波动方程叠前τ偏移技术在永安三维地震资料处理中的应用

Application of wave equation prestack τ migration on Yongan 3D seismic data of Northern Jiangsu Basin

(1.中国石油化工股份有限公司江苏油田分公司物探技术研究院,江苏南京210046;2.同济大学海洋与地球科学学院,上海200092)

Geophysical Prospecting Technology Research Institute,Jiangsu Oilfield Subsidiary Company，SINOPEC,Nanjing 210046,China

永安三维工区地下地质结构复杂,火成岩广泛发育,严重影响了该地区的地震成像效果,主要表现为小断层成像质量差、火成岩附近反射界面能量弱、目的层难以追踪解释。经过多轮叠前时间偏移处理仍然未取得满意的成像结果。为此,引入了双平方根(DSR)单程波动方程叠前τ偏移方法。该方法要求输入的地震数据为零方位,因此需要进行方位时差校正和炮检距规则化。针对窄方位三维地震数据特点,提出了DMO校正+炮检距面元化+DMO-1校正流程。分别利用Kircohoff叠前偏移和叠前τ偏移＋DMO校正+炮检距面元化+DMO-1校正方法对永安三维地震资料进行处理,结果表明,后者的应用效果较好,火成岩之间反射层位同相轴连续性得到改善,断层断面更清晰,成像分辨率明显提高，而且两者耗时几乎一样,证实了DSR单程波动方程叠前τ偏移方法的实用性。

Yongan 3D area has complex subsurface geologic structure,and igneous rock is widely developed,which seriously impacts the seismic imaging of the area,displaying as bad imaging of small fault,weak energy of reflection interface near to igneous rock,and difficult to trace and interpret target formation.After several times of prestack time migration,good result still cannot be achieved.Therefore,double-square-root (DSR) one-way wave equation prestack τ migration was introduced.The method requires zero-azimuth seismic data,so azimuth moveout correction and offset regularization is need.Aiming at the characteristics of narrow-azimuth 3Dseismic data in the area,we proposed a workflow including DMO correction,offset regularization and DMO-1 correction.Both Kircohoff prestack migration and the prestack τ migration combined with above workflow were applied to Yongan 3D data.Result shows that the latter method can improve the continuity of reflection events between igneous rocks,make the fault and fault section clearer,and increase imaging resolution.Meanwhile,the two methods cost almost the same time,which proved the feasibility of the latter method proposed here.