Under Pressure

Paul Boughton
Oil and Gas operators are dealing increasingly with higher temperatures and higher pressures, deeper water, high H2S and CO2 content, erosive conditions and extremes of temperature. Technological innovation, ingenuity and incremental qualification of design are key to ensuring that these fields can be developed safely and with zero impact on the environment.
BEL Valves Ltd has a particular focus on high pressures, critical valve applications such as emergency shut down valves and high integrity pressure protection systems.
Pressure ratings have not suddenly increased. There have been continual, incremental requirement rises over a number of years, each new challenge building on previous knowledge and technologies. BEL Valves is now regularly providing subsea valves rated greater than 10,000 psi.
Pressure requirements are now moving into the ‘Extreme’ and ‘Ultra’ high pressure ranges. So although BEL Valves already develop solutions for 15,000 psi subsea valves in bore sizes ranging from 2 – 14”, higher pressures are also being explored.
Ratings to 20 000psi and above are now the new target to aim for, at nominal bore sizes tending to be at 7-in and below. All valve products at these ratings need to be qualified as a minimum base point to API 6A PR2, and API 17D as no fully qualified technology exists in the market today.
Specific consideration is given to full life cycle testing which raises development requirements for:

* Materials; the choice and availability of materials is highly dependent on the nominal bore size of the valve, the full temperature range, both positive and negative and the process conditions. All of these factors affect the material stability and therefore the ability to predict deflection and permanent set.
* Coating technologies: Closely linked with the issues of thermal expansion of different materials, the coating technology choices are also critical.
* Temperatures: are crucial to valve material selection, but also significantly affect seal technology selection. Temperatures below -460 C and above 1500 C create significant challenges but are more onerous and unique in combination.
BEL Valves will be at Offshore Europe in Aberdeen, UK, 6th to 8th September.

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BEL Valves Ltd is based in Newscatle-upon-Tyne, UK. www.belvalves.co.uk

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