双船双方位角地震探测技术方法及应用效果

摘要

In Dongsha slope of the South China Sea, shallow fracture and reefs are numerous. Shallow Cenozoic is composed of carbonate rocks. The internal structure of deep Mesozoic is complex, with a lot of fracture. The conventional single vessel narrow azimuth seismic section shows poor reflection quality in deep sea. Dual vessels can be used to design flexible observation geometry, such as dual-azimuth seismic exploration. For the same reflection point lighting, this method of dual-azimuth seismic exploration is better than the narrow azimuth detection beneath the high acoustic velocity layer and the steep dip angle layer. Through key technology research and development, the dual-azimuth seismic acquisition was carried out by using single source and two streamers on both sides. We successfully implemented the experiment for the deep target seismic exploration in the South China Sea.%南海东沙海域的陆坡台地区, 浅表断裂及生物礁发育众多, 浅层新生界多为碳酸盐岩层, 中深层的中生界内部构造复杂, 断裂较多, 常规单船窄方位地震剖面显示中深层反射品质较差.利用双船可以设计灵活的观测系统, 形成双方位角地震探测方式, 对于地下同一反射点的照明, 可以获得比窄方位角探测更好的效果, 也可以改善高速屏蔽层下方、高陡倾角斜层等区域的成像质量.文章通过重点技术的攻关研发, 进行了单源激发、双缆接收的双方位角采集试验, 成功实现该方法在南海海域中深层地震勘探中的应用.