Patent ID: 6450262
Filing Date: 2002-09-17
Classification: E21B

Abstract:
An isolation tool for use in diverting the upward flow of drilling fluid within the annulus between a marine riser and a drill string extending therethrough for return to the surface outside the riser, comprisinga housing adapted to be connected as part of the riser and having a bore through which the drill string may extend during the drilling of a well, an annular recess about the bore, and a side port below the recess for connecting the bore to a conduit leading to the surface; an actuator within the recess which normally occupies a position forming a continuation of the bore; and an insert packer including a sleeve of elastomeric material adapted to be lowered into and raised from a landed position in the bore opposite the actuator so as to receive a drill string therethrough; said actuator being responsive to the supply of control fluid thereto from an outside source to contract the sleeve about the drill string, so that drilling fluid flowing upwardly in the annulus between the riser and string is directed into the side port, and responsive to exhaust of the control fluid to return to its original position in which the actuator sleeve may expand to permit retrieval of the insert packer.