Wellhead Shut Off and Control

Background: Wellheads

With the demand for renewable energy continuing to increase, Geothermal power has become a focal point in generation company portfolios. Geothermal energy is extracted without burning any fossil fuels, ensuring a reduction in greenhouse gas emissions. Geo-fields are currently producing about one-sixth of the carbon dioxide of a clean natural gas-fueled plant. Moreover, geothermal energy is always available unlike solar and wind power.

Whether it is a dry steam, flash, or binary cycle plant design, everything begins at the wellhead. Often separated from the plant by significant distances, production wells include emergency shutoff valves (ESV) and flow control valves which play a key role in the process. Therefore, they must function dependably to ensure no interruption of the flow of steam or brine to the plant.

Reliable shutoff and flow control valve operation at production wells can cause a major headache thanks to scaling and potential harsh environmental conditions. As geothermal fluids travel through the earth’s crust towards the wellhead, they absorb many dissolved minerals and gases. Reservoir temperature and saturation levels dictate the amount of scaling at the well caused by these minerals. Consequently, build-up on valve internals begins immediately and can reach catastrophic levels soon after.