US3195645A - Packer back-up ring structure - Google Patents

Description

July 20, 1965 G. n.. Looms PACKER BACK-UP RING STRUCTURE Filed Feb. 2, 1962 GLENN L. LOOHIS ATTORNE' United States Patent O 3395.645 PACKER BACK-UP RENE STRUCTURE Glenn L. Loomis, lasaflena, Tex.; dean Doyle `Loomis, ertecutrix of Glenn L Loomis, deceased, assigner to lean Doyle Loomis Filed lich. 2, i962, Ser. No, 176,537 3 Claims. (El. lod-203) The present invention relates -to a packing structure for use in forming a vseal between a rod-like element and a surrounding Wall of a well pipe and, more particularly, to a packing structure incorporating an improved packer back-up ring for preventing cold and flow of a packer when the packer is set against the Wall of a well pipe and then subjected to high pressures.

The packing structure of the present invention is preferably intended for use in a device for testing well pipe or the like for leaks, but it may also be used with other well equipment when it is desired to set a packer in the well pipe and the packer is subsequently subjected to extreme pressures. A typical testing device for which the packing structure of the present invention is preferably used is disclosed in my copending United States application serially numbered l70,711 and entitled Testing Tool for Nell Pipe or the Like and led concurrently herewith. The subject matter o the testing tool disclosed in the aforementioned copending application is incorporated by reference herein for that purpose.

In recent years, the flow tubing for oil or gas wells or the like has been made with an internal plastic lining. T he plastic lining which is usually coated on the interior of the pipe provides protection to the etal pipe from the corrosive action caused by acids and other iiuids flowed therethrough. The plastic lining of the sections of pipe is quite fragile and may be easily damaged if contacted by a well tool having a harder surface than the lining. in my aforementioned copending application, there is disclosed completely a well tool suitably coated on its exterior surfaces with a material as soft as or softer than the lining so as to protect the lining as the well tool is inserted into the pipe.

The back-up rings heretofore used in association with resilient packers to prevent cold ow of the packer under extreme pressure conditions have been made from arcuate metallic segments which were simultaneously expanded into engagement with the Wall or the pipe when the packer was expanded. Such a back-up ring is disclosed in my copending application Serial Number 754,197, tiled August ll, 1958, and entitled Tester Apparatus for Gil Wells or the Like and now United States Patent No. 3,038,542 issued June 12, 1962. lt has been found that the engagement of the metallic segments of the expansible segmental back-up ring with the plastic lining when the same are expanded by the annular pressure exerted by the packer immediately crushes the lining in the pipe and thus, when the well tool is removed, the eilectiveness oi the lining has been materially reduced as the pipe can be subjected to corrosive action at this point.

An important object of tne present invention is to provide a packer back-up ring structure utilizing an expansible segmental ring made of arcuate metallic segments, the expansion ofthe ring being controlled 4to prevent the Walls of the segments from engaging and crushing the lining in a plastic lined pipe.

Another object of the present invention is to provide a packing structure having an expansible segmental packer back-up ring associated therewith in which the segments of the ring are generally expanded radially outwardly a predetermined distance whereby the metallic segments do not engage the lining of a plastic lined pipe but still provide an eiiective block to the cold liow of the packer.

ld Patented duly 20, 1965 ICC Still another object of the present invention is to provide an expansible segmental packer back-up ring structure comprising metallic arcuate segments, the back-up ring structure including means to positively limit the amount of radial movement of the segment-s of the ring.

Since it is desirable to provide well tools with greater clearance from the walls of a plastic lined pipe so that the tools can be inserted into the pipe with less danger ot contacting the lining, the annular clearance necessary for expanding the back-up ring in order to prevent ilow ot the packer is increased. In view of this, it is a further obiect of the present invention to provide an expansible segmental back-up ring capable of being expanded over an annular distance greater than heretofore realized and then returned to its original retracted position.

These and other objects of the present invention will appear more fully in the following specification, claims and drawings in which:

FIGURE 1 is an exploded perspective View of a packer back-up ring structure of the present invention, one of the segments of the segmental ring being omitted for the purpose of clarity and the retainer band being shown partly in section; i

FlGURE 2 is a vertical section on a reduced scale and partly in elevation, the view illustrating the packing structure of the present invention as applied to a testing device;

FlGURE 3 is an enlarged fragmentary sectional view through a portion of one segment of the expansible segmental back-up ring of the present invention and illustrating tie same in a retracted position;

FlGUlE 4 is a view similar to FIGURE 3 but illustrating the position of the segment after the back-up Iring has been expanded; and

FEGURE 5 is an exploded perspective view similar to FlGURE 1 but illustrating a modiiied form of expansiblc back-up ring structure of the present invention.

Referring now to the drawings wherein like character and reference numerals represent like or similar parts, the packer back-up ring structure of the present invention is best shown in FGURE 2 utilized on the lower end of a testing device generally designated by the numeral 10. The testing device il? is of the type disclosed in my aforementioned applications -and generally includes an elongated tester body having spaced packers mounted thereon and `adapted to be expanded into engagement with the Walls of a well pipe 12 or the like. Suitable tiuid passages are provided in the testing device lil for supplying hydraulic iiuid under pressure to pistons acting against the packers, the pistons compressing the packers longitudinally and thu-s expanding them transversely so that they form sealing engagement with the well pipe 12 to define a sealed oli section of Well pipe to be tested.

The testing tool lil is also provided with suitable pressure responsive valves which permit the application of the hydraulic fluid under pressure to the sealed oil space between the packers in order to accomplish the test of the well pipe. A joint or connection between two sections of well pipe or the Well pipe wall itself may be tested by such a pressure method. After the well pipe has been tested, the pressure on the hydraulic fluid in the testing tool lil is relieved and the packers are relaxed so that the testing tool may be moved to a ditlerent position in the Well pipe to provide for a subsequent test, The testing procedure briey described above is disclosed in detail in my aforementioned pending lapplication entitled Testing Tool for Well Pipe or the Like as well as in my prior United States Patent No. 2,731,827, issued lanuary 24, 1956.

Referring now in detail to FIGURES 1 through 4, inelusive, the well pipe l2 is of lthe type having a protective lining C made ot a plastic material such as an epoxy resin or'the like. The packing structure of the present invention generally designated by the numeral 14 is carried on the elongated body ofthe testing device 1t) which may be considered for the purposes of this description as a rod-like element 16. Packing structure 14 includes a substantially cylindrical resilient packer l made of an elastomeric material such asrubber, synthetic rubportion 24 and the end of the packer 13 opposite the end nose end 24 and the back-up f abutting piston 2l). It will now be understood that when the piston 2) is extended or moved downwardly as viewed in FIGURE 2 Itoward the packer V155, it will cause the packer to compress longitudinally against the back-up ring structure 22 and expand transversely into sealing engagement with the wall of the flow tubing or well pipe 12.

Since the resilient packer 13 is made of an elastomeric material, it will not damage the plastic lining C of the pipe when it engages the same. As shown in FIGURE 2, the exposed por-tions of the testing device 10 including the piston 2d and the rod-like element 16 with its abutment portion 24tare coated with a non-metallic material M softer than the plastic lining C of the pipe. This feature 'of the well tool is disclosed `in detail in my laforementioned application entitled Testing Tool for Well Pipe or 4the Like. y Y The back-up ring structure 22 includes an expansible segmental back-up ring 26 positioned intermediate a pair of annular ringl elements 28 and Sil. The expansible segmental ring 26 is comprised of a plurality of arcuate metallic segments 32 having a curved outer peripheral surface 34. Each segment 32 is provided with a groove 36 in its outer peripheral surface, the grooves 36 of the segments deining a continuous groove when the segments are positioned together as a ring. The grooves 36 of the segments are adapted to receive an endless retainer band 38 made of a resilient elastomeric material such as rubber, synthetic rubber or lthe like. The retainer band 38 maintains the segments 32 of the ring unit position but also permits the segments to be expanded substantially radially outwardly of the longitudinal axis of the rod-like element 16. While the metallic segments 32disclosed herein are simple arcuate segments which abut each otheronV their radial faces,:the segments could be made to overlap one another in lthe Vmanner taught in my United States Patent No. 3,038,542 without departing from the spirit of the present invention.

In order to cause the segmental back-up ring 26 to uniformly expand and retract ina radial direction, the ends of each of the segments 32 are provided with iuwardly double-tapered surfaces 4t) and 42 separated by Y an outwardly facing step surface or abutment 44 therebetween. When the segments 32 are assembled as a unit and maintained in retracted position by the retaining band 3S, the double tapered surfaces 40 and 42 of the segments define inverted double cone ends. Each of the annular rings 23 and 3) are provided with double cone surfaces 46 :and 48 separated by an inwardly facing step surface or abutment Sd. As will now be apparent, the rings 2e and 3% cooperate with the oppositerends of the segmental back-up ring 26. Each of the rings 28 and 3) are provided with a center aperture 5G so that they may slide on the rod-like element 16.

When the packing structure 14 lis assembled on the rod-like element 16, as shown in FIGURE 2, theV lower Y ring Sit abuts the abutment portion 24 of rod-like element 16 and thus is prevented from moving longitudinally outwardly of the rod-like element 16, whereas the upper Y ring 2S abuts the end of packer 18 opposite the end which abuts the piston Ztl. Referring now to FIGURE 3, it Will 26 in a retracted be noted that when the segments 32 of ring 26 are in a retracted position, the surface 44 is spaced from the surface 5@ of ring 2S. As ring 23 moves toward ring 3), when the piston Ztl is extended, the inclined surfaces t6 and t8 of the rings 2S and 30 cooperate with the inclined surfaces d@ and l2 of the segments to cause the segments to wedge apart and move radially with respect to the longitudinal axis of the segmental ring 26. The segments 32 will continue to move ou-twardly until the outwardly facing surfaces 44V engage the inwardly facing surfaces 5t? of the rings 2S and 3d respectively. This limits further outward movement of the me-tallic segments 32 just short of the plastic lining C on the wall of the pipe 12 and thus protects the lining from being crushed. While the segmental ringd does not engage the wall of the well pipe 12, there is such a small clearance between the segments and the wall( that the back-up ring effectively blocks any tendency of the Vpacker 18 to flow when the packer is subjected to subsequent extreme pressures.

Y Referring now to FIGURE 5, a slightly modified form of back-up ring structure 22 is disclosed. In this ernbodiment of the invention, the arcuate segments 32 of the segmental ring 26 are provided with inwardly tapered ends 4d so that when they are assembled as a unit, the surfaces eil defined by the ends of the segments are an inverted cone. The rings 2S and 3% are provided with a complementary cone `surface 46', and it will be understood that when the ring 28 is moved toward the ring 30 Vpipe l2.

the surfaces 4d wedge against the surfaces ttl and cause the segments 32 to move radially outwardly.

In order to provide a stop for the metallic segments 32 so that they will not engage the lining of the well pipe 12, the elastomeric retaining band 38 has a greater radial thickness than the depth defined by the grooves 36' in the peripheral surfaces of the arcuate segments 32. By

\ such an arrangement, the outer peripheral surface of the resilientretaining band .'lf is spaced outwardly from the outer peripheral surface 34 of the segments 32. When the rings 28 and V36 are moved relatively toward one another, the segments 32 of the segmental ring 26 Vexpand radially until such time thatrthe outer surface of the retaining band 38 engages the plastic lining C of Since the band 38' is as soft orsofter than the lining of the well pipe 12, there is no damage to the lining upon Contact by the band 38. In effect, the band 3S engages the well pipe wall and provides a stop to prevent the segments from moving radially outwardly into engagment Ywith the well pipe.

By utilizing an endless retainer handmade of an elastomeric Vmaterial such as rubber, synthetic rubber or the like, in both of the environments of the present invention shown, a vgreater radial expansion of the segmental backup ring can be obtained. In Ythe past, coil springs and snap rings have been utilized tor retain arcuate segments of a segmental back-up ring inV position, but such prior `springs or snap rings do not have suicient elasticity or ability to maintain the segments in a relative position to one another as they are being expanded.

While the invention has Vbeen primarily disclosed in relation to its preferred use with a packing structure of a tester tool for oil and gas well flow tubing, it is, of course, within the Vscope of the present Vinvention that the improved packing structure could be used in ow tubing orV or the like: asubstantially cylindrically-shaped resiient packer mounted on the rod-like element; a pair of annular ring elements carried on said rod-like element and each aisance having a cone shaped surface on one end thereof, one of said ring elements abutting an end of said packer; an expansible segmental back-up ring carried on the rod-like element and having inverted cone shaped surfaces on each end thereof, said segmental back-up ring being interposed between said pair of annular ring elements with the cone surface of each annular ring element abutting respectively the inverted cone surfaces of said segmental back-up ring, said segmental back-up ring including a plurality of metallic segments; resilient means circumscribing said segmental back-up ring for maintaining the segments in a retracted position as a unit; means abutting the other of said ring elements and maintaining the same stationary with respect to said one ring element; means engaging said packer on the end opposite to the end engaging said one ring element for compressing said packer longitudinally and expanding the same transversely while also causing said annular ring elements to move toward one another to radially expand said segmental back-up ring; and means on each of said annular ring elements and on each end of said expansible segmental back-up ring for limiting radial expansion of the same to a predetermined amount.

2. In a packing structure for forming a seal between a rod-like element and a surrounding wall of a well pipe or the like: a substantially cylindrically-shaped resilient packer mounted on the rod-like element; a pair of annular ring elements carried on said rod-like element and each having a cone shaped surface on one end thereof, one of said ring elements abutting an end of said packer; an expansible segmental back-up ring carried on the rodlike element and having inverted cone shaped surfaces on each end thereof, said segmental back-up ring being interposed between said pair of annular ring elements with the cone surface of each annular ring element abutting respectively the inverted cone surface of said segmental back-up ring, said segmental back-up ring including a plurality of metallic segments; resilient means circumscribing said segmental back-up ring for maintaining the segments in a retracted position as a unit; means abutting the other of said ring elements and maintaining the same stationary with respect to said one ring element; means engaging said packer on the end opposite to the end engaging said one ring element for compressing said packer longitudinally and expanding the same Itransversely while also causing said annular ring elements to move toward one another and to radially expand said segmental ring and means on said annular ring elements and said expansible back-up ring for limiting radial expansion of the same to a predetermined amount, said last-mentioned means including an annular ridge on each of said ring elements, each ridge defining an inwardly facing surface, and said expansible segmental back-up ring having an annular ridge on each of its ends defined by projections on the ends of its segments, the annular ridges on the ends of said segmental back-up ring having outwardly facing surfaces spaced from the inwardly facing surfaces of the respective ridges of said annular rings when said back-up ring is in the retracted position.

3. In a packing structure for forming a seal between a rod-like element and a surrounding wall of a well pipe or the like: a substantially cylindrically-shaped resilient packer mounted on the rod-like element; a pair of annular ring elements carried on said rod-like element, one of said ring elements abutting an end of said packer, each of said ring elements having opposed surfaces which are double cone shaped and define an inwardly facing step surface; an expansible segmental back-up ring carried on the rod-like element and interposed between said pair of annular ring elements, said segmental back-up ring including a plurality of metallic segments, said segmental backup ring having opposite ends which are each inverted double cone shaped defining an outwardly facing step surface for cooperating respectively with respective inwardly facing step surfaces of said annular ring elements; resilient means circumscribing said segmental back-up ring for maintaining the segments in a retracted position as a unit with the step surfaces in the ends thereof spaced from the step surfaces of the respective annular rings; means abutting the other of said annular ring elements and maintaining the same stationary with respect to said one ring element; and means engaging said packer on the end opposite to the end engaging said one ring element for compressing said packer longitudinally and expanding the same transversely while also causing said annular ring elements to move toward one another to radially expand said segmental back-up ring until the outwardly facing step surfaces on the ends of the said back-up ring abut the respective inwardly facing step surfaces on the annular rings.

References Cited by the Examiner UNITED STATES PATENTS 705,059 7/02 Flynn 138-90 XR 922,544 5/09 Turner et al. 13S- 90 2,382,455 8/ 45 Turechek 166-204 XR 2,555,647 6/51 King 166--204 2,603,294 7/52 Barnes 166--204 2,726,722 12/55 Baker 166-204 2,743,789 5/56 Brown 166-204 XR 3,061,012 10/ 62 Moosman 166-204 XR CHARLES E. OCONNELL, Primary Examiner.

EDWARD V. BENHAM, Examiner.

Claims (1)

1. IN A PACKING STRUCTURE FOR FORMING A SEAL BETWEEN A ROD-LIKE ELEMENT AND A SURROUNDING WALL OF A WELL PIPE OR THE LIKE: A SUBSTANTIALLY CYLINDRICALLY-SHAPED RESILIENT PACKER MOUNTED ON THE ROD-LIKE ELEMENT; A PAIR OF ANNULAR RING ELEMENTS CARRIED ON SAID ROD-LIKE ELEMENT AND EACH HAVING A CONE SHAPED SURFACE ON ONE END THEREOF, ONE OF SAID RING ELEMENTS ABUTTING AN END OF SAID PACKER; AN EXPANSIBLE SEGMENTAL BACK-UP RING CARRIED ON THE ROD-LIKE ELEMENT AND HAVING INVERTED CONE SHAPED SURFACES ON EACH END THEREOF, SAID SEGMENTAL BACK-UP RING BEING INTERPOSED BETWEEN SAID PAIR OF ANNULAR RING ELEMENTS WITH THE CONE SURFACE OF EACH ANNULAR RING ELEMENT ABUTTING RESPECTIVELY THE INVERTED CONE SURFACES OF SAID SEGMENTAL BACK-UP RING, SAID SEGMENTAL BACK-UP RING INCLUDING A PLURALITY OF METALLIC SEGMENTS; RESILIENT MEANS CIRCUMSCRIBING SAID SEGMENTAL BACK-UP RING FOR MAINTAINING THE SEGMENTS IN A RETRACTED POSITION AS A UNIT; MEANS ABUTTING THE OTHER OF SAID RING ELEMENTS AND MAINTAINING THE SAME STATIONARY WITH RESPECT TO SAID ONE RING ELEMENT; MEANS ENGAGING SAID PACKER ON THE END OPPOSITE TO THE END ENGAGING SAID ONE RING ELEMENT FOR COMPRESSING SAID PACKER LONGITUDINALLY AND EXPANDING THE SAME TRANSVERSELY WHILE ALSO CAUSING SAID ANNULAR RING ELEMENTS TO MOVE TOWARD ONE ANOTHER TO RADIALLY EXPAND SAID SEGMENTAL BACK-UP RING; AND MEANS ON EACH OF SAID ANNULAR RING ELEMENTS AND ON EACH END OF SAID EXPANSIBLE SEGMENTAL BACK-UP RING FOR LIMITING RADIAL EXPANSION OF THE SAME TO A PREDETERMINED AMOUNT

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