Diagnostics of salty water-in-oil two-phase flow

This paper concerns the features of a measuring device as well as two semitheoretical algorithms to find values of water cut, w, and flow rate, Q, for inverse emulsion flow “salty water-in-oil”. The measuring device is based on a combination of an RF-sensor, responding to complex dielectric permittivity of the flow, and a narrowing device. It is an upgraded variant of a diagnostics system to find characteristics of two-phase cryogenic flows that have been described by us earlier. The semitheoretical algorithm to find w- and Q-values is a paramount constituent element of the considered system. It takes into account hydrodynamic and electrodynamic features of the water–oil flow, the main of them are high viscosity value and conductivity of the salty water. Tests of the discussed measuring system with flows contained real crude oil and different kinds of water, including formation/stratum water, are described. A comparison of the experimental results and calculations based on the developed semitheoretical algorithms, are demonstrated and discussed. This comparison has allowed errors of the described algorithms to be estimated.

► A system for measuring flow rate and water cut of oil–water–salt flows is presented.
► It is based on a combination of an RF-sensor and a narrowing device.
► The system have been designed and tested in the range of water cut less than 0.7.
► The main attention is paid to developing an algorithm to process the measured data.
► The error of determining the water cut is 0.5%, and the error of flow rate is 5–6%.