Shut-off control system for oil/gas wells

摘要

A shut-off control system for an oil/gas well casing is described which is intended to protect a discharge manifold from which the oil or gas is extracted. An explosion-proof bunker is positioned below the ground level and contains a valve which can be opened to permit flow of oil or gas through the well casing or to a closed condition in which the flow is inhibited. An actuator is mechanically coupled to the valve. A normally inaccessible closure system is provided which is at least partially disposed below ground level and is connected to the actuator for selectively controlling the condition of the actuator to permit or inhibit the flow of oil or gas through the well. In one embodiment, a fail-safe system is described which includes hydraulic accumulators in the bunker and a control circuit for monitoring and sensing alarm or abnormal conditions for automatically applying energy stored in the accumulators to the actuator to automatically close the flow of oil/gas in the well. In another embodiment, an enclosure is arranged below ground level at a location the spatial coordinates of which are known. Hydraulic conduits and connectors within the enclosure are connected to the actuator, so that upon location of the enclosure selective application of a pump to the connectors can be used to close the valve. Both embodiments can be used separately or together to provide extra redundancy and reliability.