基于角道集的井约束层析速度反演  

Tomography velocity inversion by well constraint based on the angle domain common imaging gathers

作　　者：秦宁[1] 李振春[1] 杨晓东[2] 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266555 [2]中石化胜利石油管理局石油开发中心,山东东营257000

出　　处：《石油地球物理勘探》2011年第5期725-731,836+662,共7页Oil Geophysical Prospecting

基　　金：国家自然科学基金(40974073);国家863课题(2007AA060504);中国石油大学(华东)研究生创新基金项目资助

摘　　要：本文研究的走时层析方法,是在角度域共成像点道集(ADCIGs,简称角道集)的基础上获取旅行时差,并通过井约束控制层析反演的精度。此法实现的关键步骤为:①利用叠前深度偏移剖面上拾取的层位界面生成初始层析速度模型;②按照选定的角度范围抽取共成像点道集,并求取各层位的旅行时差;③求取共成像点对应的灵敏度矩阵;④建立反演方程组,并加入正则化和井约束反演慢度更新量;⑤依据共成像点道集中的同相轴拉平程度判断所求速度的精度是否达到要求。理论模型试算及实际地震资料处理结果均表明:该方法易于实现,不必考虑复杂的反射问题,每一步迭代都是在前一步深度偏移的基础上进行速度场的更新,能够得到精度较高的速度场。A travel-time tomography method proposed in this paper mainly gets travel-time residual on the basis of angle domain common imaging gathers(ADCIGs) and controls the precision of tomography inversion by well constraint.The key implementation steps are as follows: 1.Build the initial tomography velocity model using a layer interface picked from pre-stack depth migration;2.Get ADCIGs according to selected angle range and calculate the travel-time residual of each layer;3.Calculate the sensitivity matrix corresponding to the ADCIGs;4.Establish the inversion equation systems by adding the regularization and well constraint to inverse the slowness update;5.Determine if the velocity precision meets the demand or not through the flatten degree of ADCIGs events.The travel-time tomography results of model dataset and filed dataset have proved that this method is easy to carry out,without considering complex reflection problem.And the velocity updates of every iteration are obtained based on pre-stack depth migration of previous step,which can achieve velocity field with high precision.

关 键 词：角道集 层析速度分析 井约束 正则化 走时层析 

分 类 号：P631[天文地球—地质矿产勘探]