基于岩石物理诊断的横波速度估算方法

Shear wave velocity estimation based on rock physics diagnosis

横波速度是进行叠前地震反演和叠前地震属性分析的必要资料,但目前绝大多数钻井都缺少横波测井资料。本文通过常数胶结模型分析了岩石速度的影响因素,岩石固体部分的黏土成分、孔隙度、胶结分数、沉淀模型以及配位数等参数都会影响计算结果,流体部分的饱和度、气油比以及流体混合方式也会影响计算结果。结合Gassmann方程和常数胶结模型,本文将固结分数作为反演过程中的可调因子,利用岩石的纵波速度反演得到岩石的胶结分数值,进而进行横波速度预测。通过对实际测井数据的处理,证明该方法能准确有效地预测出横波速度。

S-wave velocity is critical information for prestack seismic inversion and prestack seismic attribute analysis.But S-wave velocity in logging data usually is lacked.We propose in this paper S-wave velocity estimation based on rock physics diagnosis.First we analyze the factors affecting rock velocity based on the constant cement model.Both the solid part such as clay composition,porosity,precipitation model and coordination number,and the fluid part such as saturation,gas-oil ratio,and fluid mixture affect calculation.Then using Gassmann equation and the constant cement model and taking score of consolidation as the adjustable factor in the inversion process,we obtain rock cemented fractional value by rock P-wave wave velocity inversion.Finally we carry out shear wave velocity estimation.Log data processing tests prove that the proposed method can accurately and efficiently predict the shear wave velocity.