Non-intrusive microwave system for multiphase flow metering

Accurate and reliable measurement of oil, gas and water flow rates as they flow along a pipe as a mixture continues to be a challenging problem in the oil and gas industry. Most of the solutions rely on radioactive sources. This paper explores the use of microwave sensors for flow rate measurement. Microstrip Patch sensors in transmission mode and a near field coaxial probe in reflection mode are used to estimate water fraction even in lossy (saline) medium using physics based models with minimal calibration. Reflection measurements from the Patch sensors are used to estimate gas fraction using empirical models which can enable measurement of gas in high loss cases. Gas velocity is measured from cross correlation. A low cost 5-port measuring instrument was built to do reliable reflection and transmission measurements over a wide temperature range. The microwave system was tested in in-house and external flow loops and in the field under varying temperatures and flow conditions and test results are presented in this paper.