起伏地表Kirchhoff积分法叠前深度偏移方法研究与应用  

Kirchhoff Integral PSDM for Rugged Topography： Technology and Applications

作　　者：刘少勇[1] 王华忠[1] 张兵[1,2] 

机构地区：[1]同济大学海洋与地球科学学院反射地震学研究组RSG [2]中国石化石油物探技术研究院

出　　处：《岩性油气藏》2010年第F07期49-54,共6页Lithologic Reservoirs

基　　金：特别感谢中国石化石油物探技术研究院和胜利油田物探院对本课题的支持.

摘　　要：地表起伏、近地表速度横向变化剧烈所引起的道间时差大、数据信噪比低是中国西部和南方山前带地区地震勘探的典型问题，这2个问题都与地表高程起伏变化大密切相关。基于水平地表的地震数据处理流程不能满足此类探区地震资料处理的要求．为此、文中将三维最短旅行时计算方法推广到了起伏地表条件。通过对道间时差的高低波数分量的分析，认为选择适当光滑的成像基准面来消除或减弱高波数道间时差对叠前成像的影响，中低波数部分在后续的叠前偏移剩余速度分析中可加以控制。基于此，文中提出了一套起伏地表条件下Kirchhoff积分法叠前深度偏移处理流程。理论模型分析和实际观测数据的处理给出了很好的偏移结果．证明了上述流程的合理有效性。Seismic exploration in mountainous region in the west and south of China is faced with two typical problems, significant trace-to-trace moveout and low S/N ratio, which are caused by rugged topography and severe lateral velocity variation at near surface. Both of the problems are closely related to the great difference of surface elevation. Seismic data processing method on the basis of horizontal surface is not applicable to this exploration area. [n this paper, the calculation of shortest 3D travehime is extended to be suitable for rugged topography. Based on analysis on high and low wave number components of trace-to-trace moveout, a suitable and smooth imaging datum is selected to eliminate or reduce the influence of trace-to-trace moveout of high wave number on pre-stack imaging. For medium to low wave number, it is controlled by subsequent pre-stack migration residual velocity analysis. Based on it, a new Kirchhoff integral pre-stack depth migration （PSDM） processing method for rugged topography is introduced. Processing for theoretical model data and real observation data gives good migration results, which proves the effectiveness of this method.

关 键 词：起伏地表 低信噪比 道间时差 叠前深度偏移 

分 类 号：P631.414[天文地球—地质矿产勘探]