Patent ID: 6431273
Filing Date: 2002-08-13
Classification: E21B,Y02E

Abstract:
A hydraulic anchor packer for use in a well bore comprising:an inflatable packer element incorporating a cylinder and an elastomer sleeve provided on the exterior surface thereof, the elastomer sleeve being retained by retaining means adjacent the cylinder at the end portions of the sleeve but free of the cylinder intermediate the end portions; an aperture defined by the wall of the cylinder for connecting the exterior of the cylinder in a region where the elastomer sleeve is free thereof to the interior of the cylinder; means for causing fluid from within the cylinder to flow through the aperture and between the elastomer sleeve and exterior surface of the cylinder to radially expand the elastomer sleeve; means for trapping fluid located between the elastomer sleeve and the cylinder to prevent relaxation of the elastomer sleeve; said fluid trapping means comprising a piston moveable by an application thereto of fluid pressure; and pressure relief means for permitting fluid located exteriorly of the packer to move past the elastomer sleeve as the sleeve expands whilst in engagement with a well bore wall during use; wherein means integral with said fluid trapping means is provided for rendering the pressure relief means inoperative when said fluid trapping means is activated so as to trap fluid located between the elastomer sleeve and the cylinder.