张量感应测井视值解释方法的改进

三轴张量感应测井可探测地层电导率各向异性,Zhdanov et al.利用在横向各向同性均匀介质中测井响应的低频渐近式给出了由张量感应测井响应提取地层各向异性电导率和井孔倾角与方位角信息的解析公式,为张量感应测井资料解释奠定了基础.但是,他们给出的井孔倾角公式存在双值解的不确定性,其各向异性电导率解也不是最佳近似解.本文以更为简洁的推导和分析方法,给出了单值的井孔倾角解以及近似程度更好的各向异性电导率解,并通过数值模拟实例加以说明.本文的结果可为张量感应测井资料的视值解释提供更好的选择.

The improvement of the apparent value interpretation method for tensor induction well logging

The formation anisotropic conductivity can be detected by tri-axial Tensor Induction Well Logging(TIWL).Based on the low frequency approximation of TIWL response in a homogeneous,transversely isotropic conductive medium,Zhdanov et al.derived the analytic formula to extract the conductivity of the anisotropic formation,the borehole dip angle and tool azimuth from the response of TIWL.These can be used as the foundation of TIWL data interpretation.However,their equation for borehole dip angle has double solutions and the inverse solutions of the conductivity are not also the optimal approximation.In this article,we give not only a single value solution of borehole dip but also better approximative solutions of the conductivity.The theory is illustrated by numerical examples of TIWL.The results given in this paper can provide the better choice for TIWL apparent value interpretation.