Kerr-McGee North Sea (UK) Limited - Gryphon Alpha FPSO Monetary Application for Multiphase Meters

摘要

In 2001 Kerr-McGee (KMG) and its partners made the decision to develop the marginal Maclure and Tullich oil fields, by tying them back to the Gryphon Alpha FPSO. Both of the new fields have a markedly different ownership to the Gryphon field. Whilst there was a compelling requirement for accurate measurement of production between the three fields, it was similarly important to minimise Capex to ensure the developments were economically viable. Given this, multiphase metering was considered to allocate between the different ownerships, as opposed to traditional separator metering. The Maclure and Tullich fields first produced oil in July and August 2002 respectively. This paper discusses the multiphase meter selection criteria, installation, independent testing and the first three months of operation. The meters selected were the Framo/Schlumberger Phase Watcher (Vx) in two different sizes (52mm and 88mm). Independent flow tests, conducted at the U.K. National Engineering Laboratory and at ChevronTexaco's Humble facilities demonstrated that an accuracy on the oil phase of 5% of reading could be achieved for typical gas volume fractions of 60 to 80% and water cuts less than 20%. Offshore the multiphase meters are verified against the test separator coriolis meters, these verifications reveal that the accuracy on the oil measurement is within the target range of 5% of reading.