Sacrificial isolation ball for fracturing subsurface geologic formations

Abstract

An embodiment of a fracking ball cooperates with a ball seat to isolate a well first portion of an earthen well drilled into the earth's crust from a well second portion and comprises an interior chamber to receive an explosive charge. The explosive charge may be surrounded by a filler material that is resistant to deformation. A pressure sensor, a circuit, and a battery are also received into the chamber. The ball material, may comprise one of zirconium oxide, aluminum oxide, bulk metallic glass, silicon nitride or tungsten carbide, and the ball is resistant to deformation within the ball seat under the application of a substantial pressure differential across the ball and ball seat. Detonation of the explosive charge fragments the ball to prevent the ball from presenting an obstruction to subsequent well operations. A safety fuse may be included to enable safe handling and transport.

What is claimed is: 
     
         1 . A ball for use with a ball seat set in a tubular string within a well drilled into 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 ball comprising:
 a spherical body of a solid material and having an interior chamber and an exterior surface to engage the ball seat;   a battery received within the interior chamber of the body;   an explosive charge including an explosive material received within the interior chamber of the body and coupled for detonation by the battery;   a pressure sensor received within the interior chamber of the body in fluid communication with an aperture extending from the exterior surface of the spherical body to the interior chamber of the spherical body; and   a circuit 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 charge in response to detecting a predetermined pressure sensed using the pressure sensor;   wherein detonation of the explosive charge fragments the spherical body to limit the size of spherical body fragments present in the well.   
     
     
         2 . The ball of  claim 1 , wherein the solid material of the spherical body is a material, that is at least in part dissolvable in one or more fluids introduced into the well. 
     
     
         3 . The ball of  claim 1 , wherein the spherical body includes a plurality of spherical body portions that are assembled and secured together to form the spherical body. 
     
     
         4 . The ball of  claim 3 , wherein the plurality of spherical body portions includes two hemispherical body portions. 
     
     
         5 . The ball of  claim 4 , wherein the plurality of spherical body portions are securable together using an epoxy adhesive. 
     
     
         6 . The ball of  claim 1 , wherein the solid material of the spherical body comprises at least one of: zirconium oxide, silicon nitride, tungsten carbide, zirconia toughened alumina, bulk metallic glass and aluminum oxide. 
     
     
         7 . The ball of  claim 1 , wherein the ball further comprises;
 a filler material disposed within the hollow interior of the ball.   
     
     
         8 . The ball of  claim 7 , wherein the filler material includes at least one of sand, gel, ceramic beads and an incompressible fluid. 
     
     
         9 . The ball of  claim 1 , further comprising a fuse aperture in the spherical body for receiving a safety fuse;
 wherein the safety fuse enables the detonation of the explosive charge by current provided from the battery.   
     
     
         10 . A ball for landing within a ball seat set in a tubular string to isolate a first portion of a well drilled into the earth's crust from a second portion of the well, the ball, comprising:
 a spherical body of a solid material having an exterior surface to engage the ball seat and an interior chamber;   a battery received within the interior chamber;   an explosive charge received within the interior chamber and coupled for detonation by an electrical current from the battery;   a pressure sensor received within the interior chamber and in fluid communication with an aperture extending from the exterior surface to the interior chamber; and   a circuit received within the interior chamber to receive a signal from the pressure sensor upon detection by the pressure sensor of a predetermined pressure and to generate a detonation signal from the battery to the explosive charge at a predetermined time interval after the detection of the predetermined pressure by the pressure sensor;   wherein detonation of the explosive charge fragments the ball.   
     
     
         11 . The ball of  claim 10 , wherein the solid material of the spherical body is at least in part dissolvable in one or more fluids introduced into the well. 
     
     
         12 . The ball of  claim 10 , wherein the spherical body includes a plurality of assembled spherical body portions secured together to form the spherical body. 
     
     
         13 . The ball of  claim 12 , wherein the plurality of spherical body portions includes two hemispherical body portions. 
     
     
         14 . The ball of  claim 13 , wherein the plurality of spherical body portions are securable together using an epoxy adhesive. 
     
     
         15 . The ball of  claim 10 , wherein the solid material of the spherical body comprises at least one of: zirconium oxide, silicon nitride, tungsten carbide, zirconia toughened alumina, bulk metallic glass and aluminum oxide. 
     
     
         16 . The ball of  claim 10 , wherein the ball further comprises:
 a filler material disposed within the hollow interior of the ball.   
     
     
         17 . The ball of  claim 16 , wherein the filler material includes at least one of sand, gel, ceramic beads and an incompressible fluid. 
     
     
         18 . The ball of  claim 10 , further comprising a fuse aperture in the spherical body for receiving a safety fuse;
 wherein the safety fuse enables the detonation of the explosive charge by current provided from the battery.