Safety slip ram
AssigneeBaker Hughes Incorporated
InventorGarry R. Kaiser
Life of this patent
Estimating the term…
Abstract
A pair of ram blocks are provided such that when they are actuated hydraulically to move together, they present an opening which has a series of gripping members downwardly biased. Removal of tubulars or tools from the well bore works against the bias to retract the grippers so that removal can be accomplished. However, if there is an accidental release, the bias pushes the grippers toward the tubular or tool to grip it to prevent loss into the well bore. The ram blocks can be retracted for run-in to the well bore.
Claims11
A method for preventing accidental dropping of a tubular into a wellbore comprising:
- removing the tubular through a blowout preventor;
- configuring said blowout preventor to allow removal of the tubular while preventing dropping of the tubular into the wellbore;
- providing a selective gripping mechanism on at least one of the ram blocks of said blowout preventor;
- maintaining sliding contact between said selective gripping mechanism and the tubular as the tubular is removed from the wellbore.
A blowout preventer-mounted gripping device, comprising:
- at least one ram block, said ram block supporting a gripper which allows selective removal of the tubular and grips the tubular if it moves in an opposite direction;
- said ram block cams said gripper, along a sloping surface thereon, if the tubular exerts a force on said gripper in a downhole direction;
- a biasing member to cam said gripper along said sloping surface toward an extended position where it can maintain contact with the tubular while the tubular is removed from the wellbore;
- whereupon if the tubular begins to drop, the contact between said gripper and the tubular is enhanced by the force of said biasing member to force said gripper along said sloping surface, to stop the tubular.
Dependencies are inferred from the claim text.