Research On Optimal Oil-water Interface Height And Control Process Of Horizontal Three-phase Separator

As China's oilfield production enters the final stage,the water content of oilfield production fluids continues to rise.The horizontal three-phase separator has become an important mechanical device for the processing of oilfield production fluids in the joint station because of its strong applicability and mature design theory.The internal settlement mechanism of the horizontal three-phase separator is based on the Stockes theory,and the optimization research and control process of the oil-water interface inside the separator is still in the stage of constant exploration and improvement.Based on the theoretical study of separator oil-water separation,this paper optimizes the oil-water interface control height in the horizontal three-phase separator control process.Under the qualified conditions of the oil-water separation index of the separator,the ratio of the sewage discharge flow rate based on the separator to the overall flow rate of the liquid phase is the dehydration efficiency of the separator,and the relationship is established,which is between the dehydration efficiency of the separator and the height of the oil-water interface.Then,the mathematical model of the oil-water interface height with the sewage outlet flow rate,the oil phase outlet flow rate and the dewatering efficiency of the separator is established respectively,and which is solved by genetic algorithm.Finally,by substituting the basic structural parameters of the separator and the physical properties of the crude oil,combined with the constraints and control variables,the optimum liquid level for the operation of the horizontal three-phase separator is calculated to be 0.688 times the diameter of the separator.The dewatering efficiency is optimized.Accroding to the research on the operation process of the separator of the joint station,a dynamic mathematical model is established for the height control process of the oil-water interface inside the separator,and which is simplified by the linearization method.Combined with the actual running production data of the site,the expression is obtained by calculation,and which is simulated by MATLAB fourth-order Runge-Kutta and draw the simulation step curve.The output change trend of the dynamic mathematical model is consistent with the output response of the actual separator operation,and the reasonable accuracy of the dynamic mathematical model is verified.In addition,the paper analyzes the importance of the oil-water interface control technology of the horizontal three-phase separator and the current status of the control technology,and analyzes some shortcomings of the mechanical manual oil-water interface technology.By introducing a more advanced and precise control of the RF admittance oil-water interface controller,PID controller and electric control valve.The oil-water interface control process of the horizontal three-phase separator on the site was upgraded,and a single-loop feedback control system was established to achieve stable control of the oil-water interface of the separator.