Well isolation

1. A system for isolating a wellbore having a fluid flow passage extending from surface to a subterranean location, the system comprising:

a first, downhole, valve member configured for location in the wellbore at a first subterranean location and moveable between a first configuration which permits access through the flow passage and a second configuration which isolates the flow passage below the valve member;

a second, uphole, valve member configured for location in the wellbore at a second subterranean location spaced from the first valve member and moveable between a first configuration which permits access through the second valve member and a second configuration which provides an isolated volume between the first and second valve members;

a monitoring arrangement for obtaining information relating to a condition in the isolated volume; and

a communication arrangement for communicating the information relating to the condition in the isolated volume to a remote location,

wherein the communication arrangement is configured to transmit or otherwise relay the information relating to the condition in the isolated volume to the remote location via at least one intermediate location.

2. The system of claim 1 , wherein at least part of the monitoring arrangement is configured for location in the isolated volume between the first valve member and the second valve member.

3. The system of claim 1 , wherein at least one of:

at least part of the communication arrangement is configured for location in the isolated volume between the first valve member and the second valve member; and

at least part of the communication arrangement is configured for location outwith the isolated volume between the first valve member and the second valve member.

4. The system of claim 1 , wherein at least one of:

the monitoring arrangement is configured to obtain information relating to the integrity of the isolation;

the monitoring arrangement comprises a sensor; and

the monitoring arrangement comprises a pressure sensor.

5. The system of claim 1 , comprising a memory device for storing the information obtained by the monitoring arrangement.

6. The system of claim 1 , wherein the communication arrangement comprises at least one of: a wireless communication arrangement; an acoustic communication arrangement; a wired communication arrangement; an electric line communication arrangement; an optical communication arrangement; a waveguide communication arrangement; and an optical fiber.

7. The system of claim 1 , comprising a power supply, the power supply comprising one of: a battery; a battery pack; an alkaline battery; and an alkaline battery pack.

8. The system of claim 1 , wherein the at least one intermediate location comprises a first intermediate location and the system comprises a first receiver/transmitter or transceiver disposed at the first intermediate location.

9. The system of claim 8 , wherein the first receiver/transmitter or transceiver is located at a subterranean location in the wellbore.

10. The system of claim 1 , wherein the at least one intermediate location comprises a second intermediate location and the system comprises a second receiver/transmitter or transceiver disposed at the second intermediate location.

11. The system of claim 10 , wherein the second receiver/transmitter or transceiver is located at a subsurface location or on the seabed.

12. The system of claim 1 , wherein the communication arrangement is configured to relay the information relating to the condition in the isolated volume at a given time interval.

13. The system of claim 1 , wherein the communication arrangement is configured to receive information or commands.

14. The system of claim 1 , comprising a body for running the first and second valve members into the wellbore.

15. The system of claim 1 , wherein at least one of the first valve member and the second valve member comprises a ball valve.

16. The system of claim 14 , comprising a seal member for sealing an annulus between the body and a wall of the flow passage.

17. A method for isolating a wellbore having a flow passage extending from surface to a subterranean location, the method comprising:

locating a first, downhole, valve member at a first subterranean location in a wellbore;

locating a second, uphole, valve member at a second subterranean location in the wellbore spaced from the first valve member;

moving the first valve member between a first configuration which permits access through the flow passage to a second configuration which isolates the flow passage below the valve member;

moving the second valve member between a first configuration which permits access through the second valve member and a second configuration which provides an isolated volume between the first and second valve members;

obtaining information relating to a condition in the isolated volume; and

communicating the information relating to the condition in the isolated volume to a remote location via at least one intermediate location.

18. The method of claim 17 , wherein the first valve member and the second valve member are located in the bore in a single trip.

19. The method of claim 17 , comprising at least one of:

performing an integrity test on the first valve member by applying a pressure above and/or below the first valve member to pressure test the integrity of the first valve member; and

performing an integrity test on the second valve member by monitoring the pressure across the second valve member.

20. The system of claim 1 , wherein the monitoring arrangement, or part of the monitoring arrangement, is configured for location outwith the isolated volume between the first valve member and the second valve member.