横波各向异性分析方法及其在复杂储层中的应用  

S-wave anisotropy analysis method and its application on complex reservoir

作　　者：魏周拓[1] 范宜仁[1] 陈雪莲[1] 邓少贵[1] 白博[1] 

机构地区：[1]中国石油大学(华东),山东青岛266555

出　　处：《石油物探》2011年第3期275-280,6,共6页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金(40804020)项目;中国石油天然气集团公司重大科技项目(2008A-2704);中央高校基本科研业务费专项资金(09CX04001A)联合资助

摘　　要：裂缝和井周的不均衡地应力均可引起地层的横波各向异性。分析井周地层的横波各向异性特征,可以指示地层的裂缝和不均衡地应力信息。从各向异性地层中的横波分裂现象入手,基于波形反演理论,利用正交偶极子阵列声波资料,分析和评价了裂缝性和低孔、低渗储层的横波各向异性,利用计算得到的各向异性参数评价了裂缝性地层中裂缝的发育程度、方位以及低孔、低渗地层的地应力分布状态。利用单极子横波各向异性大小和快、慢弯曲波波形频散曲线关系,分析了引起横波各向异性的原因。结合常规测井资料、岩心及FMI成像资料对分析结果进行了验证和对比,两者吻合得较好。应用结果表明,横波各向异性参数可以有效地评价裂缝的发育程度、走向及有效性,并能准确地确定地应力分布状态和最大水平应力方位。Fractures and wellside unequal in-situ stress may lead to the S-wave anisotropy of formations.The analysis of the characteristics of S-wave anisotropy for wellside formation can indicate the fractures and unequal in-situ stress.Starting from S-wave splitting in the anisotropic formation,based on waveform inversion theory,we used the orthogonal dipole array acoustic data to analyze and evaluate the features of fractures and the S-wave anisotropy of low-porosity & low-permeability reservoir.Then,the calculated anisotropic parameters were used to evaluate the development and azimuth of fractures and the distribution of in-situ stress in low-porosity & low-permeability formation.Meanwhile,the relation between S-wave anisotropy of monopole and waveform dispersion curve of fast and slow bending wave was utilized to analyze the cause for S-wave anisotropy.Finally,combined with conventional logging data,core and FMI imaging data,the analysis result was verified and contrasted, and the result shows the two matches well.Application indi- cates that S-wave anisotropy parameters can effectively evaluate the development,trend and feasibility of fractures,exactly identify the distribution of in-situ stress and the azimuth of maximum horizontal stress.

关 键 词：横波各向异性 波形反演 裂缝 低孔 低渗地层 地应力 

分 类 号：P631.4[天文地球—地质矿产勘探]