准噶尔盆地南缘近地表方位各向异性特征及地震成像  

Near‑Surface Azimuthal Anisotropy and Seismic Imaging in the Southern Margin of Junggar Basin

作　　者：罗勇[1] 谭佳[1] 杨晓海[1] 窦强峰 刘宜文[1] LUO Yong;TAN Jia;YANG Xiaohai;DOU Qiangfeng;LIU Yiwen(Geophysical Institute,Research Institute of Exploration and Development,Xinjiang Oilfield Company,PetroChina,Urumqi,Xinjiang 830013,China)

机构地区：[1]中国石油新疆油田分公司勘探开发研究院地球物理研究所,乌鲁木齐830013

出　　处：《新疆石油地质》2021年第1期100-106,共7页Xinjiang Petroleum Geology

基　　金：国家科技重大专项(2016ZX05003-005)。

摘　　要：准噶尔盆地南缘安集海背斜近地表非均质性强,岩性剧变,风化层速度变化大,复杂的表层激发接收条件改变了地震波传播的路径和速度,产生严重的近地表方位各向异性,导致有效地震波无法同相叠加成像,严重影响复杂构造的成像精度,是地震成像首先应该解决的问题。通过分析原始单炮初至走时特征,结合野外地质露头和卫星图,分析了动、静校正后的地震道集与炮点、检波点的对应关系,并与近地表各类冲沟、介质岩性进行紧密关联;通过分方位动、静校正及分方位加权叠前时间偏移成像处理,构建了不同方位的加权系数场,叠前时间偏移成像中“画弧”现象得到压制,成像效果明显改善,利用叠前时间偏移成像结果有效落实了安集海背斜中、下组合圈闭特征。The Anjihai anticline in the southern margin of the Junggar basin is a typical complex oil exploration area where the near‑surface heterogeneity is very strong,lithology changes fiercely,and the velocity of the weathered layer changes greatly.The complex near‑surface shooting and receiving conditions change the path and velocity of seismic waves and result in serious near‑surface azimuthal anisotropy,making effective seismic waves(events)not be superimposed.The accurate imaging of complex structure is the first problem to be solved in seismic processing.This study analyzed the characteristics of the first arrivals of original source points,and described the correspondence between gathers after NMO/static correction and source and receiver points based on geological outcrops and satellite images,and then built the close relationship with various gullies and near‑surface medium lithology,and finally established the weighted coefficient fields of different azimuth through azimuthal NMO/static correction and azimuthal weighted pre‑stack time migration imaging,so that the arcing phenomenon in pre‑stack time migration can be obviously suppressed,and the final migration imaging quality can be significantly improved.Using the results of pre‑stack time migration,the middle and lower trap combinations in the Anjihai anticline have been effectively identified.

关 键 词：准噶尔盆地 安集海背斜 方位各向异性 地震成像 叠前时间偏移 地质露头 卫星图 加权系数 

分 类 号：P631.443[天文地球—地质矿产勘探]