Safety valve apparatus and method

摘要

A safety valve for controlling flow in a flow line is disclosed which is especially adapted for use in emergency control of a producing well. The apparatus includes means for securing a punch out tube in series with the flow line and ramming means for ramming the punch out tube and displacing at least a portion of it from the flow path of the flow line and sealing the flow line. The punch out tube comprises top, bottom and middle cylindrical members stacked end to end with an elastomeric seal provided in channels resulting from cooperating grooves formed in the end surfaces of the members. When the middle member is rammed, while the bottom and top members are fixed within the valve body, the middle member is displaced to a valve recess and the ram covers and seals the outlet flow path of the valve. The valve is adapted to be attached between production casing of a production wellhead and a production tree. The production tubing is supported within the valve body. Production flow path is achieved by coupling of the punch out tube to the production tubing and the flow path of an annular packoff. The production tree or a tubular extension to the tree is attached to the top of the valve body. A method and means for accomplishing the method are provided for replacing the punch out tube without removing the production tree from the valve body. A method for installing the valve between a production wellhead and a production tree is also provided.