应用模型正演方法分析观测系统对复杂构造区成像的影响

Influences of acquisition geometry on complex structure imaging with forward modeling

针对地震勘探中的复杂地表及复杂构造区,设计了一种有效的观测系统方案,以期改善复杂构造区地震成像质量。根据中国西部某探区的地质结构特征建立数学模型,通过声波波动方程正演模型数据,得到不同的野外观测系统参数的地震数据记录,进行叠前偏移成像处理,最终对比分析不同观测系统参数对地震叠前偏移成像质量的影响。研究结果表明,在道密度不变的条件下,宽方位、炮检点均匀对称分布的观测系统更有利于叠前偏移成像。同时通过应用实际地震资料对比分析,进一步证明了宽方位三维观测系统对于解决复杂构造成像问题具有优势。

The purpose of this paper is to develop effective acquisition geometry in order to improve data imaging for difficult seismic exploration areas with complicated structures and rough surface topography.First a geological model is built based on geological structure characteristics in western exploration area.Then seismic data are obtained with different geometries by forward modeling,and imaged with prestack migration.It is found that the geometries with wide azimuth,uniform and symmetrical spatial sampling of both source and receiver can improve prestack migration imaging if the trace density is same.With field data analysis,it is also confirmed that the wide azimuth geometry can improve complex structures imaging.