US3062295A

US3062295A - Bridging plug

Info

Publication number: US3062295A
Application number: US807620A
Authority: US
Inventors: Hanes Vaughan Dean
Original assignee: Aerojet General Corp
Current assignee: Aerojet Rocketdyne Inc
Priority date: 1959-04-20
Filing date: 1959-04-20
Publication date: 1962-11-06
Anticipated expiration: 1979-11-06

Description

Nov. 6, 1962 v. D. HANES 3,062,295

BRIDGING PLUG Filed April 20, 1959 9 30% INVENTOR. I VAUGHAN DEAN HANES 7' IE.-7 IE-5 55. 5 M Q? ATTORNEY States This invention relates to well tools and particularly to oil well packers, bridging plugs, and similar devices of the kind in which a tubular resilient sleeve mounted on the tool is compressed axially and consequently expanded radially into sealing engagement with a well casing. Well tools of the kind referred also are usually provided with slips having serrated surfaces which are engaged with the inner surface of the well casing and serve to prevent upward or downward movement of the packer due to a pressure diiferential which may act on it. The slips may be arranged above the sleeve, below the sleeve, or both above and below the sleeve.

In many previously known well tools, the packer sleeve is initially engaged at each end on an annular shoulder or shoe on the tool which must be of smaller diameter than the well casing, thus leaving unsupported the annular portion of the rubber sleeve which extends when com pressed outwardly of the shoulder or shoe.

It is characteristic of slip type packers and similar tools that when the slips are in the expanded position they are of necessity spaced apart circumferentially. Therefore, the slips themselves cannot afford a continuous support for the ends of the packer sleeve.

It is therefore an object of the present invention to provide a novel expansible shoe construction in tools of the kind referred to for either or both ends of the resilient sleeve which will aiford a continuous support to the end of the sleeve engaged by the shoe.

With the above and other objects in view as will appear from the following specification and accompanying illustrative drawings, the invention comprises an oil well tool, having a resilient packing sleeve supported between shoes by which axial compression may be imposed on said sleeve to radially expand it. The tool is also provided with slip means. At least one of the shoes is provided with an auxiliary shoe arranged to expand radially when actuated. Separate elements are arranged effective to both expand said auxiliary shoe and the slip means, the auxiliary shoe and a ring of slips being efiective to fill the gaps between said separate shoe elements to provide a continuous supporting surface to the end of the packer engaged by said auxiliary shoe.

In the drawings:

FIG. 1 is a view partly in central vertical section showing a packer constructed according to the invention in set position in an oil well easing;

FIG. 2 is a vertical half section of the packer, the parts being shown retracted in the lowering position of the packer;

FIG. 3 is a fragmentary sectional view of a rupturable ring providing expandable shoes interfitting with a rupturable ring of slip elements in the lowering position of the packer;

FIG. 4 is a view similar to that of FIG. 3 but showing the parts when in set position;

FIG. 5 is a fragmentary view of a developed length of the rupturable shoe ring;

FIG. 6 is a top plan view of the part shown in FIG. 5;

FIG. 7 is a fragmentary end view of the rupturable ring of FIG. 5 taken on the line 7-7 of FIG. 5; and

FIG. 8 is a section of the rupturable ring of FIG. 5 taken on the line 8-8 of FIG. 5 through the projected portions of the ring.

Referring now to FIG. 1, the numeral 1 indicates an oil well casing with the packer generally indicated at 2, in set position therein.

The packer is provided with an upper shoe 3 mounted on an inner mandrel 6 which is mounted in a slidable axial bore in an outer mandrel 4 which is provided with an enlarged head 5 providing an abutment by which pressure may be applied to a lower shoe 7.

The lower shoe 7, formed as a frusto-conical member slidably mounted on the outer mandrel 4, engages in the conical bore of an auxiliary shoe member 9 formed as a ring arranged so as to be ruptured at intervals around its periphery when axial force is applied to the frustoconical shoe to provide a plurality of separate auxiliary shoe elements.

The frusto-conical shoe 7 is also forced into the conical bore of a member generally indicated at 10 which is formed as a rupturable ring which breaks into a plurality of slips 14 when head 5 forces the ring 10 over the frustoconical shoe 7.

The auxiliary shoe member 9 is interposed between the slip ring member 10 and the packer sleeve 8 and rests upon said slip ring member.

The packer sleeve 8 of resilient material is mounted between the upper shoe 3 and the thick upper end of the =frusto-conical lower shoe 7 in the running-in position shown in FIG. 2. In this position it will be noted that the unbroken ring 10 of slips holds the narrow end of shoe 7 spaced well above the surface of head 5. In the set position shown in FIG. 1 the upper shoe 3 mounted on the sliding mandrel 4 and the head 5 have been forced toward one another, as will belater explained, with the result that the resilient sleeve 8 has been longitudinally compressed and consequently radially expanded into engagement with the casing as indicated at 11.

The movement of the shoe 3 and head 5 toward one another results in the thinner end of the frusto-conical lower shoe 7 being driven into the conical bores :of auxiliary shoe member 9 and slip member 10 which are formed so that the resulting ring stress breaks both rings 9 and 10 into a plurality of segments which are moved radially outward against the casing as indicated at

points

12 and 13 in FIG. 1. In this position it will be noted that the narrow end of shoe 7 is much more closely adjacent the surface of head 5.

Referring now to FIGS. 5 through 8 showing the arrangement of ring member 9, which forms an auxiliary shoe, the upper thickened rim 15 may be provided with a smooth peripheral rim or as shown with a sharp edge 30.

The ring 9 is formed with a plurality of downwardly extending portions 21 having edges 21a oppositely inclined. outwardly from the upper edge of the ring and leaving notches or spaces 18 between the portions 21. The inclined surface of contact between the auxiliary shoe elements 21 enables the slip elements 14 to support the shoe elements although the slip elements 14 move both upward and outward while the auxiliary shoe elements move only radially outward. Outward movement of the auxiliary shoe elements 21 progressively separates them but the upward movement of the slip elements 14 maintains the contact of the upper ends of slips 14 with the auxiliary shoe elements. The metal of the ring 9 between the spaces 18 and the upper edge of the ring is narrow and is reduced in thickness from front to back as indicated at 19 so that hoop stress set up in the ring can readily break it into a plurality of separate segments which are moved radially outward and the upper edges of which act as auxiliary shoes to support the lower edge of the resilient sleeve 8 which has also been radially expanded. The lower edge 8a of the sleeve 8 between the segments of the ring 9 is also supported as will appear later.

The ring 10 of slips is formed in a manner complementary to that of ring 9 as shown in FIG. 3. A plurality of slip segments 14 are connected together to form a ring by portions 17 of reduced thickness and height. The upper ends of the slip elements 14 are tapered at the same angle as the tapered depending portions 21 of the ring 9 and extend into the notches or spaces 18 between the projections 21.

The described construction of the ring leaves notches or spaces 16 between the lower edges of the projections 21 and the upper edges of the reduced thickness portions 17 of the ring 10. The edges of peripheral teeth on the slips is indicated at 20.

When the frusto-conical shoe 7 is forced into the conical bore of the slip ring 10 the reduced thickness portions 17 of the ring are ruptured similarly to the reduced thickness portions of ring 9, fractures of ring 10 being indicated at 22 in FIG. 4.

While any suitable means may be provided for effecting relative movement between the mandrel 6 and the slidable outer mandrel 4, the means shown, by way of example, in FIGS. 1 and 2 comprise a chamber 26 provided by a reduced diameter portion 31 of the mandrel 6 and an inturned flange 32 at the upper end of the outer mandrel 4. The chamber 26 may be fluid sealed as by the 0

rings

33 and 34.

The mandrel 6 is also provided with an axial chamber 35 closed at its lower end as indicated at 36 and at its upper end by the cable head 37 (FIG. 2). The cable head 37 can be attached to the mandrel 6 as by the shear pins 38 passing through holes 39 through the upper end of the sliding mandrel and through the head 37. The axial chamber 35 may be sealed at its upper end as by the O-ring 40 mounted in a peripheral groove in the cable head 37.

The axial chamber 35 communicates with the chamber 26 by means of the transverse ports 41 provided in the reduced portion 31 of the mandrel 6.

A propellant charge 29 (FIG. 2) is positioned in the axial chamber 35. The charge 29 is provided with a squib igniter 27 connected into an electric circuit provided by the leads 42 running through cable 45, ground lead 43 and ground 44. The cable 45 extends to the surface and supports the packer 2 in the casing 1. The propellant charge 29 is adapted to be ignited by firing the squib igniter 27 by completing an electrical circuit through the squib 27 by suitable equipment (not shown) at the surface.

The mandrel 6 is provided near its lower end with the upwardly facing teeth 46 adapted to mate with the downwardly facing teeth 47 of the lock part 48. The slidable outer mandrel 4 is provided at its lower end with the counterbore 49 adapted to receive the lock part 48. A plate 50, attached as by the screws 28, retains resilient ring 25 urging the lock part 48 inwardly to operative position in the counterbore 49.

Upon igniting the propellant charge 29 by the igniter squib 27, the evolution of gas of the burning propellant develops pressure in chamber 35 which is communicated through ports 41 to chamber 26 and forces the mandrel 6 downwardly and the slidable outer mandrel 4 with head 5 upwardly. As the frusto-conical shoe 7 is driven by the downward pressure acting on sleeve 8 into the conical bores of the ring members 9 and 10, they are broken into segments by the fracturing of the weakened portions 17 of ring 10 and portions 19 of ring 9 until the resilient sleeve 8 has reached a condition of maximum compression against the casing 1. Until rupture of the ring of slip 10 occurs the force exerted by head 5 is transmitted directly through shoe member 7 to the lower face of sleeve 8. By incorporation of proper design parameters the apparatus can be designed to insure that the force required to rupture is reached before the resilient sleeve 8 is fully compressed. After rupture of ring 10 the lower shoe 7 acts as a stationary wedge over which the separate slip members 14 are forced upwardly and radially outwardly into setting engagement with the well casing. The segments of the auxiliary shoe 9 taking part in the setting operation of slips 14 by engagement of the upper ends of the slips 14 with the depending portions 21 of auxiliary shoe ring 9, also forces ring 9 upwardly on shoe 7 causing rupture of the ring and outward movement of the parts of the auxiliary shoe.

In the set condition, as indicated in HG. 4, the greater portion of the area of the lower end face of the resilient sleeve 8 is engaged against the wide upper surface of the frusto-conical lower shoe 7 but the annulus 8a of the lower end face of sleeve 8, which has been radially expanded out of contact with shoe 7, is supported by a continuous surface partly provided by the upper edge of the elements of auxiliary shoe ring 9 and partly by the upper edge of the separated slip elements 14 of the ring 19. FIG. 4 shows in exaggerated form the protrusion of portions 23 of the lower edge of the sleeve 8 into the spaces left between the separated portions of ring 9, and engaged with the tops 24 of slips 14 which act as auxiliary lower shoes. A continuous shoe surface for the lower edge 8a of the sleeve 8 is provided by the described construction. It will be obvious that the auxiliary shoe 9 and slip structure 10 could be duplicated at the upper end of the resilient sleeve 8. Various other changes could be readily made such as forming the slip members 14 or segments of the ring 9 or both as separate members retained on the tool by a binding of metal wire or strap which would securely retain the parts in position on the tool until the wire or strap was ruptured by the ring stress developed in the setting operation as described, or the slip members and/ or auxiliary shoe members might be held in initial position by shear screws as is well known in the art. Also various other manners of causing relative motion of the mandrel 6 and slidable outer mandrel 4 to set the packer, may be provided, so that the invention is in no way limited by the embodiment specifically described and shown but only as defined by the scope of the appended claims.

I claim:

1. An oil well packer comprising a resilient packer sleeve adapted, when axially compressed, to engage the wall of an oil well casing, first and second shoes on opposite sides of said packer sleeve and coaxial therewith, a slip ring surrounding said second shoe, ring means surrounding said second shoe and positioned between said slip ring and said packer sleeve, said slip ring and said ring means each having circumferentially spaced reduced thickness portions, means operatively associated with said first shoe and said slip ring for forcing said slip ring, said ring means and said second shoe toward said first shoe to compress said packer sleeve, and means for rupturing said slip ring and said ring means at said reduced thickness portions during movement thereof toward said first shoe.

2. An oil well packer as set forth in claim 1 and, in addition, said reduced thickness portions of said slip ring being alternately positioned relative to said reduced thickness portions of said ring means whereby said ring means, when ruptured, provides a constant support for portions of said packer sleeve and said slip ring, when ruptured, supports the remaining portions of said packer sleeve, thereby providing a continuous support for said packer sleeve.

3. An oil well packer comprising a resilient packer sleeve adapted, when axially compressed, to engage the Wall of an oil well casing, first and second frusto-conical shoes on opposite sides of said packer sleeve with the larger conical portions of said shoes being adjacent said packer sleeve and coaxial therewith, a slip ring engaging said frusto-conical shaped second shoe, ring means engaging said frusto-conical shaped second shoe and p0- sitioned between said slip ring and said packer sleeve, said slip ring and said ring means each having circumferentially spaced reduced thickness portions whereby said slip ring and said ring means may be ruptured at said reduced thickness portions upon movement thereof toward said first shoe, and means operatively associated with said first shoe and said slip ring for forcing said slip ring, said ring means and said second shoe toward said first shoe, thereby rupturing said slip ring and said ring means and compressing said packer sleeve.

4. An oil well packer comprising a resilient packer sleeve adapted, when axially compressed, to engage the Wall of an oil Well casing, first and second frusto-conical shoes on opposite sides of said packer sleeve with the larger conical portions of said shoes being adjacent said packer sleeve and coaxial therewith, a slip ring surrounding said frust-o-conical shaped second shoe, said slip ring having notches opening toward said packer sleeve and circumferentially spaced reduced thickness portions whereby said slip ring may be ruptured at said reduced thickness portions upon movement thereof toward said first shoe, auxiliary shoe means surrounding said second shoe member and positioned between said packer sleeve and said slip ring, said auxiliary shoe means having depending Wedge-shaped portions that engage said slip ring notches, means operatlvely associated with said first shoe and said slip ring for forcing said slip ring, said auxiliary shoe means and said second shoe toward said first shoe, thereby rupturing said slip ring and compressing said packer sleeve, said slip ring and said auxiliary shoe means thereby contacting said packer sleeve to act as a support therefor.

5. An oil well packer as set forth in claim 4 in which said slip ring has teeth positioned on its periphery for contacting the Wall of the oil Well casing.

References (Iited in the file of this patent UNITED STATES PATENTS 2,121,002 Baker June 21, 1938 2,467,801 Baker Apr. 19, 1949 2,546,377 Turechek Mar. 27, 1951 2,726,722 Baker Dec. 13, 1955 2,791,278 Clark May 7, 1957 2,897,325 WVebb Sept. 24-, 1957 2,896,724 Baker July 28, 1959