Downhole apparatus

1. A downhole apparatus comprising:

a base pipe; and

a plurality of non-concentric pressure deformable chambers mounted externally thereon,

wherein the chambers extend axially along the pipe,

the chambers being inflatable to provide support for elements to be radially translated into contact with a surrounding wall, and with the chambers inflated and the elements in contact with the wall, the apparatus defining a fluid flow path to permit fluid to flow from a surrounding fluid-bearing formation into or along the base pipe.

2. The apparatus of claim 1 , wherein at least some of the chambers are spaced apart.

3. The apparatus of claim 1 , wherein at least some of the chambers are directly adjacent one another.

4. The apparatus of claim 1 , wherein at least some of the chambers abut.

5. The apparatus of claim 1 , wherein the chambers are configured to be capable of providing an excess degree of diametric expansion.

6. The apparatus of claim 1 , wherein the chambers are configured to be capable of providing a degree of expansion beyond that required to obtain contact with a surrounding wall.

7. The apparatus of claim 1 , wherein the chambers comprise metal-walled members.

8. The apparatus of claim 7 , wherein the members fit snugly around the base pipe.

9. The apparatus of claim 7 , wherein the members are spaced apart.

10. The apparatus of claim 7 , wherein the members are spaced apart and the spacing between the members varies.

11. The apparatus of claim 1 , wherein the chambers comprise hollow members.

12. The apparatus of claim 11 , wherein the chambers comprise steel tubes.

13. The apparatus of claim 1 , wherein the chambers comprise members cooperating with the base pipe.

14. The apparatus of claim 13 , wherein at least one chamber is at least partially defined by an arcuate elongate member.

15. The apparatus of claim 1 , further comprising a valve arrangement for controlling the flow of fluid into or from the chambers.

16. The apparatus of claim 15 , wherein the valve arrangement comprises a one-way valve.

17. The apparatus of claim 16 , wherein the one-way valve allows fluid to flow into the chamber.

18. The apparatus of claim 16 , wherein the one-way valve allows fluid to flow out of the chamber.

19. The apparatus of claim 15 , wherein the valve arrangement is configured to open on experiencing a predetermined pressure.

20. The apparatus of claim 15 , wherein the valve arrangement is configured to permit a degree of deflation of the chambers on the material within the chamber experiencing an applied pressure in response to a surrounding bore wall applying a predetermined load to the apparatus.

21. The apparatus of claim 1 , wherein the chambers are adapted to assume a deformed inflated configuration on exposure to an inflating pressure and are further adapted to retain the inflated configuration in the absence of the inflating pressure.

22. The apparatus of claim 1 , wherein a fluid passage is provided between the base pipe interior and at least one chamber.

23. The apparatus of claim 22 , wherein at least one fluid passage features a restriction.

24. The apparatus of claim 1 , wherein at least two fluid passages are provided between the base pipe interior and at least one chamber.

25. The apparatus of claim 1 , wherein a fluid passage is provided between at least one chamber and the exterior of the base pipe.

26. The apparatus of claim 1 , wherein the apparatus includes a sand control element.

27. The apparatus of claim 26 , wherein the sand control element comprises a filter screen.

28. The apparatus of claim 26 , wherein the sand control element is located externally of the chambers.

29. The apparatus of claim 26 , wherein the chambers support the sand control element.

30. The apparatus of claim 26 , further comprising an external shroud and wherein the external shroud protects the sand control element.

31. The apparatus of claim 26 , wherein the sand control element and chambers are configured such that reservoir fluids flow around the chambers and enter the base-pipe through openings in the base pipe.

32. The apparatus of claim 1 , wherein the fluid flow path extends through or around the chambers.

33. The apparatus of claim 1 , wherein the base pipe is apertured to permit passage of fluid.

34. The apparatus of claim 1 , wherein adjacent chambers are contacting and the contacting chambers are configured to permit fluid flow between the chambers.

35. The apparatus of claim 1 , including an inflow-controlling device incorporated in a flow path for reservoir fluids defined between the wellbore and the base pipe.

36. The apparatus of claim 1 , comprising a sealing element.

37. The apparatus of claim 1 , further comprising gripping members for gripping a surrounding bore wall.

38. The apparatus of claim 1 , comprising both a sealing element and gripping members.

39. The apparatus of claim 1 , further comprising at least one control line.

40. The apparatus of claim 39 , wherein at least one control line is mounted over a chamber.

41. A downhole apparatus comprising:

a base pipe;

a plurality of non-concentric pressure deformable chambers mounted externally on the base pipe; and

a sand control element mounted externally of the chambers,

wherein with the chambers inflated and deformed to assume an extended configuration the apparatus defines a fluid path to permit fluid to flow from a surrounding fluid-bearing formation into or along the base pipe.

42. A method of lining a bore, the method comprising:

providing downhole apparatus comprising a base pipe, a plurality of non-concentric fluid pressure deformable chambers mounted externally thereon, and a sand control element mounted externally of the chambers;

locating the apparatus in a well bore intersecting a fluid-bearing formation; and

inflating and deforming at least one of the chambers to increase the diameter described by the sand control element such that with the chambers inflated the apparatus defines a fluid flow path permitting fluid to flow from the surrounding fluid-bearing formation into or along the base pipe.