| 摘要 |
<p>A downhole safety valve for a subterranean well comprises an axially shiftable valve head which is movable between open and closed positions by an actuating member. The actuating member is axially shifted by a device mechanism which is manipulated by an electric motor. The electric motor is preferably actuated by downhole batteries and the energization and de-energization of the electric motor is preferably controlled from the well surface by electromagnetic waves. A locking mechanism engages the actuating member of the safety valve in its open position through the energization of an electric solenoid, also preferably controlled from the well surface by electromagnetic waves.</p> |
