Nitinol Spring Through Tubing Bridge Plug

Abstract

A bridge plug assembly that can be set in a wellbore tubular using wellbore pressure to form a pressure differential on a piston that actuates sliding members. A resilient member, such as a spring, is compressed from a downhole pressure differential. The bridge plug assembly can be removed by equalizing pressure across the piston and the spring. The spring can expand and re-stow the expanded plug. The plug can be formed from a nickel titanium alloy flexible member that can be selectively radially expanded so its outer surface sealingly engages a surrounding tubular. The percentage of weight of nickel can range up to about 40 to about 58%, 55% or to about 60%.

1 . A bridge plug assembly for plugging a tubular within a wellbore comprising:
 an elongate mandrel;   an actuation sleeve circumscribing the mandrel;   a first reservoir within the actuation sleeve;   a plug section on the mandrel and adjacent the actuation sleeve and selectively moveable from a substantially cylindrical insertion configuration to a radially bulging plugging configuration;   a second reservoir disposed between the first reservoir and the plug section; and   a sealing barrier between the first and second reservoir and coupled to the actuation sleeve, so that when pressure in the first reservoir exceeds the second reservoir, the barrier is urged into the second reservoir and the actuation sleeve is urged into compressive engagement with the plug section to move the plug section to the radially bulging plugging configuration.   
     
     
         2 . The bridge plug of  claim 1 , further comprising a selectively open and closed valve having an end in fluid communication with the wellbore and an opposite end in fluid communication with the first reservoir. 
     
     
         3 . The bridge plug of  claim 1 , further comprising a selectively open and closed valve having an end in fluid communication with the wellbore and an opposite end in fluid communication with the second reservoir. 
     
     
         4 . The bridge plug of  claim 1 , further comprising a flow circuit in the mandrel made up of axial and radial passages that interconnect and a valve actuator coupled with the mandrel that selectively provides fluid communication between the flow circuit and the second reservoir. 
     
     
         5 . The bridge plug of  claim 1 , further comprising a flow circuit in the mandrel made up of axial and radial passages that interconnect and a valve actuator coupled with the mandrel that selectively provides fluid communication between the first reservoir and the second reservoir. 
     
     
         6 . The bridge plug of  claim 1 , further comprising a deployment module attachable to an end of the actuation sleeve. 
     
     
         7 . The bridge plug of  claim 1 , further comprising a spring coaxially disposed in the mandrel and selectively compressible, so that when fluid pressure across the barrier is equalized, the spring axially expands and selectively moves the plug section to the substantially cylindrical insertion configuration. 
     
     
         8 . The bridge plug of  claim 1 , further comprising an outer shell on the outer periphery of the plug section comprising a nickel titanium alloy. 
     
     
         9 . A method of plugging a tubular within a wellbore comprising:
 providing in the tubular a bridge plug assembly having a mandrel, an actuation sleeve circumscribing the mandrel, and adjacent the sleeve a plug element on the mandrel that is selectively configurable between a substantially cylindrical configuration to a bulbous configuration; and   axially urging the actuation sleeve against the plug element by directing pressure from the wellbore along the axis of the bridge plug assembly so that the plug element changes from the substantially cylindrical configuration into the bulbous configuration to plug the tubular.   
     
     
         10 . The method of  claim 9 , wherein the bridge plug assembly further comprises a reservoir and a piston axially slidable into the reservoir and that is coupled with the actuation sleeve. 
     
     
         11 . The method of  claim 9 , wherein the bridge plug assembly further comprises a resilient member axially disposed in the mandrel, the method further comprising compressing the spring by forming a pressure differential along the spring. 
     
     
         12 . The method of  claim 11 , further comprising removing the pressure differential along the spring so that the spring exerts a force to expand and directing the spring force across the plug element so that the plug element returns to the substantially cylindrical configuration from the bulbous configuration. 
     
     
         13 . The method of  claim 9 , wherein the plug element comprises an outer shell formed from a nickel titanium alloy. 
     
     
         14 . The method of  claim 9 , wherein the plug element comprises an outer shell formed from an elastomer. 
     
     
         15 . The method of  claim 9 , wherein a flow circuit is provided in the mandrel and made up of axial and radial passages that interconnect and a valve actuator coupled with the mandrel that selectively provides fluid communication between the first reservoir and the second reservoir, the method further comprising actuating the valve actuator to provide fluid communication between the first and second reservoirs. 
     
     
         16 . The method of  claim 9 , wherein the bridge plug assembly further comprises a flow circuit in the mandrel made up of axial and radial passages that interconnect and a valve actuator coupled with the mandrel that selectively provides fluid communication between the flow circuit and the second reservoir, the method further comprising actuating the valve actuator to provide fluid communication between the flow circuit and the second reservoir. 
     
     
         17 . The method of  claim 9 , wherein the bridge plug assembly further comprises an actuation module, the method further comprising removing the actuation module from the bridge plug assembly. 
     
     
         18 . The method of  claim 17 , the method further comprising reattaching the actuation module to the bridge plug assembly, actuating a valve in the bridge plug assembly to equalize pressure to the actuation sleeve, and moving the plug element so that the plug element changes to the substantially cylindrical configuration from the bulbous configuration, and removing the bridge plug assembly from the tubular. 
     
     
         19 . The method of  claim 17 , wherein the step of moving the plug element so that the plug element changes to the substantially cylindrical configuration from the bulbous configuration comprising compressing a spring within the mandrel with a pressure differential, then removing the pressure differential along the spring so that the spring exerts a force to expand and directing the spring force across the plug element so that the plug element returns to the substantially cylindrical configuration from the bulbous configuration.