基于各向异性岩石物理模型的页岩气储层横波速度预测  

Shear wave velocity prediction for shale gas reservoirs based on anisotropic rock physics model

作　　者：胡起 陈小宏[1,2] 李景叶[1,2] 

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)CNPC物探重点实验室,北京102249

出　　处：《石油物探》2014年第3期254-261,共8页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金项目(U1262207和41074098)资助

摘　　要：通过融合各向异性微分等效介质(DEM)理论和Brown-Korringa各向异性流体替换模型,建立了有机页岩各向异性岩石物理模型,提出了根据纵波速度反演岩石等效孔隙纵横比进行页岩气储层横波速度预测的方法。首先,利用各向异性DEM模型和Brown-Korringa模型建立有机页岩各向异性岩石物理模型,得到有机页岩纵、横波速度与密度、孔隙度、饱和度和矿物组分等参数之间的关系;其次,将岩石孔隙等效为具有单一孔隙纵横比的理想椭球孔,应用二分法来寻找最佳的等效孔隙纵横比使得理论预测与实际测量的纵波速度之间的误差最小;最后,将反演得到的等效孔隙纵横比代入到所建立的岩石物理模型中,构建横波速度。实验室岩样数据的应用试验结果表明,由纵波速度构建的横波速度与实测横波速度吻合良好,验证了基于各向异性岩石物理模型的有机页岩横波速度预测方法的有效性。By combining the anisotropic differential effective medium （DEM） theory with the Brown-Korringa anisotropic fluid substitution model,we presented an anisotropic rock physics modeling method for shear wave velocity prediction from the effective pore aspect ratio inverted from the P wave velocity in shale gas reservoirs.Firstly,by using the anisotropic DEM model and Brown Korringa model,we built a relationship among P-wave and S-wave velocity,density,porosity,saturation and mineral compositions,et al.Then,by assuming the porous rock containing spheroidal pores with a single pore aspect ratio,we applied the bisection method to find the best estimate for the effective pore aspect ratio by minimizing the error between theoretical predictions and experimental measurements of P-wave velocity.Finally,we estimated the S-wave velocity from the inverted effective pore aspect ratios.Experimental results of core data show that the predicted S-wave velocity from P wave velocity is in good agreement with the measured ones,which illustrates the validity of S-wave velocity prediction for shale gas reser voirs based on anisotropic rock physics model.

关 键 词：有机页岩 各向异性岩石物理建模 横波速度预测 DEM模型 Brown-Korringa模型 

分 类 号：P631.4[天文地球—地质矿产勘探]