复杂断块成像技术在泌阳凹陷地震勘探中的应用

Application of complex fault visualization on the seismic exploration of Qinyang depression

由于泌阳凹陷北部斜坡带断裂系统发育以及目的层段沉积存在较大差异,导致地震施工难度较大,地震资料的品质难以满足勘探开发的需要。因此,开展了以提高复杂断块清晰成像为目的的三维地震勘探方法研究。首先,通过改善激发条件解决了研究区地表疏松砂砾层导致的单炮强低频干扰问题;其次,利用以往资料对炮密度与地层成像的信噪比之间的关系进行了研究,优选了野外施工因素,解决了研究区核三段上、下亚段因沉积差异性导致的地震资料品质响应问题;最后,针对复杂断块群波场复杂引起的断层反射难以聚焦成像的问题,应用双聚焦成像等技术,对三维观测系统参数进行了优化设计。方法实施后取得了较好的效果,复杂断块的断层成像更加清晰,尤其是核三段下亚段地震资料的信噪比与分辨率有了明显提高,达到了预期的勘探效果。

The development of fault system of the north slope zone and the big depositional difference in Qinyang depression result in the big difficulties in the seismic acquisition and the poor data quality,which can not meet the requirement in the oil field exploration and development.To solve this problem,a 3D seismic acquisition method research,aiming at increasing the imaging result for complex fault block,was carried out.First,the serious low frequency interference in single shot record due to the loose sand layer in surface layer was solved by improving the shooting conditions;Second,the influence to the data quality from the depositional difference in upper H_3 and lower H_3 was solved by studying on the relation between source density and S/N ratio and better selecting the field operation parameters.Finally,to solve the difficulties in imaging the fault caused by the complicated wave field in complex faults layer,the double-focus imaging technology was applied through better selected geometry parameters and optimized technical design.By applying methods mentioned above,the anticipated exploration goal was reached and the complex fault can be clear imaged,especially the S/N ration and resolution in lower H_3 improved significantly.