西湖凹陷黄岩构造三维地震采集参数设计与论证

EVALUATION AND DESIGN OF 3D SEISMIC SURVEY IN HUANGYAN STRUCTURE OF XIHU TROUGH IN EAST CHINA

地震勘探设计与评价 (SED)技术 ,是在对地质目标的理论分辨率计算和分析基础上 ,通过室内计算机模拟不同施工参数条件下的野外作业效果 ,最终实现地震采集参数的优化选择。在黄岩三维地震采集参数设计与论证中 ,针对二维资料频率偏低、分辨率不高、多次波发育等问题 ,对SED技术的应用条件进行了改进。①为控制多次波、提高信噪比 ,电缆长度由 30 0 0m增至 390 0m ;相应地 ,最小偏移距从 2 5 3m减小至 180m ,最大偏移距增大到 40 80m。②为保证所接收的地震信号频带宽而且高 ,电缆沉放深度由 11m减至 7m ,震源沉放深度从 7m减至 6m。③使用气泡比更大、频谱更宽、穿透力更强的SLEEVE枪阵。在实际作业中获得了高质量的三维地震资料 ,实现了真正意义上的“目标勘探”。

The seismic survey evaluation and design (SED) technology is realized on the basis of the theoretic resolution calculation and information analysis on the geological prospect. The computer simulation is used to achieve the best possible choice of the acquisition parameters. The existing 2D data from Huangyan structure show that the maximum frequency is limited in acquisition induced by the 11 m cable, so the appropriate shallower source and cable depth are recommended in 3D SED conclusions. A longer maximum offset of 3D than that of 2D survey is recommended in order to attenuate the multiple. Anyway the first use of SED in East China Sea has resulted in acquiring a high quality of 3D seismic data.