琼东南深水坡折带地震采集炮检距特征分析

中国南海北部琼东南盆地油气资源丰富,勘探前景光明。但该区广泛分布的深水坡折带和崎岖海底导致其地震资料信噪比低,侧面波发育,深部构造成像质量差。本文根据琼东南盆地深水陆坡区典型的地质剖面建立正演模型,采用高斯射线束照明模拟法分析、对比深部凹陷及复杂构造目的层不同炮检距的照明能量分布特征,得知对深部目的层成像最有效的排列长度是7000~9000m、最优叠加炮检距范围是4000~5000m。这对海上深水陆坡区地震勘探数据采集观测系统的优化设计具有重要意义。

Seismic acquisition offsets in deepwater slope area,Qiongdongnan Basin

The Qiongdongnan Basin in the northern South China Sea is rich in oil and gas resource with huge exploration potential.But slope breaks in deepwater continental slope area make poor seismic imaging quality of deep structures due to its low S/N data and serious lateral interference.A forward model was built on the representative geological profile in the deepwater slope area of the basin.Based on Gaussian beam illumination modeling, the illumination energy distributions,which are obtainecl with different offsets from deep sag and complex structure targets,were analysised.The results reported here suggests that the most effective offset range is from 7000to 9000mand the optimum stacking segment is from 4000to 5000mfor deep target imaging. This observation can provide guidance for optimized seismic acquisition design in the area.