Abstract: An expandable downhole seal includes a sealing portion and a deflecting portion adapted to move axially relative to each other to effect radial displacement of the sealing portion, wherein at least one of the sealing portion and the deflecting portion includes a swelling material. In use, radial expansion of the downhole seal may be achieved by the radial displacement of the sealing portion in combination with swelling of the swellable material. A support member is provided to support the sealing portion and deflecting portion.

Abstract: An expandable downhole seal includes a sealing portion and a deflecting portion adapted to move axially relative to each other to effect radial displacement of the sealing portion, wherein at least one of the sealing portion and the deflecting portion includes a swelling material. In use, radial expansion of the downhole seal may be achieved by the radial displacement of the sealing portion in combination with swelling of the swellable material. A support member is provided to support the sealing portion and deflecting portion.

Abstract: A seal arrangement includes a plurality of seal elements arranged in series. At least one seal element has a predetermined rated pressure and includes a relief arrangement permitting relief of pressure across the seal element at a predetermined level lower than said rated pressure.

Abstract: A method of creating a borehole in an earth formation is provided. The method involves the steps of drilling a section of the borehole and lowering an expandable tubular element into the borehole whereby a lower portion of the tubular element extends into the drilled borehole section, radially expanding the lower portion of the tubular element so as to form a casing in the drilled borehole section, and separating an upper portion of the tubular element from the lower portion so as to allow the separated upper portion to be moved relative to the lower portion.

Abstract: A method of expanding a tubular element is provided, the tubular element having a first portion to be expanded to a first inner diameter and a second portion to be expanded to a second inner diameter larger than the first inner diameter. The method comprising: a) arranging an expandable sleeve of selected wall thickness in said second tubular element portion; b) positioning an expander in the tubular element; c) operating the expander so as to expand said first tubular element portion to the first inner diameter, and operating the expander so as to expand the sleeve to an inner diameter substantially equal to the second inner diameter minus double the wall thickness of the sleeve; and d) retrieving the sleeve from the tubular element.

Abstract: A steerable soil penetration system having a steerable penetration head, which compacts and does not cut away the surrounding soil and which is connected to an elongate flexible tubing such that the orientation of the penetration head can be varied relative to the tubing. The elongate tubing and/or a downhole hammer or tractor pushes the penetration head through the subsurface formation. Preferably the tubing is surrounded by a narrow annulus so that buckling of the tubing is inhibited and the tubing protects the pierced hole against caving in.