Selective isolation of surface controlled gas lift valve

Abstract

A surface controlled flow control valve (“SCFCV”) used in a wellbore is protected from potentially damaging substances by adding a temporary plug that blocks communication between the substances and the valve. Potentially damaging substances include corrosive fluids, fluids with entrained particles, cement, or other substances that harden over time. The types of SCFCV valves include gas lift valves and inflow control valves. The plug is made from a material that is initially cohesive and blocks the substance from contacting the valve. But after a designated period of time, the material degrades and is no longer sufficiently cohesive to act as a barrier and shield the valve from the substance. Before the designated time expires, wellbore procedures involving flowing the substance in the wellbore are completed, and the wellbore is flushed before the valve operation resumes.

What is claimed is: 
     
         1 . A method of wellbore operations comprising:
 producing fluid from a wellbore through production tubing that is disposed in the wellbore;   injecting lift gas into the production tubing through a port formed on a sidewall of the production tubing;   adding a substance into the production tubing that is present in the production tubing for a designated period of time; and   shielding the port from the substance for at least the designated period of time.   
     
     
         2 . The method of  claim 1 , wherein the step of shielding comprises forming a barrier with a material that remains cohesive for the designated period of time and dissolves after the designated period of time. 
     
     
         3 . The method of  claim 1 , wherein the step of shielding comprises forming a barrier with an insert having a pressure actuated valve, and actuating the valve after the designated period of time by adjusting pressure outside the production tubing. 
     
     
         4 . The method of  claim 1 , wherein the step of adding occurs during an operation selected from the group consisting of cementing, fracturing, proppant injection, acidizing, and chemical injection. 
     
     
         5 . The method of  claim 1 , wherein the lift gas is injected into the production tubing through a surface controlled flow control valve (“SCFCV”) that is attached to the production tubing. 
     
     
         6 . The method of  claim 5 , wherein the SCFCV is susceptible to damage when exposed to the substance. 
     
     
         7 . The method of  claim 1 , wherein the material is configured into a plug and retained inside the production tubing adjacent the port. 
     
     
         8 . The method of  claim 1 , wherein the substance comprises a first substance, the method further comprising injecting a second substance into the production tubing after the designated period of time. 
     
     
         9 . The method of  claim 1 , further comprising injecting lift gas into the production tubing after the designated period of time. 
     
     
         10 . The method of  claim 1 , wherein the port is located in a side pocket mandrel of the production tubing. 
     
     
         11 . The method of  claim 10 , wherein the side pocket mandrel is formed in an enlarged diameter portion of the production tubing, the side pocket mandrel comprising a planar skirt that extends axially inside the production tubing with lateral edges attached to inner sidewalls of the production tubing to form a cylinder, wherein upper and lower ends of the cylinder are open to a bore in the production tubing. 
     
     
         12 . The method of  claim 11 , wherein the material is formed into a plug and installed in the cylinder at a location in a flow path between a side port formed through the skirt and the inlet port. 
     
     
         13 . The method of  claim 12 , wherein an insert is disposed above the plug, and wherein the insert is moveable into the flow path. 
     
     
         14 . A method of wellbore operations comprising:
 flowing a produced fluid in a bore of a tubular disposed in a wellbore;   injecting a secondary fluid into the tubular that mixes with the produced fluid;   controlling injection of the secondary fluid with a valve that is coupled to the tubular;   introducing a substance into the tubular that is in the tubular for a designated period of time; and   shielding the valve from the substance for at least the designated period of time.   
     
     
         15 . The method of  claim 14 , wherein the step of shielding comprises forming a barrier to communication of the substance with the valve by adding a material between the bore and the valve, wherein the material remains cohesive for the designated period of time, and after the designated period of time, the material degrades into a non-cohesive state to remove the barrier. 
     
     
         16 . The method of  claim 15 , wherein the tubular comprises production tubing having a side pocket mandrel, wherein the valve is in communication with the bore through a port formed through a sidewall of the side pocket mandrel, wherein the material is formed into a plug that is inserted into a cylinder formed in the side pocket mandrel. 
     
     
         17 . The method of  claim 16 , wherein the substance comprises wellbore cement that is injected into the bore on surface, the method further comprising purging the cement from the bore and repeating the steps of flowing and injecting. 
     
     
         18 . A system for use in wellbore operations comprising:
 a wellhead assembly mounted over a wellbore;   a tubular in the wellbore in communication with the wellhead assembly;   a valve coupled with the tubular;   a flow path between a bore in the tubular and the valve; and   a plug in the flow path comprising a material that over time changes from being cohesive and forming a barrier to fluid communication along the flow path to a degraded state and allows fluid communication along the flow path.   
     
     
         19 . The system of  claim 18 , wherein the tubular comprises production tubing, wherein the valve is a surface controlled flow control valve and is configured to control flow from an annulus formed around the production tubing to the bore, wherein the plug is disposed in a cylinder formed in a side pocket mandrel of the production tubing. 
     
     
         20 . The system of  claim 19 , wherein the cylinder extends axially in the side pocket mandrel and has sidewalls radially intersected by a side port and an inlet port, wherein the cylinder is in selective communication with the bore through the side port, and is in selective communication with an exit of the valve through the inlet port, and wherein the plug is a barrier to flow between the side port and the inlet port.