Research On Detection Method And Instrument Realization Of Constant Temperature And Differential Heat Flowmeter

Downhole flow dynamic detection plays a very important role in oil exploration and development.The measurement of flow can judge the production status of oil Wells,predict the production of oil Wells,and finally achieve the purpose of controlling production flow,improving oil recovery efficiency and protecting the reservoir.At present,the vast majority of downhole flowmeters can not solve the problem of low flow detection,and there is no good solution for the low production well flow detection domestically.Therefore,it is of great engineering significance to develop a flow detection instrument suitable for low liquid production wells.Based on the thermostatic differential thermal mass flow measurement method,this paper has carried out research and development work on the flow detection of downhole micro liquid phase(oil,water):(1)A control algorithm of temperature difference based on piecewise PID is proposed,which can achieve and maintain the temperature difference in the preset temperature difference state within 260s.(2)The influence of ambient temperature and pressure on the measurement results is analyzed.The theoretical and experimental results show that the results will increase with the increase of temperature and pressure.(3)According to the actual downhole application requirements,the array constant temperature differential thermal flow detection scheme is proposed,and the first downhole array constant temperature differential thermal flow logging tool in China is developed.Research and experimental results show:The array thermostatic differential heat flow detection method proposed in this paper can reflect the change of surrounding fluid flow in real time according to the heat taken away by the heat source.It has a resolution of 2 m~3/day in single-phase oil and 1 m~3/day in single-phase water.It is suitable for the measurement of cross section velocity distribution in horizontal and deviated wells with low productivity.Although ambient temperature and pressure can lead to deviations in the test results,the effects of these deviations can be eliminated by correcting the template to achieve accurate downhole flow measurements.The array thermal flow logging tool designed and implemented in this paper aims to solve the problem of flow detection of low fluid production Wells,provide a feasible solution for monitoring the production of mixed fluid in each fluid production interval,and provide oil well fluid production profile data.After engineering industrialization,it can fill in the blank in this field domestically.