Isolation member and isolation member seat for fracturing subsurface geologic formations

Abstract

An embodiment of an assembly includes an isolation member and an isolation member seat to together isolate a first portion of a well casing from a second portion of the well casing. The isolation member comprises an exterior surface including at least one of a ceramic material, metallic glass, a reactive metal or a PGA material, and the isolation member includes an interior chamber to receive an explosive device. The explosive device may be surrounded by a non-compressible fluid, and may include a pressure sensor, a processor, a battery and an explosive charge. The ceramic, metallic glass and reactive metal and may comprise one of zirconium oxide, aluminum oxide, Bulk metallic Glass, silicon nitride, tungsten carbide, reactive metal alloy or PGA salt. The isolation member is resistant to deformation within an isolation member seat under the application of a substantial pressure differential across the isolation member and isolation member seat. Detonation of the isolation member prevents the isolation member from presenting an obstruction to subsequent well operations.

What is claimed is: 
     
         1 . An assembly, including an isolation member and an isolation member seat, for securing in a tubular string within a well in the earth's crust to isolate a pressure within a first portion of the well from a pressure in a second portion of the well, the assembly comprising:
 an isolation member having an interior chamber and an exterior surface, including at least one of ceramic, metallic glass, reactive metal or polyclycolic acid, the isolation member including an exterior sealing surface;   an isolation member seat adapted for being secured in a well casing and having a sealing surface that is shaped to receive and to sealably engage with the exterior sealing surface of the isolation member;   at least one mechanical fuse element disposed intermediate the isolation member seat and the isolation member to secure the isolation member in an unseated position relative to the isolation member seat, the mechanical fuse element securing the isolation member in an unseated position with an open flow passage intermediate the sealing surface of the isolation member and the sealing surface of the isolation member seat;   a battery received within the interior chamber of the isolation member;   an explosive charge of an explosive material received within the interior chamber of the isolation member and conductively coupled to the battery;   a pressure sensor received within the interior chamber of the isolation member in fluid communication with an aperture extending from the exterior surface to the interior chamber; and   a processor received within the interior chamber and conductively coupled to receive an electrical current from the battery, conductively coupled to receive a signal from the pressure sensor, and conductively coupled to generate, after a predetermined time interval, a detonating current to detonate the explosive device in response to detecting a predetermined pressure sensed using the pressure sensor;   wherein after the isolation member seat is adapted for being secured within the well casing;   wherein the sealing surface on the isolation member and the sealing surface on the isolation member seat can sealably engage one with the other upon release of the isolation member from the unseated position resulting from the application of force to the isolation member and the one or more mechanical fuse elements due to a downward flow of well fluids at a rate sufficient to cause the one or more mechanical fuse elements to fail and release the isolation member; and   wherein detonation of the explosive charge fragments the isolation member to limit the size of debris in the well that may obstruct subsequent well operations and to increase a cumulative surface area of the isolation member to promote accelerated dissolution of a plurality of fragments.   
     
     
         2 . The assembly of  claim 1 , further comprising:
 one or more retainer members connected to the isolation member seat and positioned to prevent separation of the isolation member from the isolation member seat in the event of premature failure of the one or more mechanical fuse elements.   
     
     
         3 . The assembly of  claim 1 , wherein the explosive charge is formed with a recess to receive at least a portion of the battery; and
 wherein the recess in the explosive charge is shaped to prevent battery shielding of a portion of the isolation member upon detonation of the explosive charge.   
     
     
         4 . The assembly of  claim 1 , wherein the isolation member includes a plurality of separate portions coupled together form the isolation member. 
     
     
         5 . The isolation member of  claim 1 , wherein the exterior surface of the isolation member is comprised of at least one of a ceramic material, metallic glass, a reactive metal or polyclycolic acid. 
     
     
         6 . An assembly, including an isolation member and an isolation member seat, for securing in a tubular string within a well in the earth's crust to isolate a pressure within first portion of the well from a pressure in a second portion of the well, the assembly comprising:
 an isolation member having an interior chamber and an exterior surface, including at least one of ceramic, metallic glass, reactive metal or polyglycolic acid, the isolation member including an exterior sealing surface;   an isolation member seat adapted for being secured in a well casing and having a sealing surface that is shaped to receive and to sealably engage with the exterior sealing surface of the isolation member;   a cage connected to the isolation member seat to secure the isolation member within a space within the cage and to prevent unwanted separation between the isolation member and the isolation member seat;   a battery received within the interior chamber of the isolation member;   an explosive charge of an explosive material received within the interior chamber of the isolation member and conductively coupled to the battery;   a pressure sensor received within the interior chamber of the isolation member in fluid communication with an aperture extending from the exterior surface to the interior chamber; and   a processor received within the interior chamber and conductively coupled to receive an electrical current from the battery, conductively coupled to receive a signal from the pressure sensor, and conductively coupled to generate, after a predetermined time interval, a detonating current to detonate the explosive device in response to detecting a predetermined pressure sensed using the pressure sensor;   wherein after the isolation member seat is adapted for being secured within the well casing;   wherein the sealing surface on the isolation member and the sealing surface on the isolation member seat can sealably engage one with the other upon movement of the isolation member from the unseated position within the cage by the application of a force to the isolation member by a downward flow of well fluids at a rate sufficient to cause the isolation member to move downwardly within the cage and engage the isolation member seat; and   wherein detonation of the explosive charge fragments the isolation member to limit the size of debris in the well that may obstruct subsequent well operations and to increase a cumulative surface area of the isolation member to promote accelerated dissolution of a plurality of fragments.   
     
     
         7 . The assembly of  claim 6 , wherein the assembly further includes at least one mechanical fuse element disposed intermediate the isolation member seat and at least one of the cage and the isolation member to secure the isolation member in an unseated position relative to the isolation member seat, the mechanical fuse element securing the isolation member in an unseated position within the cage with an open flow passage intermediate the sealing surface of the isolation member and the sealing surface of the isolation member seat.