US2822876A - Deep well bridge - Google Patents

Description

Feb. 11, 1958 w. R. MURROW ETAL DEEP WELL BRIDGE Filed Oct. 26-, 1955 11v moms DEEP WELL BRIDGE William R. Murrow, Independence, Kans., and Alpheus L. Connally, Efiingham, lll., assignors to The M & M Manufacturing Company, Independence, Kans., a corporation of Kansas Application October 26, 1955, Serial No. 542,856 7 Claims. (Cl. 166-192) The invention relates to deep wells common in oil fields and more particularly to a device for effecting a bridge in the well at any desired point in its height to serve as a plug or to facilitate pumping from a part of the well spaced above the bottom of the well.

One of the objects of the invention is to provide a light weight, inexpensive bridge which may be lowered into the well without likelihood of the bridge being caught as it is being lowered.

Another object is to provide a bridge which may be readily destroyed by a drilling tool after its usefulness has been terminated and it is desired to pump the well from a lower level.

Another object is to utilize a bridging device which will freely drain fluid from above the device when it is first installed and before the bridge is completed by the dumping of concrete, sand, or the like on the bridge device.

These general objects and other detail objects as will appear from the following description are attained 'by the structure illustrated in the accompanying drawings, in which:

Figure l is a section through spaced portions of a deep well illustrating some of the conditions encountered in the use of the bridge device and showing the device in dilferent positions ash is being pushed or thrust down the casing and through a window, which is an open sec- :tion in the casing, by the weight of the drill stem, or the like, to the desired position.

Figure 2 is in part a side elevation and in part a longitudinal section through the bridge device showing it applied to the lower end of a drill stem or the like.

Figure 3 is a transverse horizontal section on the line 33 of Figure 2.

The bridge device comprises an elongated tubular central frame or body 1. A series of fingers 3 of spring material have their lower ends secured to frame 1 and extend upwardly and outwardly therefrom and have upwardly pointed terminals 5 adapted to dig into rock or shale formation of a well, or the casing of a well, or the threads or collars of the casing to resist upward movement of the device from its desired position in the well.

A series of ribs 7 of spring material are secured at their lower ends to the central frame 1 at a point substantially higher than fingers 3 and extend outwardly and upwardly above the level of fingers 3 and form a support- :ing cage for a web member 9 of canvas or similar flexible material, the upper edge of which is folded over as indicated at 11 and gripped between return bend portions .13 of ribs 7, which hold the upper edge of the web taut when the ribs spread out and protect the upper edge of the web from being chafed or torn by frictional contact with the sides of the well as the device is thrust down "the casing, etc.

An adapter or mounting piece 15 has a threaded tapered upper portion 17 for engagement with the lower end of a 'rigid suspension member, such as a drill stem, or jars, or the like.

The piece 15 has a downwardly facing shoulder 21 for tes Patent 0 seating the upper end of frame 1. A reduced diameter portion 23 of piece 15 extends downwardly into frame 1, thereby providing perfect alignment of the bridge, or device, with the drill stem and the well. A series of wire springs 25 are secured to the inner upper portion of frame 1 and project downwardly and towards the axis of the frame and have their lower ends 27 bent outwardly to engage the inner wall of the frame. Springs 25 yieldingly engage the lower portion 23 of piece 15 and frictionally retain the bridge and portion 23 assembled during the insertion of the bridge into the well, but readily release the bridge from the mounting piece 15 when the drill stem 19 is raised and points 5 engage the rock or shale formation of the well or a ridge or other irregularity in the casing of the well.

The yielding fingers 3 and ribs 7 adapt the bridge for insertion in different sizes of casings and the fingers and ribs may spread outwardly beyond the diameter of the casing to engage the shale or rock formation surrounding the casingwhich is is being used in a well in which a window section of the casing has been eaten away by acid or removed by mechanical means. thereby permitting the forming of a bridge in the casing, above or below this window, or in the rock formation of the well, upon which an explosive charge may be placed and exploded, or the section from which the casing has been removed may be treated by other oil or gas field practices, such as perforating, fracturing or acidizing, or any combination of the above.

The vertical spacing of fingers 3 and ribs 7 (which elements serve as upper and lower guides for the bridge structure and the lower end of the rigid suspension member), together with the centering of the upper end of the device on mounting piece 15 insures the lateral stability of the device as it is lowered into the well so that, when the device is released by the removal of the drill stem, it will be positioned as shown in Figure 1 to provide a baffle which will engage concrete, rock, etc. applied to web 9. The alignment-maintaining feature prevents the bridging device being inclined to the well axis so as to be deflected out and into the open window section irrespective of the vertical and transverse extent. of the latter.

A downwardly pointed conical guide member 29 is secured to the lower end of frame 1 and facilitates the movement of the frame through fluid or loose material in the well under the thrust of the drill stem. The lower portion of frame 1 and of member 29 is apertured at 31 to drain fluid which may gather within the body prior to the completion of the bridge structure and thus avoid the building up of a column of fluid of sufiicient weight to push the bridge down further than desired before the concrete, sand, etc. has been introduced into the well.

With the device described above, any drilling crew can set a bridge without requiring outside help and special equipment other than the usual drill stem. When use of the bridge is finished, the light sheet metal and fabric device may be drilled out readily for further operations at a lower level in contrast to the resistance afforded by heavy cast iron structures in general use for similar purposes.

The details of the device may be varied without departing from the spirit of the invention and the exclusive use of those modifications coming within the scope of the claims is contemplated.

What is claimed is:

1. A deep well bridge structure adapted to be releasably attached to the lower end of an elongate rigid suspension member for lowering into a well borehole, said structure comprising a body, a circular series of spring-like fingers having their lower ends fixed to the exterior of the lower Patented Feb. 11, 1958 particularly desirable if the device 3, r portion of saidbody andproecting upwardly and outwardly-therefrom, a ci-rcular series'of cantilever spring ribs axially spaced above said fingers, said ribs having their lower ends fixed to said body, and the upper ends thereof projecting outwardly from the body, said andfi'ngers being ofa-length whereby in an unstressed condition the "upper endsiherebt describe peripheries of the borehole after detachmentof' said structure "from said suspension member, andquiclc-detachable rneans'for maintaining-saidbody andsaidisnspension member ina rigid coaxiat relationship before release said structure by said suspension member. 1

2. A deep'well bridgejstructure as setforth'in' claim 1 which-further includes-aweb of'fiexible material secured to-said ribs forretaining liquidconcrete and the like.

3; A deep well bridge structure as set forth in claim 2 in which the fingers :havetheir outer upper ends pointed to engage the sidesof theborehole-and hold the bridge against upward-movement in the well, and the ribs form acage for supporting the web ofiflexible material.

4. A deep well bridge structure as set forthin claim 2 in which the body-projects below thelower ends of said fingers and is providedwithadownwardly pointed cuplike terminal for guidingand centeringthe bridge as it is lowered into 'a well.

5. A deep well bridge structure as set forth in claim 2 in which the end portions of'the ribs are bent inwardly and downwardly and clamped over the edge of the web to sustain the same in spread-open position and to protect said edge against frictional contact with the sides of the borehole.

6. A deep well bridge structure as set forth in claim 2 n in which the body is-an elongated sheet metal tube and is provided with a downwardly pointed conical cup at its lower. endjsaid cup and-the lower portion of said tubehaving small apertures to drain :fiuid therefrom.

7. A deep well bridge structure asset forth in claim 6 wherein the lower end of said suspension member is of smaller. diameter thanthe inner periphery'of. the upper portion of said tube and wherein said means for maintaining said body andsa'id susepnsion'member in a rigid coaxial relationship comprises a plurality of elongated springs projecting inwardly of said tube and each fixed at one endto the upper-portion of said tube whereby said springs-frictionally retain the lower end of said suspensionrnember in assembled-relationship with said tube.

References Cited in the file of this patent UNITED STATES PATENTS

Images