BEL Valves & Actuators for High Temperature/High Pressure (HP/HT) Applications

There are regions across the globe containing hydrocarbons at great depth, high pressure and temperature. The North Sea, Gulf of Mexico, Indonesia, China & Caspian Sea all have hydrocarbon deposits to exploit, but at a cost. As reserves of existing oil and gas deposits begin to deplete, however, the drive to develop these reserves has been growing.

Due to BEL Valves’ extensive experience of high pressure valves we pioneered some of the earliest developments of high pressure, high temperature hydrocarbon reservoirs in the North Sea, back in 1996. Since then BEL Valves has supplied valves and actuators for many of these projects for both surface and subsea applications around the world.

High pressure and high temperature individually present problems when designing equipment for oilfield service. Weight and space is often a significant factor, but when designing for high pressure, valves are necessarily larger and heavier.

Material choice therefore is key when dealing with high pressures. Steels need to have high strength that can be heat treated to maintain the strength throughout the thickness of the metal and must also have excellent corrosion resistance. The best solution to this is to make the body and bonnet from a high strength steel and weld clad all of the internal surfaces with the corrosion resistant material.

Designing equipment for high temperature creates equally challenging but different problems, the most significant of these is sealing. Gate and Ball valves typically have some form of non metallic seal on the seat ring and stem. These seals are made from thermoplastic compounds that can operate at temperatures in excess of 250OC but as the pressure increases the working temperature decreases creating the first hurdle. Secondly the seal materials used for high temperatures are generally rigid at room temperature making it difficult to achieve a gas tight seal at low temperature.

BEL Valves therefore ran an intensive 12 month program of seal testing to overcome this which resulted in a sealing configuration that was suitable for both high and low temperature.
As the exploration of hydrocarbon bearing regions across the world enters more challenging environments, more high pressure, high temperature applications are being discovered. The specifications are getting more demanding, current pressure is in excess of 1380 bar (20000psi) and temperature in excess of 200OC. Only by the use of systems such as HIPPS, High Integrity Pressure Protection System, will these fields be developed. The HIPPS will enable lower pressure equipment to be used downstream of the HIPPS. However even HIPPS valves will have to work in more extreme high pressure, high temperature conditions.

Bel Valves, Tel: 0191 265 9091
Website: www.belvalves.co.uk

Published: 31st March 2010