Millable bridge plug system

Abstract

A millable bridge plug system includes a mandrel, a sealing member, ring members, cone assemblies, and slip devices. The sealing member, ring members, cone assemblies and slip devices are positioned on and around the mandrel. Ring members push against an upper end and lower end of the sealing member. The sealing member has a surface interface contacting each of the ring members so that pressure from the ring members is exerted according to contact along the surface interface. The surface interface can have a curvature or be a double radiused surface. The ring members are pushed against the cone assemblies, and the ring members have ring surface interfaces contacting the cone assemblies. The pressure from the cone assemblies is exerted according to contact along the ring surface interface of the ring members. Coordination of the surface interfaces and ring surface interfaces control pressure to insure improved sealing against the wellbore.

I claim: 
     
         1 . A millable bridge plug system, comprising:
 a mandrel;   a sealing means positioned around the mandrel;   a plurality of ring members, a first ring member adjacent an upper end of said sealing means and a second ring member adjacent a lower end of said sealing means, wherein said upper end of said sealing means has a first means for resisting pressure by said first ring member when in contact with said first ring member, and wherein said lower end of said sealing means has a second means for resisting pressure by said second ring member when in contact with said second ring member;   a plurality of cone assemblies, a first cone assembly proximate to said first ring member and a second cone assembly proximate to said second ring member, said first ring member being between said first cone assembly and said sealing means, said second ring member being between said second cone assembly and said sealing means; and   a plurality of slip means for extending radially outward and engaging an inner surface of a surrounding borehole, a first slip means mounted around said mandrel and engaging said first cone assembly and a second slip means mounted around said mandrel and engaging said second cone assembly.   
     
     
         2 . The bridge plug system according to  claim 1 , wherein said first means for resisting pressure is comprised of a surface interface with a curvature, and
 wherein said second means for resisting pressure is comprised of a surface interface with a curvature.   
     
     
         3 . The bridge plug system according to  claim 2 , wherein pressures are exerted by said ring members on said upper end and said lower end of said sealing means. 
     
     
         4 . The bridge plug system according to  claim 3 , wherein deformation of said sealing means is dependent upon location of said pressures on curvatures of the surface interfaces of said upper end and said lower end of said sealing means. 
     
     
         5 . The bridge plug system according to  claim 1 , wherein said first means for resisting pressure is comprised of a double radiused surface, and
 wherein said second means for resisting pressure is comprised of a double radiused surface.   
     
     
         6 . The bridge plug system according to  claim 5 , wherein pressures are exerted by said ring members on said upper end and said lower end of said sealing means, and
 wherein deformation of said sealing means is dependent upon location of said pressures on the double radiused surfaces of said upper end and said lower end of said sealing means   
     
     
         7 . The bridge plug system according to  claim 1 , wherein said first ring member has a first ring means to resist pressure when in contact with said first cone assembly, and
 wherein said second ring member has a second ring means to resist pressure when in contact with said second cone assembly.   
     
     
         8 . The bridge plug system according to  claim 7 , wherein said first ring means for resisting pressure is comprised of a ring surface interface with a ring curvature, and
 wherein said second ring means for resisting pressure is comprised of a ring surface interface with a ring curvature.   
     
     
         9 . The bridge plug system according to  claim 8 , wherein pressures are exerted by said cone assemblies on said ring members,
 wherein deformation of said ring members is dependent upon location of pressures on the ring surface interfaces by said cone assemblies, and   wherein pressure exerted by said ring members on said upper end and said lower end of said sealing means is dependent upon location of said pressures on first and second means for resisting pressure of said sealing means and location of pressures on the ring surface interfaces by said cone assemblies.   
     
     
         10 . The bridge plug system according to  claim 7 , wherein said first ring means for resisting pressure is comprised of a single radiused surface, and
 wherein said second ring means for resisting pressure is comprised of a single radiused surface.   
     
     
         11 . The bridge plug system according to  claim 10 , wherein pressures are exerted by said cone assemblies on said ring members,
 wherein deformation of said ring members is dependent upon location of pressures on single radiused surfaces of said ring members, and   wherein pressure exerted by said ring members on said upper end and said lower end of said sealing means is dependent upon location of said pressures on the first and second means for resisting pressure of said sealing means and location of pressures on the single radiused surfaces by said cone assemblies.   
     
     
         12 . A millable bridge plug system, comprising:
 a mandrel;   a sealing means positioned around the mandrel;   a plurality of ring members, a first ring member adjacent an upper end of said sealing means and a second ring member adjacent a lower end of said sealing means, wherein said upper end of said sealing means has a double radiused surface in contact with said first ring member, and wherein said lower end of said sealing means has a double radiused surface in contact with said second ring member;   a plurality of cone assemblies, a first cone assembly proximate to said first ring member and a second cone assembly proximate to said second ring member, said first ring member being between said first cone assembly and said sealing means, said second ring member being between said second cone assembly and said sealing means; and   a plurality of slip means for extending radially outward and engaging an inner surface of a surrounding borehole, a first slip means mounted around said mandrel and engaging said first cone assembly and a second slip means mounted around said mandrel and engaging said second cone assembly.   
     
     
         13 . The bridge plug system according to  claim 12 , wherein said first ring member has a single radiused surface in contact with said first cone assembly, and
 wherein said second ring member has a single radiused surface in contact with said second cone assembly.   
     
     
         14 . The bridge plug system according to  claim 13 , wherein said first ring member has a single radiused surface in contact with said upper end of said sealing means, and
 wherein said second ring member has a single radiused surface in contact with said lower end of said sealing means.   
     
     
         15 . The bridge plug system according to  claim 14 , wherein said single radiused surface of said first ring member engages said double radiused surface of said upper end, and
 wherein said single radiused surface of said second ring member engages said double radiused surface of said lower end.   
     
     
         16 . The bridge plug system according to  claim 13 , wherein said sealing means has an inner cavity with an indentation between said upper end and said lower end. 
     
     
         17 . The bridge plug system according to  claim 16 , wherein said inner cavity is curved from said upper end to said indentation and from said lower end to said indentation. 
     
     
         18 . A method of installing a millable bridge plug system, comprising the steps of:
 placing a bridge plug in a wellbore, said wellbore having inner walls surrounding said bridge plug, said bridge plug comprising:
 a mandrel having an upper portion and a lower portion; 
 a sealing means positioned around the mandrel; 
 a plurality of ring members, a first ring member adjacent an upper end of said sealing means and a second ring member adjacent a lower end of said sealing means, wherein said upper end of said sealing means has a first means for resisting pressure when in contact with said first ring member, and wherein said lower end of said sealing means has a second means for resisting pressure when in contact with said second ring member; 
 a plurality of cone assemblies, a first cone assembly proximate to said first ring member and a second cone assembly proximate to said second ring member, said first ring member being between said first cone assembly and said sealing means, said second ring member being between said second cone assembly and said sealing means; and 
 a plurality of slip means for extending radially outward and engaging said inner walls, a first slip means mounted around said mandrel and engaging said first cone assembly and a second slip means mounted around said mandrel and engaging said second cone assembly; 
   forming a seal by exerting pressure on said bridge plug, said sealing member being compressed to radially extend outward to seal against said inner walls, said ring members pushing said sealing member to expand, said cone assemblies pushing said ring members; and   locking said bridge plug within said wellbore by exerting pressure, said cone assemblies pushing said slip means to extend radially outward to fixedly engage said inner walls, said bridge plug being locked in position within said wellbore.   
     
     
         19 . The bridge plug system according to  claim 18 , wherein said first means for resisting pressure is comprised of a double radiused surface,
 wherein said second means for resisting pressure is comprised of a double radiused surface,   wherein pressures are exerted by said ring members on said upper end and said lower end of said sealing means, and   wherein deformation of said sealing means is dependent upon location of said pressures on the double radiused surfaces of said upper end and said lower end of said sealing means.   
     
     
         20 . The bridge plug system according to  claim 18 , wherein said first means for resisting pressure is comprised of a surface interface with a curvature,
 wherein said second means for resisting pressure is comprised of a surface interface with a curvature,   wherein pressures are exerted by said ring members on said upper end and said lower end of said sealing means, and   wherein deformation of said sealing means is dependent upon location of said pressures on the curvatures of said upper end and said lower end of said sealing means.