US2665765A - Segmental slip subsurface well tool - Google Patents

Description

Jan. 12, 1954 R. c. BAKER 2,665,765

SEGMENTAL SLIP SUBSURFACE WELL TOOL.

Filed April 3, 1950 2 Sheets-Sheet l INVENTOR. REUBEN C BAKER,

197- TOR/VEYJ' Jan. 12, 1954 R c. BAKER 2,665,765

SEGMENTAL-SLIP SUBSURFACE WELL TOOL Filed April 5, 1950 2 Sheets-Sheet 2 INVENTOR. REUBEN C: BAKER,

fir TUBA/E75 Patented Jan. 12, 1954 SEGMENTAL SLIP SUBSURFACE WELL TOOL Reuben C. Baker, Coalinga, Calif., assignor t0 Baker Oil Tools, Inc., Vernon, Calif.,

ration of California a corpo- Application April 3, 1950, Serial N 0. 153,540

7 Claims. (01. 166-12) The present invention relates to subsurface well tools, and more particularly to well tools embodying segmental slips that are expandible outwardly against well casing, or similar conduits, disposed in well bores.

Subsurface well tools are used that include slips for anchoring them in well casing and the like. The slips are originally retained in retracted position and are later expanded outward- 1y into engagement with the well casing. The slips may not move outwardly in transverse alignment with each other, or they may not remain in transverse alignment after engaging the casing, which will place, or tend to place, the well tool off center within the casing, and result in its inability to perform properly its intended function or functions. Devices are known for maintaining the slips in transverse alignment, but they tend to urge them to a retracted position after they have been expanded against the casing, and may result in the failure of the slips to retain the well tool anchored to the casing.

Accordingly, an object of the present invention is to provide a subsurface well tool having slips that remain in transverse alignment at all times, and which imposes no retracting forces on the slips once they have been shifted against the well casing, or similar well conduit.

Another object of the invention is to provide subsurface well tools including slip aligners that can be installed easily in the slips, and which are comparatively inexpensive.

A further object of the invention is to provide subsurface well tools having slips and elements for retaining the slips in alignment, and in which the elements are capable of retaining themselves in appropriate position within the slips. T

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal view, partly in section and partly in elevation, of a well packer with its parts in retracted position;

III

Fig. 2 is a view similar to Fig. 1, with the well packer anchored in packed-off condition within a well casing;

Fig. 3 is a cross-section, on an enlarged scale, taken along the line 3-3 in Fig. 1, and disclosing the manner of installing the slip aligners in the slips;

Fig. 4 is a cross-section, on an enlarged scale, taken along the line 4-4 in Fig. 2;

Fig. 5 is an enlarged fragmentary section through part of the well tool, illustrating the manner of assembling the slip aligners within the slips;

Fig. 6 is a view similar to Fig. 5, disclosing a slip aligner inserted completely in place;

Fig. 7 is an isometric view of aligner elements.

The invention is disclosed in the drawings as applied to a well packer A of the general type disclosed in the United States Patent No. 2,121,051. This well packer is designed to be lowered through a Well casing B on the lower end of a tubular string C, with the packer parts in retracted position. The packer includes a one of the slip main body I 0 that can be secured to the lower end of the tubular string C by means of a suitable left-hand threaded connection II. This body carries a set of upper annular segmental tapered slips 1 2 adapted to be moved into engagement with the casing by an upper conical expander l3 that is initially secured to the body III by one or more shear screws M. The upper slips l2 are retained initially in retracted or ineffective position by shear screws l5 securing them to the conical expander [3, the upper ends of the slips engaging the upper surface of an abutment member or ring l6 threaded on the main body.

A lower set of annular segmental slips [1 is initially held in retracted position by attaching them to a lower conical expander l 8 through the agency of shear screws Hi. This lower expander is initially held in ineffective position by shear screws 20 threaded into the body. The lower ends of the lower slips engage an abutment consisting of a flanged portion 2| at the lower end of the body and a valve housing 22 threaded on this flange.

A packing sleeve 23 of synthetic or natural rubber is positioned on the body 10 between and suitably secured to the ends of the expanders l3, l8. This sleeve 23 is retained originally in retracted position free from contact with. the easing wall, but is capable of being expanded into engagement therewith.

It is to be noted that the coengaging surfaces on the upper conical expander I3 and upper slips I2 taper in an upward and inward direction, so that relative longitudinal movement of the upper expander within the slips I2 will move the latter outwardly against the casing B. In like manner, the lower expander I8 and lower slips I1 have their coengaging surfaces tapering in a downward and inward direction, in order that relative longitudinal movement of the lower expander within the slips I1 will shift them radially outward into engagement with the casing.

The valve housing 22 contains a tripping ball seat 24 that is initially held therewithin by a shear screw 25. This seat has an upstandin arm 26 for holding a'buoyant back pressure valve ball 21 in ineffective position against the interior of the housing, to prevent its upward movement and seating against a valve seat 28 at the lower end of the main packer body I0. Removal of this arm 26 by pumping the tripping ball seat unit 24 out of the housing permits the ball 21 to engage its cooperable seat 28 whenever reverse flow of fluids through the body I tends to occur.

The packer A is run in the casing to the desired setting point, after which a tripping ball 29 may be lowered or pumped down through the tubular string C into seating engagement with the tripping ball seat 24; Such engagement prevents any further downward passage of fluid through the well packer A, and allows the pressure of the fluid within the tubing string C and packer body I0 to be increased. This fluid under pressure passes outwardly through ports 30 that open through the body I0 into the interior of the packing 23. Fluid under pressure inflates and elongates the packing sleeve 23, and urges the upper expander I3 upwardly, disrupting the shear screws I4, I and shifting the upper expander I3 within the slips I2, sliding the latter radially outward along the abtument ring I6 and into engagement with the wall of the well casing B. The lower shear screws I9, have a substantially greater shear value than the upper screws I4, I5, which insures disruption of the latter under the action of the fluid pressure, as above described.

After the upper slips I2 have beenexpanded against the casing B, an upward strain may be taken on the tubing string C, which shifts the packer body It! upwardly within the upper cone l3, and carries the lower expander I8 and slips I1 upwardly with the body I0. This action foreshortens and compresses the packing sleeve 23 and expands it outwardly into sealing engagement with the wall of the well casing. A con tinuation of the upward strain then disrupts the lower shear screws I9, 20, which allows the lower abutment 2|, 22 to shift the lower slips I1 upwardly along the lower expander I8 and radially outward into anchoring engagement with the well casing B. All of the parts are held in the position to which they have been expanded, and are prevented from moving to retracted positions by a suitable lock ring 3 I, which may be in the form of a, split, contactile element contained within a groove 32 in the upper expander I3 and adapted to engage the downwardly facing annular ratchet teeth 33 formed on the exterior of the packer body I0, 7

After the packer A has been anchored against the well casing B, the pressure can be increased to shear the screw holding the tripping ball seat 24 to the valve housing 22, which enables the seat to be blown'o'ut of the valve housing and re"- moves the arm 26 from its holding position against the ball valve element 21, allowing the latter to shift upwardly into engagement with the valve seat 28, in the event that reverse flow through the well packer A tends to occur.

During the upward movement of the upper expander I3, the upper segmental slips I2 may not remain in transverse alignment, so as to insure their engagement with the well casing B in a manner to keep the upper expander I3 and packer body I0 centered or coaxial with respect to the axis of the casing B. One slip segment may drop downwardly along the upper expander a greater distance than another slip segment, which action would tend to place the upper expander I3 and body Ill off center. Were this to occur, the taking of the substantial upward strain on the tubing string C and body I0 necessary to expand the packing 23 and the lower slips I1 against the casing, and to fully and solidly anchor the well packer A against the casing, might impose a bending strain on the packer body III (which is usually a casting) and result in its failure. v

Even if the slips I2 are moved outwardly along the upper abutment I6 into engagement with the well casing B, while the packing sleeve 23 has been ballooned outward and elongated, as described above, the subsequent relieving of the pressure within the packer body IO and tubular string 0 would result in the contraction of the packing sleeve 23 and lowering of the upper ex pander I3 along the body. When this occurs, the slips I2 may not drop downwardly with the ex pander uniformly, one slip being lower than the other. Here again, the net result would be the wedging of the upper expander I3 and packet body -I 0 off center of the well casing, which might result in failure of the tool, or at least a potential improper packing oiT of the packing-23 against the casing, when the upward strain is taken on the tubing string C and packer body Ill. The aforenoted diiliculties are overcome by providing slip aligners 35 between the adjacent slips I2 of the upper set. These slip aligners consist of relatively wide V'-shaped elements made of sheet metal, such as spring brass, that is somewhat malleable. Each slip aligner 35 is relativelyshort in length and is adapted'to be inserted in a circumferential groove 36a formed jointly in all of the segmental slips I2, and in transverse alignment with each other, or "at right angles to the axis of the packer body ID. The slip aligner extends from one slip I2 across to the adjacent slip, bridging the gap 36 therebe tween. Originally, the slip aligner is relatively wide and generally V-shaped in cross-section, the distance across its side flanges or arms 31 being substantially greater than the width of the oncumferential groove 36a. The 'slipalig'n'er 35 is forced into the circumferential groove 36a, the side walls 38 of the latter moving the side flanges 31 toward each other.

One manner of installing a slip aligne'r is mus trated somewhat diagrammatically in Figs. 3, '5 and 6. As shown in Fig. 5, a slip aligne'r 35,- which may at first be straight, is placed with-its mid-portion across the gap 36 between adjacent segments I2. A hammer H may then be used to tap or start the aligner 35 into the circumferential groove 33a, which action moves the arms 31 of the element toward each other under the closing force exerted by the sides 38 of the circumferential groove. After the element has been started in the groove, a setting toolT maybe used, in the form of a relatively thin blade new; ing a concaveo'r arcuate end R, conforming gen= erally to the curvature of the base of the circumferential groove 3 6a. This tool is placed within the slip aligner 35 and its outer end struck with a hammer, forcing the slip aligner well within the groove 36a and also bending it into a generally arcuate shape, such as disclosed in Figs. 3 and 4-.

All of the slip aligners 35 may be mounted within the upper slips I2 in the manner described, each aligner extending within the circumferential groove 36a from one slip segment I2, across the clearance gap 36, into the next slip segment I2.

When the upper slips I2 are expanded outwardly against the Well casing as a result of upward movement of the upper expander I3 along the packer body III, the slip aligner elements 35 maintain the slips in transverse alignment with each other, but they do not offer any substantial resistance to radial outward movement of the segments I2. Of course, as the segments are urged outwardly by the conical expander, the gaps 36 between the adjacent segments widen. However, the slip aligners 35 are long enough to each bridge the larger gap after the slips have been fully expanded into anchoring engagement with the well casing. In the event that the conical expander I3 tends to shift downwardly as a result of bleeding oif of the pressure within the tool, the slip segments I2 will merely move downwardly along the casing as a unit with the cone I3, the aligning elements 35 maintaining the segments in transverse alignment with one another. As a result, it is evident that one slip cannot drop below another slip, so as to force the well tool off center.

It is also to be noted that the slip aligners 35 are independent of one another, and, accordingly, do not impose any inwardly directed forces tending to shift the segments I2 inwardly toward retracted position, particularly during downward movement of the upper expander I3 along the packer body. The slips l2 will remain outwardly to the extent that they have been moved by the upper expander I3. As a result, when the tubing string C and packer body are moved upwardly. to expand the packing sleeve 23 and the lower slips I1 against the casing B, the upper slips I2 are in engagement with the well casing, and will instantly grip the casing more securely, to enable the aforementioned expanding actions of the other packer parts to take place. If the slips I2 were to retract, even slightly, from the well casing, they could not provide the necessary anchor against which the upward strain is taken, and it would be impossible to set the lower slips I1 and expand the packing sleeve 23 against the casing.

In view of the relative malleability of the aligner elements 35, which may be made of spring-like half-hard brass, for example, they can be made to conform generally to the curvature of the base of the circumferential groove 36a. Despite such curving or bending of the slip aligners, they still possess spring characteristics, in that the forcing of the elements within the circumferential groove 36a will cause the side flanges 37 to tend to spring apart, and grip or dig into the side walls 38 of the circumferential groove, thereby insuring retention of the aligners 35 in their appropriate position within the circumferential groove. The aligners will remain in position during outward expansion of the segments I2 against the casing, the slip segments and aligners merely sliding circumferentially with respect to one another without the aligners 35 tending to move outwardly of the'circumferential groove 36a.

The inventor claims:

1. A well tool, including a body adapted to be lowered in a well casing on a running-in string, means for anchoring said body to the well casing comprising a set of segmental slips having a circumferential groove therein, individual elements in said groove separate from each other for maintaining said slips in transverse alignment with respect to each other, each element extending from one segmental slip to an adjacent segmental slip and being at least as wide as the distance between the opposed side walls of the groove so as to be held in position by simultaneously frictionally engaging both of the opposed side walls of said groove.

2. A Well tool, including a body adapted to be lowered in a well casing on a running-in string, means for anchoring said body to the well casing comprising a set of segmental slips having a circumferential groove therein, individual elements in said groove separate from each other for maintaining said slips in transverse alignment with respect to each other, each element extending from one segmental slip to an adjacent segmental slip, and each element being generally V-shaped in cross-section and having spring-like side flanges pressing against the side walls of said groove to hold said element in position within said groove.

3. A well tool, including a body adapted to be lowered in a well casing on a running-in string, means for anchoring said body to the well casing comprising a set of segmental slips having a circumferential groove therein, individual elements in said groove separate from each other for maintaining said slips in transverse alignment with respect to each other, each element extending from one segmental slip to an adjacent segmental slip, each element being of springlike, malleable material and of generally arcuate shape and being at least as Wide as the distance between the opposed side walls of the groove so as to simultaneously frictionally engage both of the opposed side walls of said groove to hold said element in position within said groove.

4. A well tool, including a body adapted to be lowered in a well casing on a running-in string, means for anchoring said body to the well casing comprising a set of segmental slips having a circumferential groove therein, individual elements in said groove separate from each other for maintaining said slips in transverse alignment with respect to each other, each element extending from one segmental slip to an adjacent segmental slip, each element being made of springlike malleable material and being arcuate along its length and generally V-shaped in cross-section to provide side flanges of said element tending to move inherently apart into firm engagement with the side walls of said groove to hold said element in position within said groove.

5. A well tool, including a body adapted to be lowered in a well casing on a running-in string, means for anchoring said body to the well casing comprising a set of segmental slips having a circumferential groove therein, individual elements in said groove separate from each other for maintaining said slips in transverse alignment with each other, each element extending from one segmental slip to an adjacent segmental. slip, each element having opposed gripping portions simultaneously engaging both of the opposed side walls 1 of said groove to retain said element in said groove.

6. A well tool, including a body adapted to be lowered in a Well casing on a running-in string, means for anchoring said body to the well casing comprising a set of segmental slips having a cir- --cumferential groove therein, individual elements 'in said groove separate from each other for maintaining said slips in transverse alignment with respect to each other, each element extending from one segmental slip to an adjacent segmental slip, and each element having spring-like 'si'de portions simultaneously pressing against the side Walls of said groove to hold said element in position Within said groove.

7. A well tool, including a body adapted to be lowered in a well casing on a running-in string, means for anchoring said body to the well casing comprising a set of segmental slips having a 'cireumferential groove therein, individual elements REUBEN o. BAKER.

References Cited in the file of this patent UNITED STATES PATENTS Number 7 Name Date I 1,524,288 Burns Jan. 27, 1925 2,248,211 Young July 8, 1941 2,368,409 Burt Jan. 30, I945

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