Fugitive Emission Specifications ISO 15848-1. The challenge for Spring Energised Seals
01 February 2006
High Perferformance Seals were contacted by one of the largest control valve manufacturers in Europe to design a seal solution capable of handling extremes of temperatures and pressures, and simultaneously meet the leakage values specified in ISO 15848-1 standard.
The valves are to be used in the Kashagan Field Development, Caspian Sea, Kazakhstan. The Kashagan Field is one of the worlds largest hydrocarbon finds; estimates vary between 3rd to 5th largest ever, with over 38 Billion barrels of oil in place.
The Kashagan Field is 50 miles offshore in a very harsh environment; the waters are shallow, 3 to 5mtrs deep; in summer the average temperature is +40°C, the water is frozen solid from November through to March.
There are other serious environmental issues, these vast Hydrocarbon deposits contain a very high percentage of Hydrogen Sulphide Gas - (H2S) - usually called sour gas. A concentration of 2% sour gas in the well stream is high; the Kashagan Field has a concentration of 15% rising to 20%, this is extraordinary.
The contractor for this project has in put in place very stringent fugitive emission rates to reduce the amount of toxic H2S escaping into the atmosphere; they have decided to use the ISO15848 standard for Fugitive Emissions. ISO15848 is still under development but will be approved early in 2006.
The valves operate at -93°C to +121°C, pressures up to 830bar; the required leakage rate for a 2in needle valve = 1.2grams per year! Testing is completed with 97% Helium & measurement is by Helium mass spectrometer; seal life time is 20 years.
Saint-Gobain worked closely with the customer to provide a unique High Performance OmniSeal® sealing solution that handled the combined challenge of severe environmental & service conditions while meeting the stringent leakage rates of the specification.
