海上双正交宽方位地震勘探技术研究与实践

Research on and practice of offshore biorthogonal,wide azimuth seismic exploration technology

针对近海中深层复杂地质目标勘探面临的构造成像差、储层横向变化大等难题,在对渤海某靶区地震地质问题进行深入分析的基础上,开展了宽方位地震采集参数论证与优选,偏移距、方位角、叠加响应及DMO覆盖次数等观测系统属性的均匀性分析表明双正交宽方位采集优于常规海底电缆采集;同时,设计了点震源气枪阵列,使不同频率下各个方向的能量分布更加均匀。实际资料采集和初步处理效果表明,双正交宽方位采集达到了高覆盖次数和富角度照明的效果,因此宽方位地震勘探技术能大幅提高中深层勘探精度。

In view of the problems of poor structure imaging and large lateral reservoir variation experienced by exploration of mid-to-deep complex geological targets,and based on profound analysis on seismic and geological problems in a Bohai target area,the author carried out demonstration and optimization of wide azimuth seismic acquisition parameters. The analysis of the uniformity of geometry attributes,such as offset distribution,azimuth,stacked response and DMO coverages,etc.,shows that the orthogonal wide azimuth acquisition is superior to the conventional subsea cable acquisition. Also,a point-source air gun array is designed,so that the energy distribution in each direction is even more uniform at different frequencies. The actual data collection and preliminary processing results show that the biorthogonal wide azimuth acquisition achieves high folds and rich-angle illumination. Therefore,the wide-azimuth seismic exploration technology can greatly improve the accuracy of mid-to-deep formation exploration.