面向目标的叠前角度道集提取策略  

Extraction scheme for object-oriented prestack angle gathers.

作　　者：袁江华[1] 刘洪[1] 首皓[1] 秦月霜[2] 

机构地区：[1]中国科学院地质与地球物理研究所,北京100029 [2]中国石油大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《石油物探》2007年第4期334-338,共5页Geophysical Prospecting For Petroleum

基　　金：国家高技术研究发展计划(863计划)项目(2006AA09A102-08);国家自然科学基金项目(40674072)共同资助。

摘　　要：为解决三维叠前角度道集的生成和存储问题,在局部谐波分解思路的基础上,将二维情形下的角度道集生成技术推广到三维情形。方法的基本原理是:通过定义局部角度变换、波数和空间域滤波因子,给出入射波及散射波的角度域表达形式;利用上(下)行波的角度道集三角展开系数,结合相关成像条件,生成反射系数角度道集的三角展开系数体,并由指数映射,获得反射系数角度道集。在具体实现时,利用面向目标的大步长波场延拓,实现快速、准确,针对目标层的偏移成像,同时,在角度域计算谐波分解三角展开系数;采用炮域并行思路,将主节点和各节点的计算加以分解,以节省各节点中间环节的角度道集存储空间,各节点只计算三角展开系数,在主节点回收并生成系数数据体;然后,根据具体目标需求,输出相应的角度道集。由此,极大地减少了角度道集数据存储量,解决了计算效率及存储空间问题。利用中国东部某油田的三维地震资料对方法进行了测试,结果表明方法可行实用。To solve the problems of the generation and storage for 3-D prestack angle gathers,based on the idea of local harmonic decom- position,the 2-D angle gathers generation technology was extended to 3-D.The principles of this method are as follows.The expres- sions for incident wave and scattered wave in angle domain are presented through defining local angle transform and filtering fac- tors in wave-number domain and spatial domain.Utilizing the trig- onometric expansion coefficients of angle gathers for up-and down- going waves,together with relevant imaging conditions,the trigo- nometric expansion coefficients cube of reflectivity angle gathers is generated.Furthermore,with exponential mapping,reflectivity angle gathers are obtained.When coding the program,the research result of object-oriented large-step wavefield extrapolation is also resorted to realize the high efficient,accurate and target-aimed im- aging.Meanwhile,the trigonometric expansion coefficients of har- monic decomposition are calculated in angle domain.The program adopts shot domain parallel scheme where the computation for host-node and that for servant-nodes are separated so as to free servant-nodes from saving angle gathers in middle procedures. Thus,the main duty for servant-nodes is to compute trigonometric expansion coefficients,while that for host-node is to reclaim them and generate a coefficients cube.Then,according to specific de- mands for target profile or cube,corresponding angle gathers are formed.Thanks to the schemes above,rather less disk space is e- nough for generating angle gathers.So,the problems of computing efficiency and storage are solved.The result of test,with 3D seis- mic data from an oilfield in Eastern China,shows that this method is feasible and practical.

关 键 词：谐波分解 面向目标 叠前角度道集 大步长偏移 并行算法 

分 类 号：P631.4[天文地球—地质矿产勘探]