叠前时间偏移技术在深层断陷区地震成像中的应用  

Application of prestack time migration to seismic imaging of deep fault depression areas

作　　者：崔宝文[1,2] 王维红[3] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]大庆油田有限责任公司油藏评价部,大庆163453 [3]大庆油田有限责任公司勘探开发研究院,大庆163712

出　　处：《地球物理学进展》2010年第5期1703-1708,共6页Progress in Geophysics

基　　金：国家自然科学基金项目(41004057)资助

摘　　要：Kirchhoff积分叠前时间偏移应用波动方程的Kirchhoff积分解实现地下反射层的偏移问题,该技术应用所有偏移距的地震资料,能适应纵横向速度变化较大的情况,是复杂地区地震资料成像的较理想的方法.叠前时间偏移是对偏移处理和偏移速度修改的一个迭代过程,偏移速度的精度直接影响到偏移效果.对大庆油田古龙断陷某工区的三维地震资料,应用叠前时间偏移技术进行成像处理,对于埋深较大的目的层,断陷结构复杂,介质的各向异性较为严重,所以应用考虑各向异性参数的速度修改公式,得到较为精确的偏移速度体,进而保证偏移CRP道集拉平,得到成像良好的偏移数据体.实际地震数据偏移处理结果表明叠前时间偏移技术可对复杂构造的地震数据准确成像,可在古龙地区断陷地层勘探中推广应用.The imaging in prestack time migration （PSTM） is realized via application of Kirchhoff integration solution of wave equation, which uses all offset seismic data, and can be applied effectively to complex exploration areas in which velocity varie strongly both along the radial and vertical direction. So PSTM is a better migration algorithm for imaging complex geological structure. PSTM is an iterative process for seismic data migration and improvement of migration velocity. The migration quality of seismic data is determined by the precision of migration velocity. Prestack time migration is applied to the 3D seismic survey in the Gulong fault depression in Daqing Oilfield. The improved velocity formula is used for deep formation imaging in which velocity anisotropy term is taken into consideration. Another reason is that the fault depression is complex and the anisotropy is strong. The precision of migration velocity is high, and the events in migration Common Reflection Point（CRP） gathers are flatten. It means that the PSTM imaging result is good. Prestack time migration process for field seismic data demonstrates that PSTM approach can be applied to seismic data imaging in the Gulong fault depression with deep formation.

关 键 词：叠前时间偏移 Kirchhoff积分 速度各向异性 高精度速度分析 古龙断陷 

分 类 号：P631[天文地球—地质矿产勘探]