基于岩石物理的页岩储层各向异性表征

Shale reservoir anisotropic characterization based on rock physics

针对罗家地区A井测井数据,应用Backus平均方法将模型从测井尺度粗化至地震尺度,应用各向异性传播矩阵模拟页岩含油储层的地震AVO响应,并结合实际地震资料进行井震标定;基于VTI介质反射系数理论公式进行VTI介质参数AVO反演,并应用井中岩石物理反演结果进一步计算页岩含油储层的裂缝空间分布。结果表明:(1)随着模型中各向异性参数ε数值的增大,远炮检距反射振幅逐渐减小;(2)由地震反演得到的各向异性参数和水平缝密度与岩石物理的计算结果一致,由反演得到的水平缝的空间分布与油气产量具有相关性,证明了反演方法的有效性。

Based on Well A data in Luojia area,we use Backus averaging method to upscale well data to seismic scale,and simulate seismic AVO response with the anisotropic propagator matrix.Then we carry out well-to-seismic calibration with combination of seismic data.We put forward the AVO inversion algorithm for calculating VTI parameters based on VTI medium reflection coefficient theoretical formula.With the result of rock physics inversion in well,we obtain the spatial distribution of fractures in shale oil reservoir.The following understanding are obtained:A.When the value of anisotropic parameterεin the model increases,the reflection amplitude at far offsets decreases gradually;B.Anisotropic parameters and the horizontal fracture density calculated by the seismic inversion are accord with the result obtained by rock physics.And the inverted spatial distribution of horizontal fractures is associated with the production of oil and gas,which proves the validity of the inversion method.