川中中新元古代深层多次波压制技术研究

The Suppression of Meso-NeoProterozoic Deep Multiples in Central Sichuan

四川盆地中部中浅层存在多个强波阻抗界面,致使中新元古代深层发育大量强能量层间多次波,造成构造或地层假象,严重影响了该区深层的地质研究。由于层间多次波波场特征复杂,和一次波速度差异小,很难完全消除。经过噪声压制后,叠加剖面上仍然会有较强能量的多次波残留。针对川中地区此类叠加剖面上残留的强能量多次波,采用了F-X域最小平方滤波的方法,基于F-X域信号的可预测性进行多次波衰减。该方法在川中三维地震实际资料的应用中取得了良好效果,能够有效分离和压制强能量多次波干扰,深层资料信噪比得到了大幅度提高,基底反射特征符合区域地质认识。

Due to the existence of many strong impedance interfaces in the shallow formations,a lot of strong energetic interbed multiples are developed in the deep seismic data in central Sichuan basin,which result in structural or stratigraphic illusion and seriously influence the geological research on deep formation.The causes of multiples are complicated and the velocity difference between the primary wave and the multiples is small,so it is difficult to eliminate multiples completely.There are still many residual strong energy multiples on the stacked section after noise suppression.Against the residual strong energy multiples remaining on stacked sections,a method of least square filtering in F-X domain is proposed in this paper,which predicts and suppresses multiples based on the predictability of signal in F-X domain.The method has achieved good results in the application of 3D seismic data of central Sichuan.The result demonstrates that it can effectively separate and suppress strong energy multiples,the S/N of deep seismic has been greatly improved,and the base reflection features conform to the regional geological characteristics.