A well controlled by two hydraulically operated subsurface safety valves made up in the tubing string. A first valve is mechanically locked in open position and the second valve is utilized to control flow through the string. Upon malfunction of the second valve it is locked in open position and the first valve is released from its locked open position and is utilized to control flow through the string.
申请公布号
US4469179(A)
申请公布日期
1984.09.04
申请号
US19810331641
申请日期
1981.12.17
申请人
OTIS ENGINEERING CORPORATION
发明人
CROW, ROBERT W.;VINZANT, MICHAEL B.;SCHWENDEMANN, KENNETH L.