A Modular Differential Dielectric Sensor (DDS) for Use in Multiphase Separation, Process Measurement and Control—Part I: Analytical Modeling

Oil industry increasingly demands accurate and stable continuous measurement of the percent water in crude oil production streams (watercut) over the entire 0 to 100% range. High accuracy and stability are also required for surface measurement to support niche applications such as control of processes which remove trace amounts of oil and particulates from produced water prior to disposal. Differential Dielectric Sensors (DDS) have been developed by Chevron as independent tools connected with multiphase meters for process management and composition measurement. This paper is a two-part paper — the first part (current paper) deals with analytical modeling of the DDS (configured in a single ended mode) and the second part discusses the results of key experimental investigations obtained in a differential mode. The main objective of this paper is to develop appropriate mathematical models for the DDS which characterize the microwave attenuation and phase shift as a function of fluid properties, sensor geometry and operational conditions. Forward models based on the analysis of microwave propagation have been developed for sensors configured as circular waveguides. Results of this project will be useful for optimization and refinement of multiphase meters.