海上多方位观测系统照明分析

Illumination analysis for offshore multi-azimuth seismic survey

海上多方位观测系统能够获得多方位角的地震信息,从而增强地震照明度,提高勘探精度。基于波前构建法计算模拟偏移振幅(SMA)强度,作为照明量对多方位观测系统的照明响应进行研究,为评价和优化多方位观测系统提供指导和依据。理论模型和实际地质模型照明结果表明,随着方位角个数的增加,多方位观测系统针对目的层的照明能量的连续性和均匀性变好,能够有效地改善单个窄方位角观测系统下的照明阴影区的照明效果,可广泛应用于海上复杂地质环境下的地震数据采集。

Multi-azimuth seismic survey is a new acquisition geometry,which can gain multi-azimuth seismic information,eventually strengthens seismic illumination and improves exploration precision.On the basis of 3D ray modeling by wavefront construction,simulated migration amplitude（SMA）intensity is calculated,which is regarded as the measure of illumination to study the responses of multi-azimuth survey,and provides guide for evaluating and optimizing multi-azimuth survey.The application results of the numerical model and actual geological model demonstrates that the illumination of the target strata collected by multi-azimuth survey had much better continuity and uniformity,improved the illumination intensity at the shadow area gathered by parallel geometries.So multi-azimuth survey is an ideal offshore seismic survey,and can be widely used in complex geological environments in the offshore exploration.