Case 14632

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

Keywords:

Gas Lift Valve (GLV), Thermally-Actuated, Shape Memory Alloy Wires

Applications:

Oil Production

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.

Advantages:
  • Prevents oil from entering the annulus
  • Tunable transition temperatures of the shape memory alloys to match well conditions
  • Invention and operational procedures work well with a safe level of hysteresis

Inventors:
  • Assistant Professor Franz S. Hover (Department of Mechanical Engineering, MIT)
  • Eric W. Gilbertson (Department of Mechanical Engineering, MIT)
  • Jose Arellano (Chevron Corporation)
  • Eduarto Colina (Chevron Corporation)
  • Bryan Freeman (Chevron Corporation)

Intellectual Property:

US Patent Application 13/075424 on March 30, 2011

Publications:

Gilbertson, E., F. Hover, J. Arellano, and B. Freeman, "Design of a Thermally-Actuated Gas Lift Safety Valve," ASME International Conference on Offshore Mechanics and Artic Engineering (OMAE), Rotterdam, June 2011.

Last revised: November 15, 2011

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