倾斜层位偏移规律研究

Research on offset law of tilted layer

层状介质模型是对实际地质情况较为准确的近似。而在实际的数据处理过程中,以等效均匀介质代替层状介质,波传播的几何路径、介质速度的差别会使对倾斜界面位置的判断偏离实际情况。针对设计的理论模型和从测井数据提取的实际介质模型,笔者运用几何射线理论和波场数值模拟技术,定量计算并提取了层状介质模型和等效均匀介质模型两种情况下反射点在时间和空间上的偏移量。结果证明,等效均匀介质模型近似会造成对倾斜界面位置的判断不准确;准确的速度模型是偏移归位研究的关键,应尽量使用由地震测井资料求得的瞬时速度。

Layered media model is a more accurate approximation of actual geological conditions.However,in data processing of actual production,if we use equivalent homogeneous media instead of layered media,different geometric path of wave propergation and medium velocity will make the judgment of dipping interface location deviate from the actual condition.According to theoretical model and actual media model extracted from logging data and by using geometrical ray theory and wave field numerical modeling techniques,we quantitatively calculate and extract the offset of reflection points in both time and space,of both layered media model and equivalent homogeneous media.The result shows that using equivalent homogeneous media will cause the judgement of dipping interface location inaccurate.Thus,using accurate velocity models is the key for the study of migration homing,and better use of instantaneous velocity obtained from seismic logging data is requested.