水平井各向异性地层双感应测井响应数值模拟

地层电阻率是影响油气评价的重要参数,水平井中常利用感应测井确定地层电阻率,由于水平井与直井测量环境有较大差异,响应方式势必与直井不同。基于三维数值模式匹配法模拟了水平井各向异性地层双感应的测井响应,分析了地层各向异性系数、围岩层厚、地层界面距离、泥浆侵入、不同地层对比度以及围岩和各向异性对各双感应测井响应的影响。模拟结果表明:目的层高阻时,水平井中双感应受围岩影响较大,低阻时受围岩影响较小;当目的层较薄时,围岩影响要大于各向异性影响;水平井中双感应幅度差主要受围岩影响,各向异性较小时,其幅度差可忽略。

Dual induction logging numerical simulation of anisotropic formation in horizontal wells

Formation resistivity is the key parameter, which has an effect on the evaluation of oil and gas, we usually use the induction logs to calculate the formation resistivity in horizontal wells, as the measurement environment is different between horizontal wells and vertical wells, the ways of responsing should be different too. Based on the three dimensional numerical simulation of matching, we simulated the dual induction logging response of horizontal wells in anisotropic formations, and analysised the impact on which anisotropy coefficient, thickness of rock, interface distance of formation, mud invasion, the contrast degree of different rock formations ,surrounding rock and heterogeneity has for each dual induction logging response. Simulation results show that: when the target layer has high resistance, the dual induction logging response in horizontal wells are much influenced by surrounding rock, instead, the influences are small; also when the target layer is much thin, surrounding rock has the greater influence than the heterogeneity; the amplitude difference of dual Induction in horizontal wells are mainly affected by the surrounding rock, when the heterogeneity is not strong, the affects can be ignored.