Thermally-Actuated Gas Lift Safety Valve: Apparatus and Operational Procedure

Problem: Danger of oil passing from the tubing into the annulus (backflowing) when the reverse-flow check valve opens or has leaks. Technology: This invention proposes the design of a thermally-actuated gas lift safety valve that prevents oil backflow. In a correctly-operating gas-lifted oil well, gas is pumped down the well annulus, passes through a gas lift valve into the well tubing, and helps lift the oil. In a backflow event, oil passes instead through the gas lift valve into the annulus. Because oil is warmer than injection gas, backflow heats the gas lift valve. The new design uses shape memory alloys to close the valve in this event. Christopher Noble crn@mit.edu