US3029873A - Combination bridging plug and combustion chamber - Google Patents

Description

V. D. HANES A ril 17,1962

COMBINATION BRIDGING PLUG AND COMBUSTION CHAMBER 3 Sheets-Sheet 1 Filed July 22, 1957 INVENTOR. mus/141v DEA/V HANES 2 m 1 ATTORNEY April 17, 1952 v. D. HANES 3,029,873

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United rates Patent 3,02%,873 COMBHQATIQN ERHDGTNG PLUG AND UZBP/ihUSTEGN CHAMBER Vaughan Dean Hanes, West Covina, Calih, assignor to Aerojet-General Corporation, Azusa, Califi, a corporation of )hio Filed July 22, 1957, Ser. No. 673,344) 14 fl-aims. (Cl. 166-63) This invention relates to oil well tools. More particularly, the invention relates to oil well bridging plugs of the type which are run into a well on a wire line and then expanded and locked into position by means of high pressure gas generated by the burning of propellants in a closed chamber.

The invention described herein is a modification of the invention described and illustrated in my copending patent applications filed simultaneously herewith, Serial Nos. 673,339, 673,260 and 673,298.

Bridging plugs are employed in oil wells for the purpose of forming a barrier in the well bore. The barrier may be either permanent or temporary, and may be located either in the well casing or in the unc-ased portion of the well bore. The barrier, thus formed, serves to separate the well bore into upper and lower sections which are isolated from each other. A pressure differential may exist across the bridging plug and may vary from a few pounds per square inch to several thousand pounds per square inch.

The bridging plug of the present invention is intended for use primarily in those cases where the pressure ditferential is high across the bridging plug.

Heretofore, it has been the practice, when establishing a high pressure barrier in a well, to employ bridging plugs which are relatively large and which therefore contain large amounts of metal which must be drilled up when it is desired to remove them from the well. Such bridging plugs are relatively complicated and expensive to manufacture.

It is an object of the present invention to provide a high pressure bridging plug which is relatively small, simple in construction and cheap to make.

Another object is to provide a bridging plug and propellant combustion chamber combination adapted to be attached together to form a gas pressure setting bridging plug arrangement.

In recent years the method of setting bridging plugs Formerly, the plugs were run into the well on drill pipe or tubing, necessitating the use of a derrick and rotary drilling equipment at a cost sometimes of several thousand dollars, for the entire job. In recent years, the development of propellantactivated setting tools has made possible the running of the bridging plugs on a wire line instead of on pipe with a consequent large savings in expenses.

It is an object of the present invention to provide a bridging plug of the propellant-activated type, for wire line operation. Propellant-activated bridging plugs of the high pressure type, as heretofore constructed, required the use of separate, detachable setting tools containing the'propellant-activated mechanism which adds to the cost and expense of setting the plug.

It is an object of the present invention to provide a high pressure bridging plug of the wire line type which requires a separate combustion chamber but does not require a separate setting tool and thus reduces the cost of setting the plug.

Other objects and advantages will be apparent from the following description and drawings disclosing several embodiments of the invention.

FIGURES 1a and 1b show in longitudinal section one embodiment of the invention in the running in position.

The left hand end of FIGURE 1b showing a wire line running to the surface, and the left hand end of FIGURE 1a being a continuation of FIGURE 1b.

FIGURE 2 shows the parts of FIGURE 1a set in an oil well casing.

FTGURE 3 shows in longitudinal section a modified form of the invention in which the lower end of the bridging plug is equipped with only one set of slips.

FIGURE 4 shows the parts of FIGURE 3 set in an oil Well casing.

Referring to FIGURE 1, the numeral 1 indicates a well casing, Disposed within the well casing 1 and supported by awire line 2, is a bridging plug 3 and a combustion chamber 4, in the running-in position.

The bridging plug 3 comprises six major parts which are movable relative to each other. These parts are: a piston 5, acylinder 6, a floating sleeve 7, a floating body 8, upper and lower wedge slips 9, and a compressible packer sleeve 10. The piston 5 andcylinder 6 constitute a telescopic housing on the exterior of which the well wall engaging parts are mounted.

a The combustion chamber 4 comprises three major parts not movable in relation to each other. These parts areupper plug 11, lower plug 12, andcombustion cylinder 13.

The piston 5 is formed in two parts, the lower member being provided at its lower end with an enlargedhead 14 forming annular shoulder orabutment 14a, and arecess body 15 and an upwardly extending cylindrical shank 16 of reduced diameter, to which is connected as by the threads 17, an enlarged tubular upper piston member 18 a peripheral shoulder being thus formed between shank 16 and upper piston member 18.

Thecylinder 6 is slidably mounted on the shank 16 and piston member 18. To this end, thecylinder 6 is provided with a tubular lower portion 19 which slidably engages the outer surface of the piston member 18 and has an inwardly turnedflange 20 at its lower end slidably engaging the exterior surface of the tubular shank 16.

A suitable sealing means, such as the 0 rings 21, are mounted in theflange 20 in sealing relation with the exterior surface of the shank 16. The upper portion of thecylinder 6 is enlarged as indicated at 2-2 to provide a downwardly facing annular shoulder orabutment 23 against which the upper wedge slips 9 are supported in their retracted position, as shown in FIGURE 1. The interior'of thecylinder 6, above theflange 20, which slidably engages the exterior surface of the piston 5, forms a pressure orexpansion chamber 24 below the lower end of the upper member 18 of the piston. Sealing means, such as the O ring 25', is positioned in the exterior surface 'of the piston member 18 in sealing engagement between the walls of the cylinder 4 and the piston member 18.

The floating sleeve 7 is tubular in form with its interior surface, as indicated at 26, in slidable engagement with the exterior surface of the enlargedhead 14 and its interior surface, as indicated at 27, in slidable engagement with the exterior surface of the tubular portion 19 of thecylinder 6. The lower outer portion of the floating sleeve 7 is tapered downwardly and inwardly to form a frustoconical seat 28 for the lower wedge slips 9. The lower wedge slips are normally held in their retracted position, supported by theshoulder 14a, by any suitable means, such as shear pins 29 attached to the floating sleeve 7 as indicated in FIGURE 1.

The upper end of the floating sleeve 7 terminates in an upwardly facingannular shoulder seat 30 which serves as a seat for the lower end of the cylindrical, resilient packer sleeve 10.

The floating body 8 is tubular in form with its interior surface 31 in slidable engagement with the exterior surface of thecylinder 6. The upper outer portion of the floating body 8 is tapered upwardly and inwardly to form a frustoconical seat 32 for the upper wedge slips 9. The upper wedge slips are normally held in their retracted position, by any suitable means, such as the shear p1ns 33 attached to the floating body 8.

The lower end of the floating body 8 terminates in a downwardly facingannular shoulder seat 34 which serves as a seat for the upper end of the cylindrical, resilient packer sleeve 10.

In order to lock thecylinders 6 and piston in the set position, the outer surfaces of piston member 18 is provided with a series of vertically spaced, downwardly facing teeth 35. The teeth 35 are adapted to engage a series of vertically spaced, upwardly facingteeth 36 formed on the inner face of the wedge locks 37 mounted inrecess 38 formed in the upper end of thecylinder 6. The bearingwall 39 of therecess 38 is tapered downwardly and inwardly. A compression body of any suitable material, such as an 0ring 40, is mounted in therecess 38 between the upper surface of the wedge locks 37 and the lower surface of aretainer plate 41. Theretainer plate 41 is attached to thecylinder 6, by any suitable means, such as the screws 42.

The cylindrical resilient packer sleeve is mounted between theshoulder seats 30 and 34 and has its interior surface in slidable engagement with the exterior surface of thecylinder 6.

The piston member 18 is provided with theaxial hole 43 and at its upper end with the transverse holes 44 (FIG. 2).

The shank 16 is provided with the counterbores 45 and 46, thehole 47 and the transverse holes 48. A screen, such as theplate 49 with itsholes 50 may be placed between the lower surface 51 of the member 18 and theupper surface 52 of the shank 16.

Referring to FIGURE 1, the combustion chamber 4 is provided at its upper end with a reduced diameter to which is connected theunion nut 53 by the threads 54. The cylindricalupper plug 11 is provided with the upper shank 55, the lower shank 56, the flange 57 between the upper shank 55 and lower shank 56, and the axial hole 58 in which is mounted the insulated electrical connection device 59. The wireline cable head 60, of a suitable type, details not shown, is attached to the upper end of upper shank 55 by the threads 61. The lower shank 56 of theupper plug 11, is adapted to fit into the axial bore 62 provided in thecombustion cylinder 13. A suitable sealing means, such as the O ring 63, is mounted on the lower shank 56 in sealing engagement with the interior surface 64, formed by the bore 62, of thecombustion cylinder 13.

Theupper plug 11 is attached to thecombustion cylinder 13, by means of its flange 57,union nut 53 and the threads 54. Theupper plug 11 can be removed from the combustion chamber 4 by unscrewing the threads 54.

The electrical connection device 59, is mounted in the axial hole 58 of theupper plug 11, and consists of the tubular insulating material 65 mounted within the axial hole 58 and supported between the insulating-sealingwashers 66 and 67 and retained in place by means ofsupport washers 68 and 69, the electrical rod 70, the lower enlarged head 71 of the rod 70, and nut 72 on threads 73 at the upper end of rod 70. The electrical rod 70 passes through the axial hole in the tubular insulating material 65, the holes in the insulating-sealingwashers 66 and 67, and the holes in thesupport washers 68 and 69. The insulating-sealingwashers 66 and 67 are mounted in countersunk bores 74 and 75 provided in theupper plug 11. The electrical connecting device 59 seals the axial hole 58 by means of the tubular insulating material 65 and the insulating-sealingend washers 66 and 67 being compressed and expanded between thesupport washers 68 and 69 by means of the rod 70, the enlarged head 71, the nut 72 and the thread 73.

The insulatedelectric cable 76 is clamped against nut 72 on the rod 70 by means of the nut 77. The electric 4 cable may extend to the surface by any suitable means such as thewire line 2.

The combustion chamber 4 is provided at its lower end with the lower plug 12. The lower plug 12 has the upper shank 78 adapted to fit into the axial bore 62 and to seal said bore 62 by means of suitable sealing means, such as the 0 ring 79. The lower plug 12 also is provided with the downward extendingshank 80 having flange 81 located between theshank 78 and 80. The lower plug is attached to thecombustion cylinder 13 by means of the threads 82.

The upper surface of the shank 78 is provided with the counterbore 33 in which may be mounted a screen, as indicated by the body 84, having screen holes 85, The lower plug 12 is provided with anaxial passageway 86. The extendingshank 80 is adapted to fit into theaxial hole 43 of the piston member 18. Sealing means such as the 0ring 87 is mounted in the exterior surface of the extendingshank 89 in sealing engagement between the walls of the piston member 18 and theshank 80.

The combustion chamber 4 is slidably and shearable connected to the bridge plug 3 by means of the shear pins 38 and theshoulders 89 provided in theextension shank 86 of the combustion chamber 4.

A charge of gas generating propellant grain 90 is positioned in the axial bore 62 of thecombustion cylinder 13 between theupper plug 11 and thelower plug 13. An electric igniter of any suitable type such as thesquib 91, is positioned in the lower end of the propellant grain 90 and retained in place by the plug 92. The insulated lead 93 of thesquib 91, is connected to the enlarged head 71, of the rod 70, by any suitable means such as the wraps 94 around the head 71 and the ground lead 95 of thesquib 91 is grounded to the combustion chamber 4, by any suitable means, such as the screw 96 to complete the electric circuit. A resilient means, such as the spring 97 may be used to support the propellant grain 90 above the screen body 84.

The propellant grain 90 consists of a cylindricalgas producing propellant 98 in which is mounted thesquib 91. A quantity ofigniter material 99, such as a mixture of black powder and magnesium may be placed between thepropellant 98 and thesquib 91 to assist in ignition of the propellant grain 90. The propellant grain 90 is provided with the external covering 100 to prevent burning of the propellant on any other surface than its lower end to produce an end burning grain. The combined volume of the bore 62, the counterbore 83, thepassageway 86, thehole 43, the counterbore 46, thehole 47, the communicatingtransverse holes 48 and thepressure chamber 24 from a closed fiuid chamber within the intelrioro, of the combustion chamber 4 and the bridging P FIGURE 2 illustrates the bridging plug of FIGURE 1 in a set position in the wall casing 1. Upon application of electrical current, from any suitable source such as a wire line service unit, theelectric squib 91 is fired, igniting theigniter material 99 and initiating the burning of thepropellant 98.

The gas pressure generated by the burning of the propellant grain 90 within the combustion chamber 4 causes thecylinder 6 to move downwardly on the shank 16 of the piston 5, and in so doing shears the pins 33 and 29, releasing the upper and lower wedge slips 9. Continued downward movement of thecylinder 6 with respect to the piston 5 pushes the floating sleeve 7 and the floating body 8 downwardly. The compressible packer sleeve 10, being restrained between theshoulders 30 and 34 is compressed and expanded laterally until packer sleeve 10 is tightly engaged with theinner wall 101 of the casing 1 as indicated in FIGURE 2. At the same time, downward movement of thecylinder 6 in respect to the piston 5, forces the upper and lower wedge slips 9 into contact with theinner surface 101 of casing 1 due to movement on the frustoconical seats 28 and 32. Also, at the same time, downward movement of thecylinder 6 in respect to the piston causes theteeth 36 of the wedge lock 37 to engage the teeth 35 of the piston member 18 to lock thecylinder 6 against any subsequent upward movement, and thus maintaining the packer sleeve in sealing engagement with the well casing 1.

Continued build-up of pressure will cause the shear pins 88 to shear, thereby releasing the combustion chamber 4 from the bridging plug 3 and releasing the gas pressure from the bridging plug 3 and the combustion chamber 4.

The expanded packer sleeve 10 together with the expanded upper and lower slips 9 will enable the bridging plug 3 to withstand high difierential pressures in either direction.

The shearing of the pins 88 releases the combustion chamber 4 and thewire line 2 from the bridging plug. Thewire line 2 and combustion chamber 4 may be removed from the well.

. FIGURE 3 illustrates a variation of the bridging plug shown in FIGURES 1 and Z'Which has two sets of wedge slips 9, these being so positioned as to prevent movement in either direction in the well casing -1. Sometimes, a bridging plug is used to support pressure in the downward direction only. In this case it is customary to provide the bridging plug with only one set of wedge slips toprevent downward movement of the plug in the casing.

Referring to FIGURE 3, the numeral 120 indicates a single slip bridging plug, in the running-in position, disposed within the oil well casing 1 and supported on a wire line not shown. The bridgingplug 120 comprises five major parts which are movable in relation to each Other. These parts are: a piston 121, acylinder 122, a

,floatingbody 123, wedge slips 124, and acompressible packer sleeve 125.

The piston 121 is provided at its lower end withanenlarged head 126 forming an upwardly facingannular shoulder 127, a recessedbody 128 having an upwardly extending shank 129 of 'still further reduced diameter to which is connected, as by the threads 130, the piston member 121.

Thecylinder 122 is slidably mounted on the shank 129 and the piston member 121. To accomplish this, thecylinder 122 is provided with a tubular lower portion 132 which slidably engages the outer surface of the piston member 131 and has an inwardly turnedflange 133 at its lower end, slidably engaging the exterior surface of the shank 129. Suitable sealing means such as the 0 rings 134, are mounted in theflange 133 and the 0 rings 135 are mounted in the piston member 131 to form an expansion chamber 136. The upper end of thecylinder 122 is provided with theenlarged head 137 forming a downwardly facingshoulder seat 137a that serves as a seat for the upper end of theresilient packer sleeve 125.

The floatingbody 123 is tubular in form with itsinten'or surfaces 138 in slidable engagement with the exterior surface of thetubular body 128 and itsinterior surface 139 in slidable engagement with the exterior surface of thecylinder 122. The lower portion of the floatingbody 123 is tapered downwardly and inwardly to form a frustoconical seat 140 for the wedge slips 124. The wedge slips 124 are normally held in their retracted position, resting on theshoulder 127, by any suitable means, such as the shear pins 141, attached to the piston 121.

The upper end of the floatingbody 123 terminates in an upwardly facingannular shoulder 142 which serves as a seat for the lower end of theresilient packer sleeve 125. The locking arrangement is similar to that described for the bridging plug of FIGURE 1. Fluid passageways are also provided in the plug of FIGURE 3 similar to those of the plug of FIGURE 1.

Acombustion chamber device 143, similar to the combustion chamber 4 of FIGURE 1, is attached by shearable means not described to the bridgingplug 120 as indicated at the numeral 144.

FIGURE 4 illustrates the device of FIGURE 3 in set .position in the well casing 1. High pressure gas supplied by thecombustion chamber 143 into the expansion chamber 136 causes thecylinder 122 to move downwardly in relation to'the shank 129 and in so doing shears thepins 141, releasing the wedge slips 124. Continued downward movement compresses theresilient packer sleeve 125 between the shoulders 137a'and 142 and expands it into sealing engagement with the casing 1 and in sealing engagement with theexterior surface 145 of thecylinder 122. At the same time, continued gas pressure build-up in thecombustion chamber 143 and bridging plug sets the wedge slips 124 into the casing 1 and shears out the retaining means to release thecombustion chamber 143 from theplug 120. The locking means retainslthe bridging plug in the set condition.

When fluid pressure is applied to the casing -1 above the set bridging plug of FIGURE 4, the fluid is prevented from flowing downward in the casing 1 due to the sealing of the packer sleeve against the interior of the casing 1 and due to the holding action of the wedge slips 124 into the casing 1. I

Theexterior surface 145 of thecylinder 122 forms a piston rod type engagement with the interior surface of thepacker sleeve 125. Application of pressure to the upper side of thecasing sealing means of the bridging plug causes thepacker sleeve 125 to be compressed and 125. Therefore, the bridging plug is pressure responsive after being set and thereby automatically increases its sealing engagement with the casing,

I claim:

1. Well apparatus comprising: a piston, a cylinder slidably receiving said piston,'a plurality of wedge slips surrounding said piston and said cylinder, a first means for supporting one of said wedge slips attached to said cylinder, a second means for supporting one of said wedge slips attached to said piston and extending through said cylinder, a packer sleeve surrounding said cylinder and positioned between said wedge slips, a plurality of means for expanding said wedge slips surrounding said cylinder and positioned between said wedge slips and said packer sleeve, said piston having a passageway therethrough in communication with said cylinder, means for generating a fluid positioned remote to said piston and cylinder, and a means for providing a passageway for fluid attached to said fluid generating means and said piston and in communication with the piston passageway and said fluid generating means.

2. Well apparatus as defined in claim 1 and in addie tion: means for locking attached to said piston and said cylinder, said locking means used to prevent movement in a direction reversed to that desired.

3. Well apparatus as defined in claim 1 and in addition: a shearable pin interconnected to said passageway means and said piston.

4. Well apparatus as defined in claim 1 wherein said fluid generating means comprises: means for forming a combustion chamber, a solid propellant arranged in said chamber forming means, means for igniting said propellant arranged in said chamber forming means.

5. Well apparatus as defined in claim 1 and in addition: a means for attaching said passageway means to said piston and connected thereto.

6. Well apparatus comprising: a piston, a cylinder slidably receiving said piston, said cylinder having an inwardly extending flange contacting said piston, an enlarged head attached to said piston and extending exacaaeva ternally of said cylinder past said cylinder fiange, said cylinder having an outwardly extending enlarged portion thereon, wedge slips circumscribing said piston and said cylinder and abutting said enlarged head and cylinder enlarged portion, a packer sleeve circumscribing said cylinder and positioned between said wedge slips, means for expanding said wedge slips positoned between said wedge slips and said packer sleeve, said piston having a passageway therethrough in communication with said cylinder, means for generating fiuid positioned remote to said piston and said cylinder, and a means for providing a passageway for fluid attached to said fluid generating means and said piston and in communication between said fluid generating means and said piston passageway.

7. Well apparatus as defined inclaim 6 and in addition: means for locking attached to said piston to said cylinder, said locking means used to prevent movement and direction reversed to that desired.

8. Well apparatus as defined inclaim 6 wherein said fluid generating means comprises means for forming a combustion chamber, a solid propellant arranged in said chamber forming means, and means for igniting said propellant arranged in said chamber forming means.

9. Well apparatus as defined inclaim 6 and in addition: a shearable pin interconnected to said passageway means and said piston.

10. Well apparatus as defined in claim 9 in which the sliearable pin is constructed of a material that will shear at a pressure greater than that required to set the slips and sleeve packer.

11. Well apparatus comprising: a piston consisting of a tubular member, an enlarged head having a cylindrical shank attached to said piston tubular member, a cylinder slidably receiving said tubular member, said cylinder having a flange extending radially inwardly in contact with said cylindrical shank, said tubular member having a port thercthrough positioned adjacent the said cylindrical shank thereby having the interior of said piston tubular member in communication with said cylinder, said cylinder havingan enlarged portion extending radially outwardly, wedge slips circumscribing said cylinder and said cylindrical shank and abutting said cylinder enlarged portion and said enlarged head, an annulus shaped packer sleeve circumscribing said cylinder and positioned between said wedge slips, a means for expanding wedge slips positioned between said sleeve packer and said wedge slip, a means for generating fiuid remotely positioned in relation to said tubular member and cylinder and a means for providing a passageway attached to said fluid generating means and said tubular member and in communication with said fluid generating means and said tubular member port.

12. Well apparatus as defined inclaim 11 and in addition means for locking attached to said tubular member and said cylinder to prevent movement in a direction reverse to that desired.

13. Well apparatus as defined inclaim 11 wherein said fluid generating means comprises means for forming a combustion chamber, a solid propellant arranged in said chamber forming means, and a means for igniting said propellant arranged in saidchamber forming means 14. Well apparatus as defined inclaim 11 and in addition a shearable pin interconnected between said passage way means and said tubular member constructed of a material which will shear at a pressure greater than that required to set the wedge slips and the sleeve packer.

References Cited in the file of this patent UNITED STATES PATENTS 2,262,117 Roe Nov. 11, 1941 2,266,382 Quintrell et al Dec. 16, 1941 2,308,004 Hart Jan. 12, 1943 2,618,343 Conrad Nov. 18, 1952 2,640,547 Baker et al. June 2, 1953 2,675,877 Baker Apr. 20, 1954 2,807,325 Webb Sept. 24, 1957

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