a Daqing Production Well Logging Institute, Daqing City, Hei Longjiang Province 163453, People's Republic of China
b Harbin Institute of Technology, Harbin, People's Republic of China
Abstract:
A new theoretical model for a capacitance sensor used for measuring water holdup in production logging is proposed in this paper. The model realizes that the capacitance sensor is sensitive to oil droplets that collide against the sensor's inner electrode coated with an insulator when the water is electrically conductive and is the continuous phase in an oil/water bubbly flow. The sensor still has the ability to distinguish between oil and water in this case, its sensitivity decreasing with fluid velocity. The experiments were performed in a multiphase flow loop, and the results strongly confirm the theory. On the basis of the model, the measuring principle of the sampling-type capacitance tool is discussed, and an attempt to evaluate average oil droplet size with the capacitance sensor in the case of oil in water is also made.