A radio frequency sensor array for dielectric constant estimation of multiphase oil flow in pipelines

The measurement of the single phase portion in a multiphase flow is very important to oil and petrochemical industries. This paper presents a radio frequency (RF) sensor for dielectric constant estimation of two or three phase combinations of oil, water, and gas. The 28-port RF sensor was designed and optimized to operate at 250 MHz. Using the transmission coefficient of each RF sensor port, an equation was obtained for dielectric constant estimation by applying the least squares method. Three different static two phase combinations including oil-water, gas-water, gas-oil and three phase combination of oil-water-gas are experimentally validated with an average measured error percentages of 5.5%, 17.3%, 16% and 6.2%, respectively. A shake test for the three phase combination was performed to resemble an actual three phase flow and the average measured error was 9.3%. The proposed sensor can estimate two or three phase combinations of oil, water, and gas with an average error less than 10%. The proposed sensor is low cost, with low complexity and is the first to provide low error estimations to 2 or 3-phase static or dynamic flows.