论文详情
页岩储层的开发主要依赖于水力压裂，因此有必要研究储层的岩石力学性质。利用地球物理方法分析岩石脆性特征、反演杨氏模量和泊松比对于页岩气的开发具有重要意义。基于贝叶斯理论，通过最小二乘构建反演方法对杨氏模量和泊松比进行直接反演，有效避免了常规AVO反演密度项的不稳定和参数转换过程中的误差积累，提高了反演结果精度。同时借助后验协方差矩阵，对反演结果进行了不确定性分析，发现其不确定性有明显的降低。利用反演得到的杨氏模量和泊松比，进一步计算目的层脆性指数(BI)，并通过微地震监测数据对预测结果进行验证，为寻找有利压裂区域提供重要的基础数据。应用实际资料预测的脆性结果与测井结果具有较高的一致性，显示了方法具有一定的应用推广前景。
Nowadays hydraulic fracturing is one of the main methods for reservoir reconstruction and the mechanical properties of the rock is the foundation for the design of reservoir fracturing.It is significant to analyze the brittleness of the rock for shale gas and inverse Young’s modulus and Poisson’s ratio.The inversion procedure based on Bayesian theory is to directly inverse the Young’s modulus and ratio of Poisson on Least-Square rule,which could avoid the uncertainty of density and the accumulation of errors during different parameters transformation in conventional Amplitude Versus Offset (AVO) inversion,with improvement of inversion’s accuracy.Meanwhile,the uncertainty of the inversion is also been analyzed by inspecting the posterior cross-correlation matrix.The brittleness index (BI) could be further calculated by Young’s modulus and Poisson’s ratio from the inversion,which could be verified by microseismic monitoring result and serves as an important indicator for favorable fracture zones.That the predicted brittleness from field seismic data is shown to be consistent with the well log means it has a great potential in application.
国家重点基础研究发展计划(973计划)课题(2011CB201002)和国家科技重大专项课题(2011ZX05014-001)共同资助。