砂体尺度及埋深对AVO特征影响规律的地震物理模拟研究  

Seismic physical modeling analysis of the influence of sand scale and depth on AVO characteristics

作　　者：司文朋 闾晨[1,2] 王莹 SI WenPeng;LÜChen;WANG Ying(SINOPEC Geophysical Research Institute Co.,Ltd.,Nanjing 211103,China;Sinopec Key Laboratory of geophysics,Nanjing 211103,China)

机构地区：[1]中石化石油物探技术研究院有限公司,南京211103 [2]中国石化地球物理重点实验室,南京211103

出　　处：《地球物理学进展》2023年第3期1161-1168,共8页Progress in Geophysics

基　　金：国家自然科学基金企业创新发展联合基金(U19B6003-004);中国石化科技攻关项目(P21010)联合资助。

摘　　要：河流相碎屑岩储层大多面临着河道砂体厚度薄、宽度窄、不同构造部位的天然气富集程度差异明显等难题,利用AVO特征进行甜点预测时会受到多种因素的影响.与数值模拟正演方法相比,地震物理模拟能够更加真实的展示地震波在复杂地区传播的动力学特征.为了明确砂体厚度、宽度及埋深对AVO特征的影响规律,在满足物理模拟等效介质条件的前提下,分别构建了不同厚度、不同宽度砂体物理模型,并在不同埋深情况下进行了多次覆盖实验数据采集,提取叠前数据进行了AVO响应特征分析.物理模型结果表明,砂体厚度会导致叠前的调谐效应,AVO响应随砂体厚度增大呈现先增大、后缩小、最后稳定的趋势,埋深对不同厚度砂体的AVO响应规律无影响.砂体宽度在达到特定数值后AVO特征稳定不变,小于此数值时呈现缩小趋势;不同宽度砂体的AVO响应特征与埋深有关,砂体埋深越深,就需要更大的宽度才能使AVO响应特征达到稳定状态.使AVO特征达到稳定状态的砂体宽度与该埋深时的菲涅尔直径保持一致.通过物理模型砂体AVO特征的变化规律分析,能够为实际含气砂岩叠前预测提供一定的基础认识.The fluvial facies clastic rock reservoirs are mostly faced with problems such as thin thickness and narrow width of sand bodies,and obvious differences of gas enrichment in different structural parts.The sweet spot prediction using AVO characteristics may be affected by many factors.Compared with the numerical simulation forward method,the seismic physical simulation can more truly show the dynamic characteristics of seismic wave propagation in complex areas.In order to clarify the influence of sand thickness,width and burial depth on AVO characteristics,on the premise of satisfying the equivalent medium conditions of physical simulation,the physical models of sand with different thickness and width were constructed respectively,and the data of multiple coverage experiments were collected under different burial depths,prestack data were extracted for AVO response characteristics analysis.The results of physical model show that the thickness of sand body will lead to the tuning effect.The AVO response increases first,then decreases,and finally stabilizes with the increase of sand thickness.The burial depth has no effect on the AVO response of sand bodies with different thickness.The AVO response characteristics of sand with different widths are related to the burial depth.After the sand body width reaches the Fresnel diameter,AVO characteristics are stable,and when it is less than this value,it shows a decreasing trend The deeper the burial depth of sand bodies,the larger the width is required to make the AVO response characteristics reach a stable state.The analysis of AVO characteristics of physical model sand can provide basic knowledge for the prestack prediction of actual gas bearing sandstone.

关 键 词：砂体 尺度 埋深 AVO特征 地震物理模拟 

分 类 号：P631[天文地球—地质矿产勘探]