A wet-gas flowmeter based on the field-proven downhole fiber-optic multiphase flowmeter has been developed. The flowmeter is based on an extended throat Venturi-nozzle and a Sonar flowmeter. This combination exploits the characteristics of these two devices in wet-gas flows. For the Venturi, there is a well-defined and large over-reading with increasing liquid-loading, whereas this has a significantly lower impact on the total flow rate measured by Sonar. The Sonar-Venturi wet-gas flowmeter has been in development over the past several years and has been tested extensively in industry flow loops. Particular emphasis has been placed on developing a flowmeter with a broad operating envelope that includes a large span of fluid properties, a high turndown ratio, and well characterized response both within and outside its intended operating envelope. The wet-gas performance has been demonstrated at the recently commissioned CEESI 3 phase wet-gas flow loop, yielding total and gas flow rates better than ±5%*, liquid flow rate better than ±0.5 m~3/hr in Type I wet gas,1 and better than ±20% in Type II wet gas. A Red Eye 2G near-infrared (NIR) water cut meter is used to differentiate the oil/condensate and water. The Red Eye 2G has field proven performance in low gas volume fraction (GVF) flows for full range of water cut. A prototype version has demonstrated ±5% water cut uncertainty in high GVF multiphase2 flows and initial testing of the Red Eye in wet-gas flows is showing great promise. The wet-gas flowmeter was also tested at the NEL multiphase flow facility to evaluate whether the measurement capability could be extended beyond the wet-gas envelope. Although the performance in low-pressure multiphase flows did not match the performance seen in high-pressure wet-gas flow, measurement capability was maintained and reasonable performance was demonstrated for the entire range of GVF.
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