US2275936A - Casing bridging device - Google Patents

Description

March 10, 1942. R, Q BAKER cAsING BRIDGING DEVICE Filed July 2, 1940 sueE/v C. BAKER) Patented Mar. 1.0, 1.942

UNITED STATE CASING BRIDGING DEVICE Reuben .0. Baker, Coalinga, Calif., assignor to Baker Oil Tools, Inc., Vernon, Calif., a eorporation of California Application Joly 2, 1940, serial 10,343,584

12 Claims.

This invention relates to devices employable in well bores, and is particularly directed to that type of device which is capable of forming an annular bridge or barrier between a well casing and wall of a conning bore hole. Devicesof this general character are disclosed in my prior Patents Nos. 1,561,768 and 2,117,538.

It is an object of the presentnnvention to provide an improved device for forming an annular bridge between a casing and wall of a confining bore hole, the device being held initially in extended, retracted position adjacent the casing while being lowered in the hole, release of the device allowing its contraction along the casing and expansion radially into contact with the wall of the hole.

Another object of the invention is to provide an annular casing bridge having a generally helical form when .in retracted position, and shaped generally as a conical spiral when expanded against the wall of a bore hole. It is preferred that the bridge inherently tend to assume the latter form.

A further object of the invention is to provide an initially retracted annular barrier capable of being released hydraulically to bridge the annular space between a supporting casing and the wall of a confining well bore.

This invention has otherpobjects that will become apparent from a consideration of the embodiment shown in the drawing accompanying and forming vpart of the present specification. This form will now be described in detail, but it is to be understood thgtfsuch detailed description is not to be taken in a limited sense, since the scope of the invention is best dened by the appended claims.

Referring to the drawing:

Figure 1 is an elevation of the casing and annular bridge device, partly in section, shown in retracted position for lowering in a well bore;

Figure 2 is a view similar to Figure 1, with the annular bridge in tripped condition expanded into engagement with the wall of a bore hole;

Figure 3 is a view similar to Figure 2, with the annular bridge in expanded position, illustrated as supporting an annular column vof cementitious material which has been ejected from the casing;

Figure 4 is a partial, longitudinal section taken generally along the line I-I in Figure 1; and

Figure 5 is a plan view of the bridge device in unrestrained condition.

As shown in the drawing, the annular bridge consists of a coil I of preferably iiat spring material inherently tending to assume a plane spiral 55 or conically spiral form when unrestrained (see Fig. 'Ihe lower end I Il of this spring is tixedly secured to the casing A, as by welding, and is coiled upwardly and helically therefrom -around 5 the casing, being held in retracted position snugly 4 against the casing itself, or` some intervening member, by suitably detachably securing its upper end I2 to the casing, as by a strap I3 welded to the casing. The upper end I2 of the spring 1o is rst passed through the strap and is` then crimped to prevent itsinadvertent withdrawal through the strap and .release of the annular bridging device.

Release of the crimped end I2 from the strap l5 I3 will permit the coil spring to contract downwardly along the casing and expand radially into contact with the wall of the well bore, or with any other coniining member. is action will occur since the coil spring Illv is initially wound as a plane spiral (see Fig. 5), and inherently tends to assume this normal shape or condition when unrestrained. Due to thepresence of the wall of the well bore, the released spring isl incapable of closing entirely to a true plane spiral form, but assumes the inverted conically spiral or frusto-conical shape shown in Figures 2 and 3. The annular bridge thus formed is capable of supporting material and preventing its passage between the casing and wall of the bore hole.

In the drawing, the particular bridging dev vice is disclosed inconjunction with a section of casing A especially designed for use in the depositing of cementitious material in the annulus around the casing above the bridge. Instead of initiauy retreating the bridge as a, helix directly against the casing, a rubber or other expansible or elastic sleeve I4 is provided within the confines of the spring I0. Thelower end I5 of this sleeve is secured to the casing-by any suitable means, as by helically winding a suicient number of turns of copper wire I6 around that end, which are then integrated by solder. The sleeve I4 extends upwardly from the wired portion adjacent the lower end II of the spring to a point immediately below thev strap I3 initially holding the crimped end I2 of the spring in position. -One or more ports Il are formed through the wall of the casing adjacent the upper end I8 of the rubber sleeve through which cement slurry I9 or other iiuid-like material can pass for ejection into the annular space between the casing and the wall of the conning bore. It is a parent that the sleeve I I initially closes the ports I1.

The device is assembled on the casing A in retracted position, as shown in Figure- 1, and is lowered to the desired position within the well bore. To release the retracted spring bridging device, the pumps are started at the surface of the casing and suicient pressure developed to expand the upper end I8 of the rubber sleeve I4 radially. .Such expansion will exert a longitudinal force along the last turn Ilia of the spring to pull its crimped end I2 through the strap I3 and release the helical bridging device. Removal of restraint; will permit the spring I `to assume its conically spiral position,` creating an annular barrier between the casing and the wall of the bore hole.

The ejection of the desired amount oi cement slurry I9 through the ports I1 will probably expand the sleeve I4 outwardly against the wall of the bore over a great portion of its length, the

weight of the cement slurry causing the lower portion of the sleeve to fold downwardly and rest upon the annular bridge I0. assisting the latter in forming a leak-proof barrier to the passage of the cement slurry downwardly past the bridging point. The rubber sleeve I l will probably assume the general shape shown in Figure 3, although it might assume some other conguration. In any event, it is provided mainly to close the ports I1 and enable the upper end I2 of the spring to be released hydraulically. Although the close fit between the coils of the spring will allow little if any leakage down past the bridging device, the rubber sleeve oiers further assurance against the occurrence of such leakage.

I claim:

1. In combination, a tubular well member, and an annular bridging device on said member comprising a spring adapted to .occupy a retracted position with respect to said member and an expanded position in engagement with the wall of a conilning bore hole, said spring having a coil form both while in retracted and expanded positions.

2. In combination, a tubular well member, a coil spring on said member, means for holding said spring in retracted position wound generally helically around said tubular member, and means for releasing said spring to enable it to assume a generally conical spiral form bridging the annular space between said member and a. confining bore hole. l

3. In combination, a well casing, a coil sprmg on said casing having one of its ends secured thereto, means detachably securing the other end of the spring to said casing, whereby said spring is held in retracted position wound generally helically around said casing, and means for releasing said other end of said spring to enable the spring to contract along the casing and assume a generally spiral form bridging the annular space between said casing and a conning bore hole.

4. In combination, a well casing, a coil spring on said casing having its lower end secured thereto, means detachably securing the upper end of the spring to the casing to hold the spring in retracted position wound generally in helical fashion around said casing, and hydraulically actuated means for releasing said upper end of said spring, permitting said spring to contract downwardly along the casing and assume a generally spiral form bridging the annular space between said casing and a conning bore hole.

5. In combination, a well casing, a coil spring on said casing having its lower end secured iixedly secured thereto and its other end detachmeans, and one or more ports in the casing for conducting uid into the sleeve to expand its upper end and release the upper end of the spring, permitting said spring to contract downwardly along the casing and assume a generally spiral form bridging the -annular space between lsaid casing and a coniining bore hole.

6. In combination, a well casing, a coil spring on said -casing having its lower end secured thereto, means detachably securing the upper end of the spring to the casing above one or more ports therethrough to hold the spring in retracted position wound generally helically around said casing, an elastic sleeve between the casing and helical spring normally closing said ports, said sleeve having its lower end iixed to the casing adjacent and above the lower end of said spring and its upper end terminating adjacent said detachable securing means, iiuid under pressure expanding the upper end of said sleeve to open said ports and release the upper end of the spring, permitting said spring to contract downwardly along the casing and assume a generally spiral form bridging the annular space between said casing and a conning bore hole.

'7. In combination, a ported well casing, an elastic sleeve on said casing normally closing said ports, a coil spring on said casing having one end ably secured thereto to hold the spring in retracted position wound generally helically around said sleeve and casing, release o'f said other end of said spring allowing it to contract along the casing free of said ports and assume a generally spiral form bridging the annular space between said casing and a coniining bore hole.

8. In combination, a well casing, a device on said casing for bridging the annular space between said casing and the wall of a conning well bore, means for initially holding said device in retracted position, and hydraulically actuated means comprising an expansible sleeve for releasing said holding means, enabling said device to bridge said annular space.

9. In combination, a well casing, a device on said casing for bridging the annular space between said casing and the wall of a confining well bore, means for initially holding said device in retracted position, and hydraulically actuated means comprising an expansible sleeve responsive to the pressure of fluid within said casing for releasing said holding means, enabling said device to bridge said annular space.

10. In combination, a well casing, a device held on said casing under strain for inherent outward expansion to bridge the annular space between said casing and the Wall of a confining bore hole, means for initially holding said device under such strain and in'retractecl position, and hydraulically actuated means externally of said casing for releasing said holding means, enabling said device to bridge said-annular space.

1l. In combination, a well casing, a spring device held on said casing under strain for inherent outward expansion to bridge the annular space. between said casing and the Wa'll of a conilning bore hole, means for initially holding said device under such strain and in retracted position, and hydraulically actuated means externally of said casing responsive to the pressure of iluid within said casing for releasing said holding means, enabling said device to bridge said annular space.

12. In combination, a well casing, an annular bridging device on said casing comprising a spring coiled generally co-axially of said casing,

means for holding said spring against said casing in retracted position, and means for releasing said coil. spring from said holding means to permit its expansion into engagement with the wall of a coniining well bore.

REUBEN C. BAKER.

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