Patent ID: 6651743
Filing Date: 2003-11-25
Classification: E21B

Abstract:
A stage cementer assembly for a cementing operation to cement at least a portion of a tubular casing string within a subterranean wellbore, the stage cementer including a cementer axis aligned along a central through bore, comprising:a cementer housing for fixed interconnection with and positionable along the casing string, the cementer housing including one or more cementing ports for passing fluid from the central through bore to outside the cementer housing, the cementer housing including an upper end above a lower end; an opening sleeve assembly positioned within the cementer housing, the opening sleeve assembly including a non-drillable opening sleeve portion and a drillable opening sleeve portion, the opening sleeve assembly having a seal differential with respect to the cementer housing for moving the opening sleeve assembly in response to a fluid pressure in the cementer housing from a closed position for preventing passing fluid through the one or more cementing ports to an opened position for passing fluid through the one or more cementing ports; a closing sleeve assembly positioned within the cementer housing, the closing sleeve assembly including a non-drillable closing sleeve portion and a drillable closing sleeve portion, the closing sleeve assembly including a closing plug seating surface for sealingly engaging a closing plug thereon to move the closing sleeve assembly in response to another fluid pressure in the stage cementer housing from an opened position for passing fluid through he cementing port to a closed position for preventing fluid from passing through the cementing ports; and the cementer housing including an opening sleeve seat along the central through bore for preventing rotation the drillable sleeve portion during drill-out.