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 is disclosed of creating an annular seal around a tubular element for use in a wellbore. The method comprises providing at least one seal layer of a flexible sealing material susceptible to swelling upon contact with a selected fluid, the seal layer having a first edge and a second edge, and helically winding each seal layer around the tubular element so that the first and second edges extend opposite each other along the tubular element and so that the first and second edges seal relative to each other upon swelling of the flexible sealing material. The tubular element is lowered into the wellbore, and the selected fluid is allowed to contact each seal layer so as to induce swelling of the flexible sealing material whereby the first and second edges seal relative to each other.

Abstract: A method is disclosed of creating an annular seal around a tubular element for use in a wellbore. The method comprises providing at least one seal layer of a flexible sealing material susceptible to swelling upon contact with a selected fluid, the seal layer having a first edge and a second edge, and helically winding each seal layer around the tubular element so that the first and second edges extend opposite each other along the tubular element and so that the first and second edges seal relative to each other upon swelling of the flexible sealing material. The tubular element is lowered into the wellbore, and the selected fluid is allowed to contact each seal layer so as to induce swelling of the flexible sealing material whereby the first and second edges seal relative to each other.

Abstract: A wellbore system comprises a borehole formed in an earth formation, the borehole having a borehole section containing a volume of gravel pack particles and at least one body of a swellable material. Each body of swellable material is adapted to expand from an unexpanded state to an expanded state upon contact of the swellable material with a selected fluid, wherein a flow passage is present in said borehole section allowing fluid to bypass the volume of gravel pack particles when the body of swellable material is in the unexpanded state. The body of swellable material is arranged to substantially close the flow passage upon expansion of the body of swellable material to the expanded state.