一种井眼球状模型自然伽马测井围岩校正方法OA

Due to the influence of highly radioactive shoulder bed,the natural gamma logging response value of thin sand layer in middle mudstone section,Carboniferous,Hudson Oilfield,Tarim Basin is higher,which brings difficulties for shale content calculating and effective reservoir thickness dividing.Different from the existing natural gamma shoulder bed correction method,considering detecting characteristics of natural gamma log,a wellbore spherical model is constructed.Based on the natural gamma ray flux density formula of any point in space at the gamma detector,deduce the contribution factor of finite thickness formation to the measurement of natural gamma detector is deduced,and a natural gamma logging shoulder bed correction method based on borehole spherical model is given.The natural gamma logging shoulder bed correction method based on borehole spherical model is applied to correct shoulder bed effect with the thin sand layer of middle mudstone section,Carboniferous,Hudson Oilfield,Tarim Basin.The natural gamma before and after shoulder bed correction are compared with the core gamma,and the shale content which is calculated by using the natural gamma before and after shoulder bed correction is compared with core wafer data and the modular formation dynamics test results.All these verify the rationality of the new shoulder bed correction method.