Single-Trip Deployment And Isolation Using Flapper Valve

Abstract

A downhole deployment and isolation system may be used to deploy a completion string, service the well, and isolate the lower completion string, optionally in a single trip. The lower completion string may be run into the well with a valve in an open condition, such as a flapper valve propped open by a mandrel. The mandrel may be operable to both disconnect the work string from the lower completion string and to close the valve upon disconnecting such as by removing the mandrel from the flapper. The valve may be remotely reopened with fluid pressure form surface.

What is claimed is: 
     
         1 . A deployment and isolation system, comprising:
 a connector for releasably connecting a work string with a lower completion string to deploy the lower completion string into a well, the connector including a mandrel operable to selectively disconnect the work string from the lower completion string;   a flapper valve coupled to the lower completion string and having a valve bore and a flapper initially propped open by an end of the mandrel while the flapper valve is coupled to the connector; and   wherein the mandrel is operable both to disconnect from the lower completion string and to remove the mandrel from the flapper valve for the flapper to close upon disconnection.   
     
     
         2 . The deployment and isolation system, further comprising:
 a valve remote reopening mechanism for remotely urging the flapper back to an open position in response to application of a threshold fluid pressure.   
     
     
         3 . The deployment and isolation system of  claim 2 , wherein the valve remote reopening mechanism further comprises:
 an actuator moveable from a retracted position to an extended position to urge the flapper from a closed position to an open position;   a spring biasing the actuator toward the extended position; and   one or more shear members for initially holding the actuator in the retracted position with the spring energized, the one or more shear members shearable in response to fluid pressure applied to the flapper in the closed position.   
     
     
         4 . The deployment and isolation system of  claim 1 , wherein the lower completion string comprises a frac string configured for delivering a stimulation fluid downhole through the flapper valve to one or more formation zones to be stimulated. 
     
     
         5 . The deployment and isolation system of  claim 1 , wherein the lower completion string comprises an inflow control device for controlling the flow of a plurality of formation fluids into the lower completion string and uphole through the flapper valve. 
     
     
         6 . The deployment and isolation system of  claim 1 , further comprising:
 a soft-release mechanism including an internal ball seat in a bore of the mandrel configured for capturing a drop ball to block flow through the mandrel bore, and a sleeve shiftable in response to fluid pressure applied above the captured drop ball.   
     
     
         7 . The deployment and isolation system of  claim 1 , further comprising:
 a pull-to-release mechanism in the connector for disconnecting the work string from the lower completion in response to an above-threshold tensile load.   
     
     
         8 . The deployment and isolation system of  claim 1 , further comprising:
 a rotate-to-release mechanism in the connector for disconnecting from the lower completion string upon rotation of the work string.   
     
     
         9 . A deployment and isolation system, comprising:
 a connector for releasably deploying a lower completion string into a well on a work string, the connector including a mandrel operable to selectively disconnect the work string from the lower completion string; and   a valve coupled to the lower completion string and having a valve closure element initially open while the work string is connected with the lower completion string, wherein the mandrel is operable to disconnect from the lower completion string and close the valve closure element upon disconnecting.   
     
     
         10 . The deployment and isolation system of  claim 9 , wherein the valve comprises one or both of a flapper valve and a ball valve, and a valve controller operable by the mandrel to selectively open or close the valve. 
     
     
         11 . A method of servicing and isolating a well in a single trip, comprising:
 deploying a lower completion string with a flapper valve into a well on a work string, with a flapper of the flapper valve propped open by a mandrel on a connector;   flowing a fluid through the mandrel and propped-open flapper; and   operating the mandrel to disconnect and retrieve the work string from the lower completion string with the flapper valve remaining downhole, thereby removing the mandrel from the flapper valve to allow the flapper to close.   
     
     
         12 . The method of  claim 11 , wherein the step of flowing a fluid comprises delivering a stimulation fluid downhole through the mandrel and propped-open flapper to the lower completion string to stimulate a formation zone. 
     
     
         13 . The method of  claim 11 , wherein the lower completion string comprises an inflow control device and the step of flowing a fluid comprises receiving a formation fluid separated through the inflow control device. 
     
     
         14 . The method of  claim 11 , further comprising:
 landing a final completion; and   subsequently applying a fluid pressure downhole to activate a valve remote reopening mechanism to urge the flapper back to an open position.   
     
     
         15 . The method of  claim 14 , wherein activating the valve reopening mechanism comprises:
 applying the fluid pressure to the closed flapper to shear a shear member;   releasing an actuator in response to shearing the shear member; and   biasing the released actuator from a retracted position to an extended position to urge the flapper from a closed position to an open position.   
     
     
         16 . The method of  claim 15 , further comprising:
 subsequently bleeding off the fluid pressure to the closed flapper until the biasing of the released actuator overcomes the fluid pressure to urge the flapper from the closed position to the open position.   
     
     
         17 . The method of  claim 11 , wherein flowing a fluid through the mandrel and propped-open flapper comprises delivering a stimulation fluid downhole through the flapper valve to one or more formation zones to be stimulated. 
     
     
         18 . The method of  claim 11 , wherein flowing a fluid through the mandrel and propped-open flapper comprises passing formation fluids through an inflow control device in the lower completion string and uphole through the flapper valve. 
     
     
         19 . The method of  claim 11 , wherein operating the mandrel to disconnect and retrieve the work string from the lower completion string comprises:
 capturing a drop ball to block flow through a bore of the mandrel;   applying a fluid pressure above the captured drop ball; and   shifting a sleeve in response to the applied fluid pressure.   
     
     
         20 . The method of  claim 11 , wherein operating the mandrel to disconnect and retrieve the work string from the lower completion string comprises a pull-to-release mechanism, a rotate-to-release mechanism, a soft-release mechanism, or combination thereof.