叠前深度偏移技术在北黄海盆地东部坳陷中的应用  

Application of Pre-stack Depth Migration in the Eastern Depression of the North Yellow Sea Basin

作　　者：杜民[1,2] 薛花[1,2] 王衍棠 万晓明[1,2] 简晓玲[1,2] DU Min;XUE Hua;WANG Yantang;WAN Xiaoming;JIAN Xiaoling(Key Laboratory of Marine Mineral Resources,Ministry of Land and Resources,Guangzhou 510075,China;Guangzhou Marine Geological Survey,Guangzhou 510075,China)

机构地区：[1]国土资源部海底矿产资源重点实验室,广州510075 [2]广州海洋地质调查局,广州510075

出　　处：《华南地震》2018年第1期17-23,共7页South China Journal of Seismology

基　　金：国家自然科学基金项目"北黄海盆地构造热机制与成烃效应"(41302100)

摘　　要：北黄海盆地东部坳陷地质构造复杂,断裂特征及地层接触关系不清楚,横向凹陷与隆起的构造起伏大,造成速度横向变化剧烈,由时间偏移得到的地质成像不准确,因此必须通过深度偏移得到地震数据的地质成像。从研究区复杂构造地质背景出发,阐述了叠前深度偏移原理和技术路线,对该区三维地震资料分别应用了Kirchhoff积分法叠前深度偏移和逆时叠前深度偏移两种算法。从时间偏移和深度成像效果的对比可以看出,深度偏移较时间偏移更能够表征地下真实成像位置,深度偏移在陡倾角成像上更加合理、陡倾角连续性增强,波组特征明显,尤其在断面成像上更加清晰;从两种深度偏移算法成像效果的对比可以看出,逆时深度偏移算法在陡倾角复杂构造区和深层反射层段的成像效果上较Kirchhoff积分法更佳,前者成果数据的保真性更高,能为叠前反演提供较好的原始资料。The geological structure is complicated in eastern Depression of the North Yellow Sea Basin, in which the fault characteristics and stratigraphic contact relationship are not clear. The structure relief in Eastern Depression is obvious between sag and uplift causing severe lateral velocity variation, and the imagining results obtained by time migration are inaccurate. Therefore, the better imaging profiles must be obtained by application of depth migration in the study area. Based on the complex geological background of the study area, the principle and technical route of pre-stack depth migration are expounded, and two migration methods are usedto process the 3 D seismic data, namely the Kirchhoff integral and the reverse-time pre-stack depth migration.By comparison of the effects of time and depth migration, it reveals that depth migration results represent the real imaging position of the ground, show more reasonable in steep dip situation with enhancement of consistency, have more obvious characteristics of wave group in depth migration profiles, and get the more distinct imaging of fault surface. By comparison of the effects of two different pre-stack depth migration, it shows that reverse-time pre-stack depth migration gains better image in steep dip angle complex tectonic area and deep reflector segment than Kirchhoff integral pre-stack depth migration, which also gets higher data fidelity, so this migration method would provide preferable basic data for pre-stack inversion.

关 键 词：北黄海盆地 东部坳陷 Kirchhoff积分法叠前深度偏移 逆时叠前深度偏移 

分 类 号：P631.4[天文地球—地质矿产勘探]