VSP逆时偏移及其存储策略研究  

VSP reverse time migration and its data storage strategy

作　　者：王维红[1] 郭雪豹[1] 石颖[1,2] 刘诗竹[1] 

机构地区：[1]东北石油大学地球科学学院,黑龙江大庆163318 [2]黑龙江省普通高校科技创新团队“断层变形、封闭性及与流体运移”,黑龙江大庆163318

出　　处：《石油地球物理勘探》2015年第1期77-83,16,共7页Oil Geophysical Prospecting

基　　金：国家“863”计划项目(2012AA061202);国家自然科学基金项目(41474118)联合资助

摘　　要：在逆时偏移算法中,应用常规的随机边界方法虽可节约存储空间,但浅层常伴有随机噪声。应用PML边界方法虽可改善上述状况,却又面临地震波场存储的压力。为此,本文采用优化系数的高阶有限差分方法实现VSP数据逆时深度偏移,采用拉普拉斯去噪方法压制低频噪声,并兼顾考虑精度和存储,在PML边界震源波场正传过程中保存部分波场,进而利用保存的信息与检波点波场同步反传,不仅可有效地节约存储空间,也确保了替代波场信息的可靠性。断层模型测试表明,本文方法能够以低存储实现高精度的VSP逆时偏移,相比于地面地震偏移,断层成像更清晰、准确。Although conventional random boundary methods can save storage space in reverse time migration algorithm,random noise often exists at shallow layers.PML boundary method can improve the situation,but suffer from seismic wave field storage problem.Here we adopt the high order optimization coefficient finite difference method to realize reverse-time depth migration of VSP data,and use Laplace denoising method to suppress low frequency noise.Considering both precision and storage,we store a part of source wave field forward modeling with PML boundary method,which is used in source wave field reverse extrapolation with receiver wave field.This approach can not only save storage space,but also ensure the reliability of the alternative wave field information.Fault model tests indicate that the proposed approach can be implemented with a low storage and high precision of VSP reverse time migration.Fault imaging is more clear and accurate than that of surface seismic migration.

关 键 词：VSP 逆时偏移 随机边界 PML边界 

分 类 号：P631[天文地球—地质矿产勘探]