Energy dispersive X-ray scatter for measurement of oil/water ratios

A technique for measuring oil and water concentrations in a bulk liquid usi ng energy-dispersive X-ray scatter will be discussed. It is a requirement o f the oil industry to measure accurately on-line the oil/water ratio of flu ids extracted from oil fields across a wide range of gas-liquid flow regime s. To this end, a low cost, robust system is being developed using the ener gy dependence of coherent scatter as a probe to measure oil/water ratios. T he scatter profiles are inherently broad and thus the relaxed energy resolu tion requirements allow the use of CdZnTe detectors suitable for field depl oyment. Energy-dispersive diffraction spectra of a range of oil-water emuls ions have been measured. The ratio of the scattering into two energy window s, where the diffraction spectrum from oil is maximised and minimised with respect to that of water, is shown to be dependent upon the oil/water mixtu re ratios. The measurement is made independent of gas volume flow rate by n ormalisation of the scattered data to the transmission data. A relative err or of 0.6% in the oil/water ratio measurement at 80% water fraction, and in dependent of gas fraction, is obtained. (C) 1999 Elsevier Science B.V. All rights reserved.