Simulation Research On Measurement Of Water Cut In Horizontal Oil-water Two-phase Flow By Combined Capacitance Sensor

Horizontal wells play an important role in the development of modern oilfields because of their advantages of improving oil recovery and reducing the cost of oilfield development.Water cut is an important measurement parameter of horizontal fluid production profile logging technology.However,the measurement of water cut is generally influenced by the flow pattern,and the existing capacitance sensors can not simultaneously have good resolution in low flow rate and oil-water stratification.Therefore,in order to meet the actual logging requirements of horizontal oil-water two-phase flow,this paper presents and designs a new type of combined capacitance sensor,and carries out simulation experiment and structure optimization.This paper focuses on the following aspects.Firstly,in order to solve the problem that the flow pattern of oil-water two-phase flow has an impact on the sensor measurement under horizontal conditions,the simulation experiments of flow pattern of horizontal oil-water two-phase flow under non-collecting and collecting conditions are carried out.GAMBIT is used to construct non-collecting and collecting horizontal pipelines and grid them.FLUENT software is used to simulate the model under different working conditions.And the flow pattern of oil-water two-phase flow is analyzed.It provides some theoretical support for the analysis of the response characteristics about the combined capacitance sensor under different flow patterns.Secondly,a combined capacitance sensor is proposed to solve the problem of low water cut measurement resolution for horizontal oil-water two-phase flow under different flow patterns.COMSOL is used to build models and simulate the electrostatic field of the combined capacitance sensor.Through sensitivity analysis of different electrode length,channel radius and thickness of insulating layer in metal layer electrode,the optimal structure of composite capacitance sensor is obtained.The response characteristics of the optimized sensor under six different flow patterns are simulated and analyzed,and the different modes of oil bubble contact electrodes are simulated,which lay a theoretical foundation for the actual measurement.Finally,through static and dynamic experiments,the response characteristics of the combined capacitance sensor under different flow rate and water cut are analyzed.The correctness of the simulation experiment is verified,and the response rules of the combined capacitance sensor in horizontal oil-water two-phase flow with different flow rate and water cut are obtained.The resolution of combined capacitance sensor is better than cylindrical capacitance sensor obviously.