the casing C, as will'be more fully explained. The movement of the stretch response means is transmitted to the surface by the wireline or the other flexible line L, as explained hereinafter.

The upper section S includes a tubular body 12 having a window 12a therein and terminating at its lower end 12b (FIG. 2B). A stop block 14 is mounted at the upper end of the window 12a (FIG. 2) by means of retaining screws 14a or other suitable securing means. Such stop block 14 has a curved stop surface 14b thereon which will be referred to in more detail hereinafter. A limit ring 15 is threadedly engaged inside of the body or housing 12 and is provided with an upper stop shoulder 15a for purposes to be hereinafter described. The upper end of the sleeve or body 12 is threaded to an adapter and then to an extension 12d which carries the conventional friction bow springs R above a conventional coil spring 16. The coil spring 16 may be adjusted by an adjustable retaining nut 16a threaded on the extension 12d. Since the friction bow spring construction R is conventional and is essentially as illustrated for the friction means R-l shown in FIG. 2D for the lower end of the tool T, the details of such construction R have not been shown. The upper end of the upper section S has a suitable head l2e (FIG. 1) which preferably includes a typical fishing neck for retrieving the tool T from the pipe or casing C with a conventional fishing tool if such becomes necessary or desirable.

The lower section 8-] includes a tubular body 20, the details of which can best be seen by viewing both FIGS. 2A and 3, which boy 20 extends upwardly within the body or housing I2 of the upper section S. The body 20 is threaded on its external upper surface 2021 for receiving an adjustable limit nut 21 (FIGS. 2A, 3 and 4), which has a lower shoulder 21a which is adapted to engage the upper shoulder 15a of the limit ring 15 on the upper section S to limit the extent of longitudinal movement of the section S and 3-1 away from each other. The threaded sleeve or limit ring 21 is adjustable to control the extent of such relative longitudinal movement between the sections S and 8-1.

It is to be noted that the body 20 is formed with a rectangular slot 20b (FIG. 4) which is adapted to accommodate the square shape of the control rod 10 and also to provide for a slot which extends to a point of alignment with the window 12a in the body or housing 12.

The body 20 has a recess 200 formed therein for receiving a guide ring 22 which has a square bore 22a for sliding engagement with the external surface of the control rod 10, so as to maintain the control rod 10 in a centered position within the body of the tool T during the longitudinal movement of the rod 10 relative to the rest of the tool T. Below the guide ring 22, the lower section 8-1 is continued from the body 20 by means of an adapter 23 which is threaded or is otherwise secured to the lower end of the body 20, and which has threaded thereto a tubular body 24 (FIGS. 23 and 2C). The lower end of the tubular body or sleeve 24 is threaded or is otherwise connected to a connector 25 which is internally threaded and which receives the lower threaded tube or sleeve 26 which extends to the bottom of the tool and preferably terminates in a lower closure 26:: (FIG. 1). The tube 26 carries an adjusting nut 27 for adjusting the compression of a coil spring 28 of conventional construction which is used in conjunction with the sliding bow springs 29 which are mounted on a slidable ring 30 at the upper ends and are fixed to a fixed ring 32 at their lower end. Thus, as is well understood, the spring 28 is under compression so as to maintain the springs 29 bowed outwardly for frictional engagement with the inside of the casing or pipe C, but due to the longitudinally sliding ring 30 on the upper ends of the springs 29, the spring 28 may be further compressed to yield in response to different sizes of pipe or casing C. The same general construction as is illustrated for the friction means R-l may be used for the friction means R, but it will be understood that the bow springs 29 of the friction means R would be above the coil spring 16, which thus serves the same purpose as the spring 28 of the friction means R1.

The control rod is preferably of a square shape so that it does not rotate relative to the rest of the tool T. However, other suitable shapes or means may be employed to permit longitudinal movement of the control rod 10 relative to the rest of the tool without permitting relative rotation therebetween. The control rod has a rope socket 101: (FIG. I) or other suitable means for connecting same to the lower end of the wire line or cable L. The wire line or cable L is preferably of the nonelectrical type known as a slick" line, but such line L could be an electrical line if it is desired to use electricity down in the well for electrical tools or for other purposes. In any event, the line L should be strong enough to support the tool T and to manipulate same for obtaining the measurements or indications on the meter F as will be explained. I

The control rod 10 extends downwardly throughout substantially the full length of tool T and it terminates in a lower stop 10b having a shoulder Mic. The shoulder 10c may be formed by machining the lower stop 10b in a square shape but turned one-eighth or other part of a revolution as compared to the square rod 10 thereabove. Such stop shoulder 10c is adapted to engage a lower shoulder 22b on the guide ring 22, or any other suitable stop surface, as will be explained.

The control rod 10 carries a plurality of notched strips or plates 30 which are connected to a reduced thickness portion of the control rod 10 by means of a suitable screws 31 or other retaining means. As best seen in FIG. 2B, the rod is tapered on one surface thereof downwardly and inwardly as indicated at 10b, and is then formed with a recess 10c for receiving the notched plates or segments 30. The inner surface of the recess 100 is preferably tapered or formed at an angle with respect to the central axis of the rod 10 so that the notches in the plates 30 are aligned at an angle with respect to the longitudinal axis or centerline of the rod 10, with the upper most notch 30a being disposed at a greater lateral distance from the lower pointed end 35a of catch finger 35 (FIG. 2A) than the lowermost notch 30b and the intermediate notches 30c below the upper notch 30a. The notches 30: below the upper notch 30a are progressively closer in a lateral direction to the finger 35 so that the lowermost notch 30b is the closest in a lateral direction to the finger 35 (FIG. 2B). The particular construction for obtaining the gradually increased angle of the notches from the uppermost notch 30a to the lowermost notch 30b can be accomplished with constructions different from that illustrated, but the construction illustrated is convenient for machining and assembly purposes.

The catch finger 35 is pivotally mounted on the body by pivot pins 36 which extends through two spaced lugs 35b (FIGS. 2A, 3 and 7) which are integral with the finger 35. The finger 35 is provided with an upper inclined surface 35c (FIG. 2A) which is engaged by pivoted levers 38 which are mounted as a unit on pivot pins 39 disposed in the body 20 (FIGS. 3 and 6). The levers 38 are pivoted to urge the finger 35 outwardly at its upper end and inwardly at its lower end (clockwise as viewed in FIG. 2A) by means ofa pair of springs 40 which are mounted on pins 41 to the body 20 and are secured to the lugs 38. The springs 40 are always in a stretched or tension condition, with the maximum stretch being in the retracted or closed position of the finger 35 as illustrated in FIG. 2A.

The upper surface 35d of the finger 35 moves into contact with the stop surface 14b after the rod 10 is raised a sufficient distance so as to allow the lower end 35a to move inwardly. Such inward movement of the end 350 occurs as the control rod is moved upwardly to dispose the tapered surface 10b opposite the finger 35. The extent of the movement of the finger 35 thus depends upon the extent ofthe longitudinal movement of the upper section S with respect to the lower sections S1, as will be explained hereinafter.

The meter F used at the surface is of importance in the present apparatus since it provides a visual indication of the actual stretch of the pipe or casing C in fractions of an inch for each test. The meter F has been shown schematically in FIG. 1 wherein a gear 50 on a gear shaft 51 is representative of a gear reduction and drive shaft from the measuring wheel M. In practice, the shaft 51 is connected through suitable gearing to the shaft 55 of the measuring wheel M, but as illustrated in FIG. 1, the shaft 51 is shown as being driven from such shaft 55 by a chain or belt 56 which passes over a wheel or sprocket 57 on the shaft 51, and also a suitable sprocket (not shown) on the shaft 55. The gear 50 is connected to a gear 60 on a shaft 61 having a control knob 61a and a pointer 61b therewith. A spring 62 urges the gear 60 into mesh with the gear 50, but by pulling on the knob 6111, the gear 60 may be pulled out of mesh with the gear 50 to declutch same for turning the needle or pointer 61b or setting it independently of the gear drive as will be explained hereinafter. The meter F is preferably enclosed in a cover or housing 63 which has a handle 63:: thereon. The face 63b of the meter F has a dial with graduations arranged in a generally circular form and running from zero on the left to in a clockwise direction. Preferably only about three-fourths of the circle is utilized for the graduations which are in portions of an inch, and the other onefourth provides for movement of the rod 10 relative to the finger 35 above the uppermost notch 30a without showing a reading on the meter F. Typically, with one hundred graduations on the scale, each small graduation would be representative of 0.0005 inches of stretch in the pipe or casing C.

In the use or operation of the apparatus of this invention, the free point indicator tool T is lowered inside the well pipe or casing C to determine the elevations at which such pipe is free and stuck. Normally, it is desired to locate the point at which the pipe C is stuck as indicated at C in FIG. 1, but prior to making measurements to locate the stuck point C, several measurements are required in the part of the pipe C which is known to be free to establish the average amount of stretch in the pipe C with a predetermined pull thereon. Thereafter, the tool T is lowered to an elevation which is believed to be in proximity to the stuck portion C and additional testing is conducted.

During the test at each elevation, after the lowering of the tool T has stopped, the operator first reads the odometer 65. Then, the flexible line L is raised until the shoulder 10c on the lower end of the control rod 10 engages the shoulder 22b on the lower end of the guide ring 22 which is at the sensing element of the apparatus. As the rod 10 is being pulled upwardly, the weight indicator indicates the weight on the line L due to the rod 10, jars, friction and all parts supported by the line L until the shoulder 10c engages the shoulder 22b. Then, an amount of pull is applied on the line L as indicated at the weight capacitor B which is in excess of the weight on the line L when moving the rod 10 upwardly in the tool T. With such weight being noted by the operator, the knob 61a is pulled outwardly so that the gear 60 is released from the gear 50 and the pointer 61b is turned so that it points to zero on the dial on the face of the meter F. In such position, the sections S and 5-1 are in the closed position with the shoulders 12b and 20d in contact with each other (FIG. 2B). In such closed position, the point 35a of the finger 35 is in contact with the control rod 10 as shown in FIG. 2A. In the closed position, the end 35d is in contact, or substantially in contact, with the stop surface 14b, and the spring 40 urges the finger 35 to pivot in a clockwise direction (as viewed in FIG. 2A), but it cannot do so even when the rod 10 has been moved upwardly to dispose the tapered section 10b at or above the finger point 35a because of the contact of the upper end 35d with the stop surface 14!).

The line L is lowered approximately the same amount as it was raised which can be done by lowering the line L until the odometer 65 reads the same, or slightly less than the first odometer reading taken when the tool T was lowered. As the line L is lowered, the meter pointer 61b is turned clockwise because of the movement of the line L over the measuring wheel M which is connected to the meter F, as explained. Since the Line L is stretched when pulling the rod 10 to its uppermost position due to the weight of line L, parts thereon, and friction, when the line L is lowered to the original reading on the odometer 65, that amount of stretch in the line L is relieved or slacked off. The extent of that stretch causes the pointer 61b to move accordingly. For example, assume that the line L stretched 5 feet when the rod 10 is pulled to its upper position, and the rod 10 has approximately a 7-foot travel, with 5 feet from the uppermost notch 30a to the lowermost notch 30b. Also, the graduations from to I00" on the meter correspond to the feet of travel from the lowermost notch 30b to the uppermost notch 30a, and the nongraduated part from 100" to zero corresponds with approximately the rest of the travel of the rod (about 2 feet). Under such conditions, upon lowering the line L,. the pointer 61b moves from zero clockwise to 100" as the stretch in the line L is relieved. Continued lowering of the line L causes the pointer 61b to continue its clockwise movement, with the movement from 100" to zero and back to 100 corresponding to the 7feet of travel of the control rod 10. Thereafter, the operator pulls upwardly on the line L again until the pointer 61b has moved counterclockwise back to zero. Then the stretch is again back in the line L and there is no weight on the tool T which might otherwise interfere with the stretching of the tool T later when the casing C is stretched.

If the amount of stretch is something different than the 5 feet assumed in the above example, and the other conditions are the same, then-the pointer 61b will of course point to some point other than the 100," more or less, but this is immaterial since the operator simply returns the pointer 61b to zero after the line L has reached the original reading on the odometer 65.

When the tool T is in the free part of the casing C, the line L is usually pulled up so that pointer 61b moves counterclockwise past zero to the unmarked area between zero and lOO." This is because when the pipe C is stretched, not only is the pipe stretched between the upper and lower friction means R and R-l, but also, the outer part of the tool T actually moves upwardly relative to the rod 10 an amount equal to the stretch in the casing C from the tool T to the stuck point C. This is also one reason for the square portion of the rod 10.

Thus, after the line L has been pulled upwardly to set the pointer 61b on zero or preferably between zero and 100," the operator applies a predetermined amount of pull on the casing C.

if the tool T is in a free portion of the pipe, there will be a stretch in the casing C between the upper and lower sections S and 5-1 of the tool T since the friction springs R and R-l will move with the casing C as it is stretched causing the sections S and 5-1 to move relative to each other. The upper section S moves upwardly relative to the lower section S-l to move the stop surface 14b upwardly relative to the finger 35.

With the tool T thus moved to an extended position due to the stretch in the casing C, the line L is pulled upwardly until the same reading is obtained on the weight indicator B as was previously obtained prior to the stretch in the casing C at the time the meter was set on 0. Such movement of the line L results in an upward movement of the rod 10. When the rod 10 moves upwardly enough so that the reverse tapered section 10b is opposite to or above the lower end 350 of the finger 35, the finger 35 can then pivot clockwise, the extent of which ultimately depends upon the extent to which the stop surface 14b has moved upwardly relative to the finger 35 during the can move upwardly until the lower end 35a of the finger 35 engages within one of the

notches

30a, 30b or 30c. In FIG. 8, the pointed end 35a is shown as being positioned in a notch 300 which is one of the intermediate notches between the uppermost notch 30a and the lowermost notch 30b. The particular notch in which the finger 35 is disposed will depend upon the extent of the inward pivoting of the lower pointed end 35a of the finger 35. Since the stepped notches on the notched plate 30 are on a taper or angle with respect to the central axis of the control rod 10, the greater the amount of stretch in the pipe or casing C, the greater the pivotal movement of the finger 35 and therefore the higher the notch engaged by the finger 35.

lt is to be noted that the readings on the meter F are taken after the same amount of weight is indicated on the weight indicator B as was indicated when the line L was pulled up wardly prior to placing any stretching force on the casing C. This assures that all forces such as friction, drag, and stretch of the line L are compensated for when the reading on the meter F is obtained. The indicator F reads in actual inches or other units of measurement of stretch of the casing C and such readings are preferably in thousandths of an inch.

Since the operator takes several readings on the meter F in the part of the casing C which heknows to be free to establish anaverage free point reading on the meter F, if the reading on the meter F is less than such average free point reading, then the operator knows the casing C is stuck or partially stuck at the point of the tool T.

Should the tool T be entirely in a stuck portion C' of the casing C there is no relative movement between the upper section S and the lower section 8-1 when a stretching force is applied to the casing C, and therefore, the control rod 10 moves upwardly for its full length to return to the position wherein the shoulder lflc engages the shoulder 22b. In such case, the indicator or pointer 6lb will be pointing to the graduation mark .0 on the meter F.

Where there has been some stretch in the pipe or casing C, but it is not the full amount of stretch obtained when the tool is in a free portion of the casing C above the stuck point C, the finger 35 will engage in either the lowermost notch 30b or one of the intermediate notches 30c between the lowermost notch 30b and the uppermost notch 30a so that the indicator or pointer 61b will read at some point between the graduations 0" and "100." For example, if the tool T is opened only half of its full amount when the casing C is stretched, the pointer 61 would point to a graduation mark which is less than the average free point reading so that by taking readings with the tool T at different elevations in the casing C, the operator can tell with reasonable accuracy the location of the stuck portion C of the pipe C.

The operator repeats the above-described method as necessary until he locates the stuck portion C where there is no stretch or substantially no stretch in the casing C.

It should be understood that the notched plates 30'may be integral with the control rod 10, or they may be formed in a single piece or in any other way so long as they provide the tapered or angled series of notches for engagement with the finger 35 in the manner heretofore explained.

lclaim:

1. An apparatus for determining the elevations of stuck and free portions of pipe in a well, comprising:

a. a free point indicator tool having:

1. an upper section and a lower section mounted for longitudinal movement relative to each other;

2. friction means on each of said sections for frictionally engaging the inside of a pipe to thereby cause said upper section to move upwardly relative to said lower section upon a stretching of the pipe;

3. stretch response means forming part of the tool for multiplyingthe amount of movement of said upper section relative to said lower section;

b. a wire line operably connected to said stretch response means and extending to the surface for movement at the surface in accordance with the movement of said stretch response means;

. a measuring wheel for measuring the amount of movement of said wire line;

d. a meter operably connected to said measuring wheel and calibrated to indicate the stretch in the pipe;

e. a finger pivotally mounted on one of said sections;

f. a stop surface on the other of said sections adapted to be engaged by said finger for controlling the extent of pivoting of said finger in accordance with the relative movement of said upper section relative to said lower section; and

g. a control rod movable longitudinally relative to said sections and said finger and having a surface adapted to be engaged by said finger for limiting the extent of longitudinal movement of said rod in proportion to the longitudinal movement of said upper section relative to said lower section.

2. The structure set forth in claim 1, wherein said surface on said control rod includes:

a. a plurality of longitudinally spaced notches disposed thereon at an angle to the central axis of said rod, with the lateral distance from the finger being least at the lowermost notch and the greatest at the uppermost notch.

3. The structure set forth in claim 1 wherein said surface on said control rod includes:

a. a plurality of longitudinally spaced notches disposed thereon at an angle to the central axis of said rod, with the lateral distance from the finger being least at the lowermost notch and the greatest at the uppermost notch;

b. said finger having a pointed end which is pivoted inwardly by coaction with said stop surface upon a stretching of the pipe to an extent corresponding to the stretch in the pipe for engaging in one of said notches upon an upward movement of said control rod relative to said finger to thereby stop further upward movement of said control rod relative to said finger and said sections.

4. The structure set forth in claim 1, including:

a. resilient means for applying a constant force urging said finger in a direction towards said stop surface and for movement relative thereto as permitted by the position of said stop surface.

5. A free point indicator tool, comprising:

a. an upper section and a lower section mounted for longitudinal movement relative to each other;

b. friction means on each of said sections for frictionally engaging the inside of a pipe to thereby cause said upper section to move upwardly relative to said lower section upon a stretching of the pipe;

c. a stretch response means forming part of the tool for multiplying the amount of movement of said upper section relative to said lower section; and

d. said stretch response means including:

1. a finger pivotally mounted on one of said sections;

2. a stop surface on the other of said sections adapted to be engaged by said finger for controlling the extent of pivoting of said finger in accordance with the movement of said upper section relative to said lower section;

. a control rod movable longitudinally relative to said sections and having a plurality of longitudinally spaced notches disposed thereon at an angle to the central axis of said rod for the engagement of said finger in one of said notches to limit the extent of longitudinal movement of said rod relative to said finger and said sections in proportion to the longitudinal movement of said upper section relative to said lower section.

6. The structure set forth in claim 5, including:

a. resilient means for applying a constant force urging said finger against said stop surface for effecting a pivoting of said finger upon a stretching of the pipe to an extent corresponding to the stretch in the pipe.

Claims

1. An apparatus for determining the elevations of stuck and free portions of pipe in a well, comprising: a. a free point indicator tool having: 1. an upper section and a lower section mounted for longitudinal movement relative to each other; 2. friction means on each of said sections for frictionally engaging the inside of a pipe to thereby cause said upper section to move upwardly relative to said lower section upon a stretching of the pipe; 3. stretch response means forming part of the tool for multiplying the amount of movement of said upper section relative to said lower section; b. a wire line operably connected to said stretch response means and extending to the surface for movement at the surface in accordance with the movement of said stretch response means; c. a measuring wheel for measuring the amount of movement of said wire line; d. a meter operably connected to said measuring wheel and calibrated to indicate the stretch in the pipe; e. a finger pivotally mounted on one of said sections; f. a stop surface on the other of said sections adapted to be engaged by said finger for controlling the extent of pivoting of said finger in accordance with the relative movement of said upper section relative to said lower section; and g. a control rod movable longitudinally relative to said sections and said finger and having a surface adapted to be engaged by said finger for limiting the extent of longitudinal movement of said rod in proportion to the longitudinal movement of said upper section relative to said lower section.

2. The structure set forth in claim 1, wherein said surface on said control rod includeS: a. a plurality of longitudinally spaced notches disposed thereon at an angle to the central axis of said rod, with the lateral distance from the finger being least at the lowermost notch and the greatest at the uppermost notch.

3. The structure set forth in claim 1, wherein said surface on said control rod includes: a. a plurality of longitudinally spaced notches disposed thereon at an angle to the central axis of said rod, with the lateral distance from the finger being least at the lowermost notch and the greatest at the uppermost notch; b. said finger having a pointed end which is pivoted inwardly by coaction with said stop surface upon a stretching of the pipe to an extent corresponding to the stretch in the pipe for engaging in one of said notches upon an upward movement of said control rod relative to said finger to thereby stop further upward movement of said control rod relative to said finger and said sections.

3. stretch response means forming part of the tool for multiplying the amount of movement of said upper section relative to said lower section; b. a wire line operably connected to said stretch response means and extending to the surface for movement at the surface in accordance with the movement of said stretch response means; c. a measuring wheel for measuring the amount of movement of said wire line; d. a meter operably connected to said measuring wheel and calibrated to indicate the stretch in the pipe; e. a finger pivotally mounted on one of said sections; f. a stop surface on the other of said sections adapted to be engaged by said finger for controlling the extent of pivoting of said finger in accordance with the relative movement of said upper section relative to said lower section; and g. a control rod movable longitudinally relative to said sections and said finger and having a surface adapted to be engaged by said finger for limiting the extent of longitudinal movement of said rod in proportion to the longitudinal movement of said upper section relative to said lower section.

3. a control rod movable longitudinally relative to said sections and having a plurality of longitudinally spaced notches disposed thereon at an angle to the central axis of said rod for the engagement of said finger in one of said notches to limit the extent of longitudinal movement of said rod relative to said finger and said sections in proportion to the longitudinal movement of said upper section relative to said lower section.

4. The structure set forth in claim 1, including: a. resilient means for applying a constant force urging said finger in a direction towards said stop surface and for movement relative thereto as permitted by the position of said stop surface.

5. A free point indicator tool, comprising: a. an upper section and a lower section mounted for longitudinal movement relative to each other; b. friction means on each of said sections for frictionally engaging the inside of a pipe to thereby cause said upper section to move upwardly relative to said lower section upon a stretching of the pipe; c. a stretch response means forming part of the tool for multiplying the amount of movement of said upper section relative to said lower section; and d. said stretch response means including:

6. The structure set forth in claim 5, including: a. resilient means for applying a constant force urging said finger against said stop surface for effecting a pivoting of said finger upon a stretching of the pipe to an extent corresponding to the stretch in the pipe.