System and method for downhole operation using pressure activated and sleeve valve assembly

1. An isolation system for a subterranean well, comprising:

an isolation pipe, the isolation pipe being disposed within a base pipe, defining a volume between the base pipe and the isolation pipe;

a valve assembly coupled to the isolation pipe and comprising a pressure activated valve and a tool shiftable valve, the pressure activated valve being adapted to allow flow between the volume formed by the isolation pipe and the base pipe to an internal portion of the isolation pipe; and

wherein the valve assembly provides at least two independent flow paths in to and/or out of the isolation pipe.

2. The system of claim 1 , wherein the tool shiftable valve comprises a sliding sleeve shiftable between an opened position and a closed position.

3. The system of claim 2 , wherein the isolation pipe defines at least one port, and wherein the open position of the tool shiftable valve allows fluid flow through the port.

4. The system of claim 1 , wherein said pressure activated valve comprises:

an outer sleeve having at least one opening and an inner sleeve, the sleeves being movable relative to each other and configurable in at least locked-closed, unlocked-closed, and open configurations, wherein the inner sleeve covers the at least one opening in the locked-closed and unlocked-closed configurations and the inner sleeve does not cover the at least one opening in the open configuration; and

a pressure area on at least one of the sleeves, wherein a pressure acting on the pressure area configures the outer sleeve and inner sleeve between the locked-closed and unlocked-closed configurations.

5. The system of claim 4 , further comprising a lock between the inner sleeve and the outer sleeve that locks the inner sleeve and the outer sleeve in the locked-closed configuration.

6. The system of claim 4 , further comprising a spring member adapted to bias the inner sleeve relative to the outer sleeve so that the inner sleeve does not obstruct the at least one opening of the outer sleeve in the open configuration when the lock is released.

7. The system of claim 4 , wherein the inner sleeve comprises at least one opening that is selectively alignable with the at least one opening in the outer sleeve to allow fluid flow there through.

8. The system of claim 4 , further comprising a production screen, wherein fluid passing through the production screen is communicable with the pressure activated valve and the tool shiftable valve.

9. The method of claim 8 , wherein the production screen is wrapped around an outside of the valve assembly.

10. A method for isolating a production zone of a well, comprising:

inserting a pipe into the well, the pipe having a valve assembly comprising a pressure activated valve and a tool shiftable valve;

shifting the tool shiftable valve while the valve assembly is disposed in the well;

then opening the pressure activated valve by pressurized fluid acting on the pressure activated valve; and

allowing production fluid to flow through the pressure activated valve, the tool shiftable valve, or a combination thereof.

11. The method of claim 10 , further comprising performing a gravel pack operation on the well while the tool shiftable valve is open and the pressure activated valve is closed.

12. The method of claim 10 , wherein the pipe comprises an isolation string.

13. The method of claim 10 , wherein the tool shiftable valve is shiftable from at least an opened condition to a closed condition.

14. The method of claim 10 , wherein the pressure activated valve comprises an inner sleeve and an outer sleeve having at least one opening, the sleeves being movable relative to each other in at least two directions and initially secured relative to each other in at least one direction, wherein the opening of the pressure activated valve comprises:

applying a pressurized fluid to a pressure area on at least one of the sleeves to cause the sleeves to move relative to each other in a first direction;

reducing pressure to allow the sleeves to move relative to each other in a second direction;

at least partially uncovering the at least one opening to allow fluid flow therethrough.

15. The method of claim 14 , furthering comprising biasing the sleeves relative to each other with a spring member and allowing the sleeves to move relative to each other in the second direction with the spring member after reducing the pressure.

16. The system of claim 1 , wherein the isolation pipe is disposed below a formation packer.

17. The system of claim 1 , wherein the two independent flow paths are both capable of providing production fluid flow from the subterranean well.