基于正演分析的高阻抗地层下多次波压制技术

随着勘探程度的不断提高，勘探目标向着浅、深方向发展是我国东部老油田发展方向之一。在泌阳凹陷深凹区由于存在横向展布比较稳定的白云岩沉积，不仅屏蔽了地震信号能量的有效下传，而且造成了多次波的发育，加之深层系地层经强烈压实作用后，砂泥岩的速度、密度接近，没有较强的波阻抗界面，致使深层系地震资料的信噪比极低，极大地影响了构造解释和储层预测。在基于模型的多次波渐近射线法正演模拟结果基础上，搞清多次波的运动学和动力学特征，为多次波压制方法的选择提供依据，并提出相关的配套处理手段，提高深凹区白云岩高阻抗层下深层地震反射质量的处理水平。通过剔除拟合法去除多次波和能量补偿等手段，提高了泌阳凹陷深层系地震资料的信噪比和分辨率，取得了很好的勘探效果。 

The Technique of Multiple Removal under High Impedance Layers Based on Forward Modeling

With the improvement of the exploration degree,exploration target of old oil fields towards the deep and shallow is one of the development directions in East China.Dolomite deposition of lateral stable spread not only shields the effective downwards propagation of the seismic signal,but also generates multiples in Biyang deep area.The speed and density of sand and shale are similar and the difference between their impedances is small in deep series of strata formation after intense compaction,so low SNR is caused,which affects the structure explanation and reservoir prediction.Based on forward modleling result of multiple asympatotic ray of model,the paper states the kinematic characteristics of multiples and provides bases for the choice of the methods of multiple suppression.The paper puts forwards a correlative processing method to improve the processing technology of the deep seismic reflecting quality at high impedance of dolomite in deep depression.Multiple removal and energy compensation by deletion fitting method are used in Biyang deep depression,which improves the SNR and resolution of the deep seismic processing data and gets a good exploration effect.