横波预测技术在苏里格气田储层预测中的应用

横波资料的缺乏严重制约了苏里格气田A区储层岩性、物性及流体识别等工作的开展,以往横波预测结果精度低,识别能力差,已不能满足储层预测需求。为此,基于地质、钻井、测井、地震等资料,针对苏里格气田A区上古生界砂泥岩地层的实际情况,确定了构建Xu-White模型所需的各项岩石物理参数,进行了横波预测研究,结合岩石物理分析、叠前弹性参数反演等技术实现由点到面的储层预测,获得的预测横波曲线与实测横波曲线吻合度较高。结果表明:①使用纵横波速度比、剪切模量以及拉梅模量/剪切模量、体积模量/剪切模量可有效划分砂、泥岩,利用拉梅模量/剪切模量—纵波阻抗、体积模量/剪切模量—纵波阻抗、泊松比—纵波阻抗交会等是识别流体的有效手段;②利用文中方法预测的盒8段储层、气层厚度与实钻数据误差小,储层分布与该区地质规律一致。

Reservoir prediction based on shear wave in Sulige Gas Field

Reservoir lithology and properties, and fluid identifications in the area A, Sulige Gas Field have had huge difficulties due to the lack of shear wave velocity. Inaccurate shear wave velocity prediction leads to poor reservoir characterization. We first determine rock physical parameters based on geological, drilling, logging, and seismic data for Xu-White model building. Then we predict shear wave velocity in the study area, and the predicted shear velocity is well matched with logging data. Finally we carry out reservoir identification with rock physics analysis and prestack seismic inversion. The following observations are obtained: ①Sandstone and shale can be classified with P- and S-wave velocity ratios, shear modulus, lamda/shear modulus, and bulk modulus/shear modulus; and fluid can be identified with the crossplots of lame modulus/shear modulus vs P-wave impedance, bulk modulus/shear modulus vs impedance, and Poisson's ratio vs P-wave impedance. ②Gas layer thickness prediction, reservoir identification and reservoir distribution prediction with the proposed approach are well matched with drill data and real geological conditions.