Method and apparatus for supporting a tubular

摘要

A spider and method for supporting a tubular within a well bore. Radial dogs, controlled by cylinders that extend and retract simultaneously, are operable to support the tubular by the lower lip of a box connector. When a tubular connector is set down upon the dogs so as to depress one or more triggers located thereon, an interlock in a control system is actuated to prevent movement of the dogs. However, even while the spider is thus loaded, the dogs may nevertheless be retracted via an emergency override mechanism thereby allowing the tubular to be dropped into the wellbore. When the tubular has been lifted off of the triggers, the interlock is deactivated, and the dogs of the spider can be operated once again. The triggers may actuate sensor valves located within the dogs, which in turn actuates an interlock valve isolating the flow path of the cylinders.

主权项

1. A spider for vertically supporting a tubular, comprising:
a frame defining a vertical axis therethrough; at least one actuator carried by said frame; a plurality of dogs radially disposed about said vertical axis, said plurality of dogs coupled to said at least one actuator so as to be movable by said at least one actuator between an inward extended position and an outward retracted position, said plurality of dogs arranged so that when in said extended position, a tubular coaxial with said vertical axis may be vertically supported by said plurality of dogs; a first trigger located on a first of said plurality of dogs so that said tubular influences said first trigger from a first state when said tubular is not vertically supported by said plurality of dogs to a second state when said tubular is vertically supported by said plurality of dogs; and a control system operatively coupled between said first trigger and said at least one actuator, said control system including a first selector operative to selectively move said plurality of dogs by said at least one actuator between said extended position and said retracted position when said first trigger is in said first state and to prevent movement of said plurality of dogs by said at least one actuator when said first trigger is in said second state.