利用LWD测井资料预测油藏衰竭程度和生产气油比

Prediction of reservoir depletion degree and production GOR using logging-while-drilling data

综合利用LWD、MDT测井以及生产动态资料,对衰竭式开发油藏的衰竭程度(地层压力)、单井初产气油比与LWD测井响应的关系进行了研究。研究不同衰竭程度和生产气油比时LWD体积密度和中子孔隙度测井响应特征发现,当地层压力小于饱和压力时,LWD测井密度和中子孔隙度曲线重叠区的大小与油藏衰竭程度和生产气油比具有一定关系,重叠区越大,地层压力越低,油藏衰竭程度就越严重,生产气油比也越高。经多元统计回归,得到地层压力、生产气油比与密度孔隙度和中子孔隙度之差的函数关系。通过对DLL油田Ⅱ区块实际资料的统计分析,建立了利用密度孔隙度和中子孔隙度之差预测地层压力和生产气油比的经验模型,预测结果与MDT测井压力资料和生产气油比资料相符,证明该方法有较高的精度。

Data of logging-while-drilling （LWD） log, formation pressure from MDT measurement, and production performance are used to study the relationship between depletion degree （formation pressure）, initial production GOR of single well and LWD response of depletion development reservoirs. The results indicate that the overlap between density and neutron porosity curves from LWD data is related with reservoir depletion degree and production GOR when the formation pressure is less than the bubble point pressure. Larger overlap between two curves corresponds with lower formation pressure and higher GOR. The function among the formation pressure, production GOR and porosity difference between density and neutron porosities can be derived from multianalysis and regression. Through the analysis of the actual data from Block II of DLL Oilfield, empirical formulas have been established to predict formation pressure and production GOR from the porosity difference between density and neutron porosities. The prediction results correspond with MDT measurement and production GOR data, which proves the high reliability of the methods.