| Most of the land oil fields in China have entered the middle and late stage of oil exploitation.Owing to the characteristics of long-term water injection and low permeability and low production,the oil well presents the characteristics of three phase flow and high water cut.It is important to study the phase holdup measurement method of oil gas water three-phase flow to improve oil production characteristics and optimize reservoir management.Gas phase is an important factor affecting the flow pattern of three-phase flow.There is no three-phase flow measurement method in traditional multiphase flow measurement technology.And the oil and gas phase flow measurement error is large.Through experiments,it is found that the flow pattern adjustment has a very positive effect on improving the measurement results.In this paper,the method of gas and liquid pre separation for gas and liquid three-phase flow in gas and liquid pre separator is studied.In the measurement of phase holdup of oil,gas and water phase,the flow pattern of fluid is adjusted to improve the flow range and measurement accuracy of the three phase flow phase holdup.In this paper,the pre separation of gas and liquid is carried out by gas liquid pre separator to the three-phase flow of oil and gas water.Most of the gas is separated,and the interference of gas to the multiphase flow measurement device is reduced.In the measurement of the phase holdup of oil gas water three-phase flow in downstream,the flow pattern of the fluid is adjusted to improve the upper limit and the measurement accuracy of the three-phase flow phase holdup measurement.Based on the range of oil and gas flow in oil field,the method of gas phase separation is studied to ensure the measurement accuracy of oil and water flow.Numerical simulation method is used to verify the parameters,and several different flow simulation experiments are carried out.The results show that the gas separation efficiency of the gas liquid separator is above 96%.The design parameters were optimized,and the size of the gas-liquid separator was determined.On the basis of the numerical simulation research,a gas liquid pre separator is designed based on the field experiment environment.On the multi phase flow experiment device of Daqing oilfield,an experimental study is carried out by combining the gas liquid separator with the flow pattern regulating oil and gas water three-phase flow measurement device.Under the conditions of diesel,tap water and air in the experimental medium,the experiments of gas water two-phase flow and oil and gas water three-phase flow have been carried out successively.It is proved that the gas liquid separator can achieve effective gas liquid separation in the range of gas flow rate of 40 m3/d and the total gas and liquid flow rate of 90 m3/d,which provides a good method for the three-phase flow measurement device of the downstream flow pattern control.The test environment has improved the measurement effect of oil-water separated flow rate.The measured oil and water flow rate has a good linear relationship with the standard flow rate provided by the multi-phase flow device.This research provides a new method for the measurement of low velocity oil and gas water three-phase flow.The method is applicable to the measurement of oil and gas water in high water cut oil fields in China.It can provide accurate production data of oil wells,help to improve the production characteristics of oil wells,ensure the safety and efficiency of oil production equipment,optimize the management of oil reservoirs,and realize the economy of oil fields.Effective development. |
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