DUET MULTIPHASE FLOW METER

Abstract

CSIRO Minerals has developed a Multiphase Flow Meter (MFM) for measuring oil, water and gas flow rates in offshore topside and sub-sea oil production pipelines. In 1997 Kvaerner Oilfield Products (KOP) signed an exclusive licence agreement with CSIRO Minerals for production and further development of the dual energy gamma-ray transmission (DUET) MFM. This new technology has the potential to save the oil industry many millions of dollars in capital, operating and maintenance costs. Essentially, the MFM consists of two specialised gamma-ray transmission gauges, pressure and temperature sensors, which are mounted on a pipe spool carrying the full flow of the well stream, and processing electronics. Measurements of the intensities of transmitted gamma rays are made to infer the proportions of oil, water and gas, and flow velocities are determined from cross-correlation of gamma-ray signals.

Prototype MFM's have completed several Australian and overseas trials, including an extended four-year trial (1994–1998) on Esso's West Kingfish platform in Bass Strait and Texaco's test loop facility in Humble, Texas. During these and other trials the MFM has determined water cut to accuracies of 2–4%, and liquid and gas flow to accuracies of 5–10%, up to a gas volume fraction (G VF) of 95%. Full production versions of the MFM are presently under construction by KOP, and the first installation is due to take place early in 2000 at Texaco's Captain oilfield in the North Sea. CSIRO Minerals is presently consulting with the Australian oil industry to assess interest in the development of a wet gas MFM, capable of operating at GVF's in excess of 95%