基于偶极横波测井的低渗透砂岩气层识别方法

Identification of Low Permeability Sandstone Gas Reservoir Based on the DSI

鄂尔多斯盆地东部属典型的低孔隙度低渗透率储层,储集空间小、渗透性能差,电阻率和孔隙度资料受岩石骨架影响较大,流体对其响应特征贡献小,而偶极横波测井能获取真实的地层骨架及流体声波速度信息。利用斯伦贝谢公司DSI测井资料,通过弹性模量差比与纵波等效弹性模量差比、纵横波速比与波阻抗以及泊松比、体积压缩系数等弹性力学参数建立了气层识别指标,并在此基础上基于Biot-Gasmann理论提取流体因子建立了识别气层的标准。通过实际资料处理和试气资料成果验证,该方法在低渗透砂岩气层识别中具有较好的应用效果。

As a typical low porosity and low permeability reservoir,eastern ordos Basin retains small reservoir space,poor permeability,complex electrical resistivity and porosity data influenced by the rock matrix.Fluid makes little contribution to its response characteristics,but dipole shear wave logging can get real formation skeleton and fluid acoustic velocity information.Based on Schlumberger DSI logging data and the indicators,such as the relative ratio of elastic modulus,the longitudinal wave relative ratio of equivalent elastic modulus,the ratio of compressional wave velocity to shear wave velocity,the wave impedance,Poisson's ratio and the coefficient of compressibility,gas identification indicatorsare made up,and a gas reservoir fluid factor is extracted to establish gas identification standards based on Biot-Gassmann theory.According to actual data processing and gas test data,this method achieves good results in low permeability sandstone gas reservoir identification.