METHOD AND APPARATUS FOR THE MEASUREMENT OF THE MASS FLOWRATES OF FLUID COMPONENTS IN A MULTIPHASE SLUG FLOW

摘要

2136175 9324811 PCTABS00028 A dual energy gamma-ray transmission gauge (10) includes radioisotope sources (11) for emitting gamma-rays (13) of two different energies. Gauge (10) also includes a gamma-ray detector which produces signals as a response to the detected gamma-rays. A single energy gamma-ray transmission (17) is disposed upstream of gauge (10) for providing further signals indicative of the respectively detected gamma-rays. These signals are subsequently directed to a processing computer (16) together with signals indicative of the pressure and temperature of the flow obtained from two sensor means (18, 19). The intensities of the gamma-rays are recorded and thereafter a value indicative of the mass flow rates of oil, water and gas can be calculated. The mass flow rates of liquid phases are calculated at substantially all times, however, the phase fractions of oil and water are determined only when a slug is passing gauge (10) in order to maximise the path length of the liquid phase through which the gamma-rays pass.