裂缝性储层阵列声波成像测井响应模拟及速度频散特征研究  

Study on the Numerical Simulation of Array Sonic Logging Responses and Their Velocity Dispersion Characteristics in Fractured Formation

作　　者：罗辉 沈金松 张文学 孙帅 张喆安 王谦 蔺学旻 LUO Hui;SHEN Jinsong;ZHANG Wenxue;SUN Shuai;ZHANG Zhe’an;WANG Qian;LIN Xuemin(The Fourth Oil Development Plant,North-West Oil Field Corporation,Kuche 841100,China;College of Geophysics,China University of Petroleum,Beijing 102249,China;Research Institute of Exploration and Exploitation,North-West Oil Field Corporation,Wulumuqi 830011,China)

机构地区：[1]中石化西北油田分公司采油四厂,新疆库车841100 [2]中国石油大学地球物理学院,北京102249 [3]中石化西北油田分公司勘探开发研究院,乌鲁木齐830011

出　　处：《CT理论与应用研究（中英文）》2024年第6期747-760,共14页Computerized Tomography Theory and Applications

基　　金：国家自然科学基金(非常规储层水力压裂电磁监测方法与导电支撑剂反演成像研究(42074127))。

摘　　要：为分析裂缝性储层中裂缝发育带对阵列声波测井响应的影响,本文采用交错网格有限差分算法实现孔弹介质阵列声波测井波列响应的数值模拟。通过对模拟波形速度频散信息的提取,总结裂缝发育带与扩径井段不同模式波的吸收衰减与速度频散响应特征的差异性。首先基于Biot孔弹介质模型导出柱坐标下弹性波的速度-应力方程;其次,用交错网格有限差分方法对孔弹波动方程进行离散化,为提高模拟算法效率与精度,使用高阶差分格式与NPML;最后,基于含倾斜裂缝带模型与井壁坍塌地层模型的响应模拟,用前后向振幅相位估计法分析阵列声波的波形幅度相位响应特征与速度频散的差异性。结果表明,低速裂缝带纵横波波场时差会增大,且衰减幅度随裂缝带倾角变化;井壁塌陷在径向与轴向上扩大时,会增强斯通利波与伪瑞利波衰减。声波纵横波时差、速度频散与幅度衰减均可反映一定的裂缝带特征,这些影响对评价和开发裂缝性储层具有重要意义。To understand the effects of fractured formation on the responses of array sonic logging,the wave propagation of array acoustic logging was simulated based on the staggered grid finite difference method and poroelastic theory.Methods of velocity dispersion analysis and attenuation estimation were carried out on simulated sonic waveforms,and the differences of velocity dispersion and wave amplitude attenuation among these wave modes were summarized.First,the velocity-stress equation in cylindrical coordinates was deduced for the Biot poroelastic model.Next,the velocity-stress wave equation was discretized by using the staggered grid finite difference method.Furthermore,the higher order finite difference format and nearly perfect match layer(NPML)were adopted to improve the efficiency and accuracy of the finite difference method.Finally,simulated sonic waveforms in formation models with a tilted fracture zone and collapsed interval were applied to the velocity dispersion analysis by using forward and back amplitudes and the phase estimation method.The results show that the time difference of the P and S wave field in the low-velocity fracture zone increases and that the attenuation amplitude changes with the dip angle of the fracture zone.The attenuation of Stoneley waves and pseudo-Rayleigh waves is enhanced when the shaft collapse expands in the radial and axial directions.The time difference of acoustic waves,velocity dispersion,and amplitude attenuation can reflect the characteristics of the fracture zone,which is of great significance to the evaluation and development of fractured reservoirs.

关 键 词：裂缝性储层 阵列声波测井 孔隙弹性介质模型 交错网格有限差分 速度频散 

分 类 号：P631[天文地球—地质矿产勘探] TE19[天文地球—地质学]