Apparatus for sealing a well casing

Abstract

A method and apparatus for sealing a well casing, when a length of production tubing is disposed within the well casing, utilizes a sealing means having a first diameter less than the diameter of the production tubing, and the sealing means is compressible to a second diameter which sealingly conforms to the diameter of the well casing, to prevent fluids disposed in the well casing below the sealing means from flowing through the well casing to above the sealing means. .Iadd. To support the sealing means when it has been sealingly conformed to the diameter of the well casing, the well bore apparatus of the invention further includes upper and lower sets of opposed reinforcing members which are mounted on the body of the well bore apparatus above and below the sealing means and operatively arranged to be respectively swung outwardly from the body to an extended position for supporting the upper and lower end portions of the sealing means against longitudinal movement in the well casing. .Iaddend.

We claim: 
     
       1. An elastomeric sealing element for a bridge plug for use within a well casing and production tubing, the diameter of the production tubing being smaller than the diameter of the well casing, comprising: a generally tubular-shaped elastomeric member having first and second ends and a unitary wall portion therebetween;   the elastomeric member having a normal, unstressed configuration, wherein the diameter thereof varies along the longitudinal axis of the elastomeric member, with the diameter intermediate the ends of the elastomeric member being larger than the diameter at the ends of the elastomeric member;   the elastomeric member being elongatable along its longitudinal axis whereby the diameter intermediate the ends of the elastomeric member is substantially the same as the diameter of its ends so that the elastomeric member may pass through the production tubing; and   the elastomeric member being compressible along its longitudinal axis to a configuration where said ends of said elastomeric member are in contact with each other whereby said unitary wall portion sealingly conforms to the well casing.   
     
     
       2. The sealing element of claim 1, including a means for restraining the elastomeric member in its elongated configuration, whereby the diameter intermediate the ends of the elastomeric member is substantially the same as the diameter of its ends. 
     
     
       3. The sealing element of claim 1, wherein the wall portion intermediate the ends of the elastomeric member has a reduced wall thickness intermediate the ends of the wall portion. 
     
     
       4. The sealing element of claim 1, wherein the elastomeric member has disposed in each of its ends an insert member having an axial passageway therethrough coextensive with the longitudinal axis of the elastomeric member and adapted to receive an elongate mandrel therethrough. 
     
     
       5. An elastomeric sealing element for a bridge plug for use within a well caing and production tubing, the diameter of the production tubing being smaller than the diameter of the well casing, comprising: A. a generally tubular-shaped elastomeric member having first and second ends and a wall portion therebetween, the elastomeric member having a normal, unstressed configuration, wherein the diameter thereof varies along the longitudinal axis of the elastomeric member, with the diameter intermediate the ends of the elastomeric member being larger than the diameter at the ends of the elastomeric member,   the elastomeric member being elongatable along its longitudinal axis whereby the diameter intermediate the ends of the elastomeric member is substantially the same as the diameter of its ends so that the elastomeric member may pass through the production tubing, and   the elastomeric member being compressible along its longitudinal axis whereby the ends of the elastomeric member can be forced toward and into close proximity with one another while a portion of the wall portion sealingly conforms to the well casing; and     B. means for restraining the elastomeric member in its elongated configuration, whereby the diameter intermediate the ends of the elastomeric member is substantially the same as the diameter of its ends, the restraining means being a frangible, thin-walled tubular member, whereby upon compressive force being exerted upon the elastomeric member, the tubular member breaks and allows the elastomeric member to assume its normal unstressed configuration.     
     
     
       6. The sealing element of claim 5, wherein the tubular member is formed of a cloth material. 
     
     
       7. The sealing element of claim 5, wherein the tubular member is formed of a metallic material. 
     
     
       8. An elastomeric sealing element for a bridge plug for use within a well casing and production tubing, the diameter of the production tubing being smaller than the diameter of the well casing, comprising: A. a generally tubular-shaped elastomeric member having first and second ends and a wall portion therebewteen, the elastomeric member having a normal, unstressed configuration, wherein the diameter thereof varies along the longitudinal axis of the elastomeric member, with the diameter intermediate the ends of the elastomeric member being larger than the diameter at the ends of the elastomeric member,   the elastomeric member being elongatable along its longitudinal axis whereby the diameter intermediate the ends of the elastomeric member is substantially the same as the diameter of its ends so that the elastomeric member may pass through the production tubing, and   the elastomeric member being compressible along its longitudinal axis whereby the ends of the elastomeric member can be forced toward and into close proximity with one another while a portion of the wall portion sealingly conforms to the well casing, and     B. An insert member disposed in each end of the elastomeric member,   each insert member having an axial passageway therethrough coextensive with the longitudinal axis of the elastomeric member and adapted to receive an elongate mandrel therethrough, and each insert member including a plurality of radially spaced anchor wires extending into the wall portion of the elastomeric member.     
     
     
       9. The sealing element of claim 8, wherein at least some of the anchor wires have an eyelet disposed at their ends disposed in the elastomeric member, each eyelet lying in a plane which is substantially parallel with the longitudinal axis of the elastomeric member. .Iadd. 
     
     
       10.  A through-tubing bridge plug adapted to be lowered through a tubing string in a cased well bore and set in an interval thereof below the lower end of the tubing string comprising: an elongated body;   packer means including a plurality of tubular elastomeric sealing members mounted around said body and cooperatively arranged with their intermediate portions respectively having an external diameter larger than the diameter of their upper and lower end portions when said sealing members are in a normal, unstressed configuration so that their intermediate portions will be doubled over and flattened together in response to oppositely-directed forces compressing their upper and lower end portions together for expanding said intermediate portions of said sealing members outwardly into sealing engagement with a well bore casing;   means releasably retaining each of said sealing members on said body in an initial longitudinally-elongated configuration to temporarily reduce the diameter of said intermediate portions of said sealing members to facilitate the passage of said bridge plug through a tubing string, said retaining means being operatively arranged to release said sealing members for outward expansion of their intermediate portions into sealing engagement with a well bore casing as their upper and lower end portions are compressed together by said oppositely-directed forces;   reinforcing means including upper and lower sets of opposed reinforcing members on said body above and below said packer means and respectively having petal-like projections disposed around said body and normally inclined outwardly therefrom, each set of said opposed reinforcing members having their respective projections angularly aligned with one another so that as said oppositely-directed forces move said reinforcing members toward said packer means, said projections will be swung away from said body through an arc of less than 90-degrees to laterally-extended positions where their opposed faces will be coengaged against one another for supporting said end portions of said sealing members against further longitudinal movement; and   upper and lower anchoring means cooperatively arranged on said body above and below said reinforcing means for movement into anchoring engagement with a well bore casing after said intermediate portions of said sealing members are expanded outwardly into sealing engagement therewith..Iaddend. .Iadd.11. The through-tubing bridge plug of claim 10 further including means cooperatively arranged on each of said petal-like projections for strengthening them against deflection once said projections have been swung to their said laterally-extended positions and their said opposed faces are coengaged with one another..Iaddend. .Iadd.12. The through-tubing bridge plug of claim 10 wherein at least a major portion of the longitudinal edges of said petal-like projections are respectively bent over for reinforcing the intermediate portions of said projections after their opposed faces have been coengaged with one another..Iaddend.   
     
     
        .Iadd.13.  A through-tubing bridge plug adapted to be lowered through a tubing string in a cased well bore and set in a selected interval thereof below the lower end of the tubing string comprising: elongated body means;   sealing means including a plurality of tubular elastomeric packer members movably disposed on said body means with their end portions capable of abutting one another, each of said packer members being cooperatively arranged with its intermediate portion having an external diameter larger than the diameter of its end portions when said packer member is in a normal, unstressed configuration so that said intermediate portions of said packer members will be doubled over and flattened together in response to oppositely-directed longitudinal forces imposed on their end portions for extending said intermediate portions of said packer members outwardly into sealing engagement with a well bore casing;   means releasably retaining each of said packer members on said body in an initial longitudinally-elongated configuration to temporarily reduce the diameter of said intermediate portions of said packer members to facilitate the passage of said bridge plug through a tubing string, said retaining means being operatively arranged to release said packer members for extension of their intermediate portions into sealing engagement with a well bore casing as their end portions are compressed together by said oppositely-directed longitudinal forces;   means releasably retaining each of said packer members on said body in an initial longitudinally-elongated configuration and reducing the diameter of said intermediate portions of said packer members to allow said bridge plug to be lowered through a tubing string, said retaining means being releasable in response to said oppositely-directed longitudinal forces to free said packer members to enable their intermediate portions to be extended outwardly into sealing engagement with a wall bore casing as their end portions are being compressed together;   reinforcing means including upper and lower opposed support members movably disposed on said body means above and below said sealing means and cooperatively arranged for supporting said end portions of said outwardly-extended packer member, each of said support members including multiple flat, petal-like projections uniformly spaced around said body means and initially inclined slightly outwardly therefrom, each of said opposed support members having the outer ends of their respective projections in angular alignment with one another so that in response to said oppositely-directed longitudinal forces acting on said opposed support members, said projections will be swung outwardly away from said body means through an arc of less than 90-degrees to coengage the opposed faces of the aligned projections with one another and dispose said projections against said end portions of said outwardly-extended packer members; and   upper and lower anchoring means cooperatively arranged on said body means above and below said reinforcing means for movement into anchoring engagement with a well bore casing after said packer members have been   
     
     
        extended into sealing engagement therewith..Iaddend. .Iadd.14.  The through-tubing bridge plug of claim 13 further including means cooperatively arranged on each of said petal-like projections for strengthening them against deflection once said projections have been swung to their outward positions and their said opposed faces are coengaged with one another..Iaddend. .Iadd.15. The through-tubing bridge plug of claim 13 wherein at least a major portion of the longitudinal edges of said petal-like projections are respectively bent over for reinforcing the intermediate portions of said projections after their opposed faces have been coengaged with one another..Iaddend. .Iadd.16. A through-tubing bridge plug adapted to be lowered through a tubing string in a cased well bore and set in an interval thereof below the lower end of the tubing string comprising: an elongated body;   a stack of tubular elastomeric sealing members mounted on said body with their respective end portions capable of being abutted with one another and respectively having intermediate portions with their external diameters being larger than the diameter of their end portions when said sealing members are in a normal, unstressed configuration and cooperatively arranged to be respectively doubled over and then flattened together in response to oppositely-directed forces moving said end portions together and expanding said intermediate portions of said sealing members outwardly into sealing engagement with a well bore casing;   retaining means releasably securing said sealing members in an elongated configuration along said body to temporarily reduce the external diameters of said intermediate portions of said sealing members to about the external diameter of their end portions so that said bridge plug may be lowered through a tubing string into a cased well bore interval, said retaining means being responsive to said oppositely-directed forces to free said said sealing members for movement of their end portions together and expansion of their intermediate portions outwardly into sealing engagement with a well bore casing as said end portions of said sealing members are flattened together;   upper and lower sets of opposed reinforcing members on said body above and below said sealing members and cooperatively arranged for respectively supporting the uppermost and lowermost ones of said sealing members, each of said reinforcing members including a base movably mounted on said body and a plurality of petal-like projections uniformly spaced around said base and initially inclined outwardly from said body, each set of said reinforcing members comprising two of said reinforcing members mounted so as to oppose one another with the outer ends of their projections respectively aligned with one another so that in response to said oppositely-directed longitudinal forces moving said upper and lower sets of reinforcing members against said stacked sealing members, said upper and lower reinforcing members will be respectively flattened against the end portions of said uppermost and lowermost sealing members as said projections are swung further outwardly from said body to laterally-extended positions for coengaging the opposed faces of each of said aligned projections with one another to support said expanded sealing members in sealing engagement with a well bore casing; and   upper and lower anchoring means mounted on said body above and below said upper and lower sets of reinforcing members and cooperatively arranged for anchoringly engaging a well bore casing upon expansion of said sealing members into sealing sealing engagement therewith..Iaddend. .Iadd.17. The through-tubing bridge plug of claim 16 further including means cooperatively arranged on each of said petal-like projections for strengthening them against deflection once said projections have been swung to their laterally-extended positions and their said opposed faces   
     
     
        are coengaged with one another..Iaddend. .Iadd.18.  The through-tubing bridge plug of claim 16 wherein at least a major portion of the longitudinal edges of said petal-like projections are respectively bent over for reinforcing the intermediate portions of said projections after their opposed faces have been coengaged with one another..Iaddend.