Patent ID: 7600571
Filing Date: 2009-10-13
Classification: E21B,Y10T

Abstract:
1. An abandoned well comprising: a surface casing extending upward from a subterranean location; a production casing extending upward from a subterranean location inside the surface casing and having a top end below the top end of the surface casing; a production plate attached to a top end of the production casing and sealing the top end of production casing; a drill guide tube having a bottom end attached to the production plate and extending up from the production plate to a top end of the drill guide tube located above the top end of the surface casing; a surface plate defining a guide hole and attached to a top end of the surface casing such that the drill guide tube extends through the guide hole, and wherein the surface plate is sealed to the top end of surface casing and sealed to the drill guide tube; a vent hole extending from a central passage of the drill guide tube through a wall of the drill guide tube below the surface plate and above the production plate; an internal plug operative to block the central passage of the drill guide tube at a location above the vent hole and below the top end of the drill guide tube; wherein the top end of the drill guide tube is adapted for releasable attachment of a cap and releasable attachment of a pressure control apparatus and drilling tool such that the drilling tool can bore through the internal plug while containing pressurized fluid in the surface casing.