Multi-stage hydraulic fracturing tool and system with releasable engagement

Abstract

The invention relates to a multi-stage hydraulic fracturing tool and system for controllably exposing selected locations along a wellbore to a pressurized fluid. The system includes a casing having one or more ports, one or more actuation members which travel down a borehole, and one or more sliding sleeves which initially cover some of the ports and are movable using a mating actuation member to uncover those ports. The system further includes a stop mechanism to contact the sliding sleeve member after the sliding sleeve member has moved a first distance downhole under a first predefined amount of force, and a release mechanism to cause the actuation member to disengage from the sliding sleeve member release under a second predetermined amount of force.

We claim: 
     
         1 . A system for controllably exposing selected locations along a wellbore to a pressurized fluid, the wellbore including an elongated casing disposed therein, the casing defining an internal borehole extending longitudinally with the wellbore, the casing having one or more ports extending through the casing, the system comprising:
 an actuation member configured for travelling down the borehole in a longitudinal direction;   a first sliding sleeve member for disposal within the borehole and having an aperture for receiving the actuation member therein, the first sliding sleeve member configured to initially cover one of the one or more ports, and further configured to move downhole in response to a predetermined amount of force in the longitudinal direction to uncover the port;   wherein the actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the first sliding sleeve member to allow for the predetermined amount of force to be transferred from the actuation member to the first sliding sleeve member; and   a stopping member affixed to the casing downhole of the first sliding sleeve member, the stopping member configured to contact the first sliding sleeve member after the first sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the first sliding sleeve member, the stopping member configured to release under a second predetermined amount of force to allow said further downhole travel of the first sliding sleeve member;   wherein the first engagement portion and the second engagement portion are configured to release from one another upon said further downhole travel of the first sliding sleeve member under said second predetermined amount of force, to cause the actuation member to disengage from the first sliding sleeve member.   
     
     
         2 . The system of  claim 1 , wherein the first engagement portion of the actuation member comprises a wedged portion and a groove formed at least partially circumferentially around an outer surface of the actuation member, and
 the first engagement portion of the first sliding sleeve member comprises one or more inward-facing protrusions connected to the first sliding sleeve member, and protruding radially into the aperture, one or both of the protrusions and the groove configured, upon alignment of the protrusions and the groove, to move radially toward the other due to a biasing force so that the protrusions are received within the groove, whereupon the predetermined amount of force is transferred from the actuation member to the first sliding sleeve member.   
     
     
         3 . The system of  claim 2 , wherein one or both of the actuation member and the first sliding sleeve member have a deformation region. 
     
     
         4 . The system of  claim 2 , wherein the actuation member has a deformation region comprising the groove disposed thereon; wherein the biasing force is generated by resilient radial inward deformation of the deformation region, said resilient radial inward deformation occurring in response to action of the wedged portion on the inward-facing protrusions during downhole motion of the actuation member past the inward-facing protrusions. 
     
     
         5 . The system of  claim 3 , wherein downhole of the stopping member, the borehole or casing has a narrowing portion configured to contact and apply force on the wedged portion of the actuation member due to said further downhole travel, said force causing a second instance of radial inward deformation of the deformation region to release the inward-facing protrusions from the groove, to cause the actuation member to disengage from the first sliding sleeve member. 
     
     
         6 . The system of  claim 3 , wherein downhole of the stopping member the casing comprises a wedge-shaped body configured to contact to and apply force on the wedged portion of the actuation member due to said further downhole travel, said force causing a second instance of radial inward deformation of the deformation region to release the inward-facing protrusions from the groove, to cause the actuation member to disengage from the first sliding sleeve member. 
     
     
         7 . The system  claim 1 , further comprising:
 a second sliding sleeve member for disposal within the borehole uphole of the first sliding sleeve member, the second sliding sleeve member having a second aperture for receiving the actuation member therein, the second sliding sleeve member initially covering a second port of the one or more ports extending through the casing and configured, upon application of a second predetermined amount of force applied in the longitudinal direction, to move downhole in the longitudinal direction, thereby uncovering the second port;   a second stopping member affixed to the casing downhole of the second sliding sleeve member, the second stopping member configured to contact the second sliding sleeve member after the second sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the second sliding sleeve member, the second stopping member configured to release under another predetermined amount of force to allow said further downhole travel of the second sliding sleeve member;   wherein the second sliding sleeve member comprises an engagement portion configured to matingly engage the first engagement portion of the actuation member, to allow for the predetermined amount of force to be transferred from the actuation member to the second sliding sleeve member;   wherein the first engagement portion and the engagement portion of the second sliding sleeve member are configured to release from one another upon said further downhole travel of the second sliding sleeve member under said second predetermined amount of force, to cause the actuation member to disengage from the second sliding sleeve member.   
     
     
         8 . The system of  claim 2 , wherein the wedged portion is located along a leading edge of the actuation member. 
     
     
         9 . The system of  claim 2 , wherein the wedged portion protrudes from the outer surface of the actuation member at a location between a leading edge and a trailing edge of the actuation member. 
     
     
         10 . The system of  claim 1 , wherein the actuation member the actuation member initially substantially fills the borehole and travels down the borehole in response to hydraulic pressure applied uphole of the actuation member. 
     
     
         11 . The system of  claim 1 , wherein the actuation member includes a longitudinal aperture extending from an uphole face of the actuation member to a downhole face of the actuation member, and a plug member seat within the longitudinal aperture, the plug member seat configured for receiving and retaining a plug member for blocking the longitudinal aperture. 
     
     
         12 . The system of  claim 11 , wherein the plug member is controllably dissolvable. 
     
     
         13 . The system of  claim 2 , wherein the actuation member includes a leading portion and a trailing portion, the leading portion located downhole of the trailing portion, and wherein the trailing portion is compressible radially inwardly due to force applied by the one or more inward-facing protrusions on the wedged portion when the actuation member moves downhole past the one or more inward-facing protrusions. 
     
     
         14 . The system of  claim 13 , wherein the trailing portion comprises resiliently deformable collets actuated for radially inward compression. 
     
     
         15 . A system for controllably exposing selected locations along a wellbore to a pressurized fluid, the wellbore including an elongated casing disposed therein, the casing defining an internal borehole extending longitudinally with the wellbore, the casing having one or more ports extending through the casing, the system comprising:
 an actuation member configured for travelling down the borehole in a longitudinal direction;   at least one sliding sleeve member for disposal within the borehole and each having an aperture for receiving the actuation member therein, the at least one sliding sleeve member configured to initially cover a respective port, and further configured to move downhole in response to a predetermined amount of force in the longitudinal direction to uncover the port;   wherein the actuation member comprises a first engagement portion configured to matingly engage with a corresponding second engagement portion of the at least one sliding sleeve member to allow for the predetermined amount of force to be transferred from the actuation member to the at least one sliding sleeve member;   a stopping member affixed to the casing downhole of one or more of the at least one sliding sleeve member, the stopping member configured to contact the at least one sliding sleeve member after the at least one sliding sleeve member has moved a first distance downhole and initially inhibit further downhole travel of the at least one sliding sleeve member, the stopping member configured to release under a second predetermined amount of force to allow said further downhole travel of the at least one sliding sleeve member;   wherein the first engagement portion and the second engagement portion are configured to release from one another upon said further downhole travel of the at least one sliding sleeve member under said second predetermined amount of force, to cause the actuation member to disengage from the at least one sliding sleeve member.   
     
     
         16 . The system of  claim 15 , wherein the stopping member is affixed to the casing downhole of each of the at least one sliding sleeve member.