各向异性叠前时间偏移在复杂断块中的应用  

Application of anisotropic Pre-stack time migration to complex fault area

作　　者：万欢 李添才[1,2] 方中于 赫建伟 刘金朋 丘斌煌 

机构地区：[1]中海油能源发展特普地球物理分公司,湛江524057 [2]吉林大学地球探测科学与技术学院,长春130026

出　　处：《地球物理学进展》2011年第1期207-213,共7页Progress in Geophysics

基　　金：国家重大科技专项子专题"莺琼盆地高温高压区高精度地震资料采集处理技术研究2008ZX050000230401"资助

摘　　要：在构造复杂的地区,地震速度横向变化较大,常规时间偏移方法已无法完成复杂断块地区的正确成像,必须采用叠前偏移成像技术,来解决复杂构造地震资料的成像问题.与叠后偏移相比,叠前时间偏移有更高的成像精度、信噪比和更好的波组特征.各向异性叠前时间偏移将层速度代替叠前时间偏移中的均方根速度,在一定程度上解决了地下地质体的复杂构造问题.本文针对VTI各向异性介质建立精细的速度模型与各向异性场,通过试验进行各向异性参数的选择,对Kirchhoff弯曲射线时间偏移技术进行理论和实际操作上的简单介绍.通过对海上一个断块非常发育的三维数据体进行偏移处理研究,形成了针对该区的叠前时间偏移处理方法和流程.应用各向异性叠前时间偏移,改善了地震成像道集和剖面质量,提高了成像质量.Lateral velocity varied strongly in complicated structural areas. Therefore, it is hard to image the complex fault-block areas using conventional time migration. Pre-stack time migration can raise the imaging accuracy,increase signal to noise ratio and make wave group characteristics of every reflection zone more clear, so pre-stack time migration technique is applicable to image complex fault-block areas. Complex fault-block areas will be imaged accurately by replacing root-mean-square velocity of pre-stack time migration by interval velocity of anisotropic pre- stack time migration. In this paper, a refined velocity model and anisotropic field of VTI anisotropic media are built, the anisotropic parameter selected by experiment is studied, and the theory and practical operation of Kirchhoff bending-ray time migration technique are introduced briefly. Through the research of 3-D marine data in complex fault-block areas, the theory and process of pre-stack time migration is formed. By using anisotropic pre-stack time migration, the quality of seismic trace gathers and sections and the imaging accuracy have been improved.

关 键 词：复杂断块 KIRCHHOFF叠前时间偏移 叠前去噪 各向异性场 

分 类 号：P631[天文地球—地质矿产勘探]