Research On Water-cut Meter For Crude Oil Based On Capacitance-conductance Technique

Measuring the water cut of the crude oil is an important work in the oilfield. During the process of oil producing,transportation,oil-water separation, it is indispensable to measure the water cut of the two-phase oil-water flow. For this reason, it is significant to design and develop the non-radioactive,low-cost water cut meter which is suitable to the full scale online measuring for domestic applications.This paper presented a new measurement method based on capacitance-conductance technique on basis of studying and comparing many measurement techniques. Designed the parallel-plate shape sensor, meanwhile the new capacitance-to-digital converter was applied to measure the tiny capacitance with high precision and the new impedance-to-digital converter was applied to measure the conductance. Furthermore, designed the new water cut meter for crude oil based on the DSP chip TMS320LF2407A. Experiments have been done in the laboratory using the mixture of tap water and diesel oil, and the sensors' response characteristic versus water cut was obtained. The two methods multiple regression analysis and BP network were used in the data processing of water cut meter. Results show that the effect of BP network technique is better than that of multiple regression analysis obviously. It can achieve the expected goals not only in the precision but also in the generalization.Practice of the paper came to the conclusion that the capacitance technique and conductance technique are potential in water cut measurement while combining the two techniques to realize the water cut measurement for full scale is feasible. In addition, the BP network is competent in solving the nonlinear problem, and it's effective and suitable for information fusing in water cut measurement.