Downhole Apparatus

1 . Downhole apparatus comprising a base pipe and a plurality of non-concentric pressure deformable chambers mounted externally thereon.

2 . The apparatus of claim 1 , wherein the chambers extend axially along the base pipe.

3 . The apparatus of claim 1 or 2 , wherein the chambers extend circumferentially around the base pipe.

4 . The apparatus of claim 1 , 2 or 3 , wherein at least some of the chambers are spaced apart.

5 . The apparatus of any preceding claim, wherein at least some of the chambers are directly adjacent one another.

6 . The apparatus of any preceding claim, wherein at least some of the chambers abut.

7 . The apparatus of any preceding claim, wherein at least some of the chambers overlap.

8 . The apparatus of claim 7 , wherein overlapping portions of the chamber are formed such that the chambers collectively describe a substantially circular form.

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

10 . The apparatus of any preceding claim, wherein the chambers provide support for elements intended to be radially translated into contact with a surrounding wall.

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

12 . The apparatus of any preceding claim, wherein the chambers comprise metal-walled members.

13 . The apparatus of any preceding claim, wherein the chambers comprise hollow members.

14 . The apparatus of claim 13 , wherein the chambers comprise steel tubes.

15 . The apparatus of any of claims 12 to 14 , wherein the members fit snugly around the base pipe.

16 . The apparatus of any of claims 12 to 15 , wherein the members are spaced apart.

17 . The apparatus of any of claims 12 to 16 , wherein the spacing of the members varies.

18 . The apparatus of any preceding claim, wherein walls of the chambers comprise living or plastic hinges.

19 . The apparatus of any preceding claim, wherein the chambers comprise members cooperating with the base pipe.

20 . The apparatus of claim 19 , wherein at least one chamber is at least partially defined by an arcuate elongate member.

21 . The apparatus of claim 20 , wherein said elongate member encircles the base pipe to create a ring-shaped chamber.

22 . The apparatus of claims 19 or 20 , wherein said elongate member extends axially along the base pipe.

23 . The apparatus of any preceding claim, comprising a valve arrangement for controlling the flow of fluid into or from the chambers.

24 . The apparatus of claim 23 , wherein the valve arrangement comprises a one-way valve.

25 . The apparatus of claim 24 , wherein the one-way valve allows fluid to flow into the chamber.

26 . The apparatus of claim 24 , wherein the one-way valve allows fluid to flow out of the chamber.

27 . The apparatus of any of claims 23 to 26 , wherein the valve arrangement is configured to open on experiencing a predetermined pressure.

28 . The apparatus of any of claims 23 to 27 , 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.

29 . The apparatus of any preceding claim, wherein the chambers are adapted to retain an inflated configuration in the absence of inflating pressure.

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

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

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

33 . The apparatus of any of claims 30 to 32 , wherein at least one fluid passage features a restriction.

34 . The apparatus of any preceding claim, wherein the apparatus includes a sand control element.

35 . The apparatus of claim 34 , wherein the sand control element comprises a filter screen.

36 . The apparatus of claim 34 or 35 , wherein the sand control element is located externally of the chambers.

37 . The apparatus of any of claims 34 to 36 , wherein the chambers support the sand control element.

38 . The apparatus of any of claims 34 to 37 , wherein an external shroud protects the sand control element.

39 . The apparatus of any of claims 34 to 38 , 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.

40 . The apparatus of any of claims 34 to 39 , wherein the sand control element and chambers are configured such that reservoir fluids flow through the chambers.

41 . The apparatus of any preceding claim, wherein the apparatus defines a fluid flow path to permit fluid to flow from a surrounding fluid-bearing formation into or along the base pipe.

42 . The apparatus of claim 41 , wherein the flow path extends through or around the chambers.

43 . The apparatus of any preceding claim, wherein the base pipe is apertured to permit passage of fluid.

44 . The apparatus of any preceding claim, wherein adjacent contacting chambers are configured to permit fluid flow between the chambers.

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

46 . The apparatus of any preceding claim, comprising a sealing element.

47 . The apparatus of claim 46 , wherein the sealing element is located externally of the chambers.

48 . The apparatus of claim 46 or 47 , wherein the sealing element is adapted to be supported by the chambers.

49 . The apparatus of any of claims 46 to 48 , wherein the sealing element comprises an elastomer.

50 . The apparatus of any preceding claim, further comprising gripping members for gripping a surrounding bore wall.

51 . The apparatus of claim 50 , wherein the gripping members are operatively associated with deformable chambers, whereby inflation of the chambers radially displaces the gripping members.

52 . The apparatus of any preceding claim, comprising both a sealing element and gripping members.

53 . The apparatus of any preceding claim, further comprising at least one control line.

54 . The apparatus of claim 53 , wherein the control line is at least one of a hydraulic control line, an electrical control line and an optical control line.

55 . The apparatus of claim 53 or 54 , wherein the control line extends axially of the base pipe.

56 . The apparatus of any of claims 53 to 55 , wherein at least one control line is mounted under a chamber.

57 . The apparatus of any of claims 53 to 56 , wherein at least one control line is mounted adjacent to a chamber.

58 . The apparatus of any of claims 53 to 57 , wherein at least one control line is mounted over a chamber.

59 . A method of lining a bore, the method comprising: providing downhole apparatus comprising a base pipe and a plurality of non-concentric fluid pressure deformable chambers mounted externally thereon; and inflating at least one of the chambers to increase the diameter described by the apparatus.

60 . The method of claim 59 , comprising providing a chamber in a first configuration, deforming a wall of the chamber from a first configuration to a second configuration, and then inflating the chamber to urge the walls to return towards the first configuration.

61 . The method of claim 59 or 60 , wherein changes in chamber form are achieved without substantially changing the length of the chamber wall.

62 . The method of any of claims 59 to 61 , comprising retaining material utilised to inflate the chambers in the chambers.

63 . The method of any of claims 59 to 62 , wherein material used to inflate the chambers subsequently hardens within the chambers.

64 . The method of claim 63 , wherein the hardened material is deformable.

65 . The method of any of claims 59 to 62 , comprising subsequently flowing material utilised to inflate the chambers from the chambers.

66 . The method of any of claims 59 to 65 , wherein the chambers are inflated by exposing the chambers to pipe pressure, while an external wall of the fluid chamber experiences lower annulus pressure.

67 . The method claim 66 , wherein a fluid is pumped into a string supporting the apparatus and in fluid communication with the chambers, flow of fluid from the string being restricted to create a fluid pressure differential.

68 . The method of any of claims 59 to 67 , comprising inflating chambers collectively.

69 . The method of any of claims 59 to 68 , comprising inflating chambers to a common pressure.

70 . The method of any of claims 59 to 69 , comprising inflating chambers individually.

71 . The method of any of claims 59 to 70 , comprising inflating chambers to different pressures.

72 . The method of any of claims 59 to 71 , comprising controlling the inflation pressure of chambers to control the pressure applied to a surrounding bore wall.

73 . The method of claim 72 , comprising applying different pressure forces to different bore wall locations.

74 . The method of claim 72 or 73 , comprising maintaining the inflation pressure at a substantially constant level.

75 . The method of claim 72 or 73 , comprising varying the inflation pressure to vary the pressure applied to the surrounding bore wall to optimise reservoir production.

76 . A downhole apparatus comprising a base pipe and at least one fluid pressure deformable chamber mounted thereon, the chamber having a plastically deformable wall.

77 . The apparatus of claim 76 , wherein the fluid pressure deformable chambers are non-concentrically mounted on the base pipe.

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

providing downhole apparatus comprising a base pipe and at least one fluid pressure deformable chamber mounted externally thereon, the chamber having a plastically deformable wall; and

inflating the chamber to plastically deform the chamber wall.

79 . The method of claim 78 , comprising mounting the fluid pressure deformable chambers non-concentrically on the base pipe.