多尺度四阶累积量相关分析方法及其应用

Predicting sand bodies with correlation analysis of multi-scale 4th order cumulant.

中国石油大学(华东)地球资源与信息学院, 山东东营257061

Earth Resource and Information Institute,University of Petroleum,Dongying 257061,China

胜利油田正里庄地区沙三中段重力流成因的湖底浊积扇砂体厚度薄,与围岩物性差异小,地震反射信号较弱,在地震剖面上难以识别。为此,提出了地震信号多尺度四阶累积量相关分析方法。方法的基本原理是：首先对地震记录进行多尺度小波分解；然后将分解后的各尺度信号进行四阶累积量计算,并对每一尺度四阶累积量进行相关滤波；最后将各尺度四阶累积量相关滤波的结果进行组合,重构地震信号。该方法可以对地震信号中的噪声,尤其是非高斯性噪声进行一定程度的压制,突出湖底浊积扇砂体的地震响应。正里庄地区的高898井在沙三中段钻遇多个砂体,有2个厚度在4m左右的砂体在原始地震记录上反射信息很弱,不易识别,经多尺度四阶累积量相关分析方法处理后,砂体的地震反射信息得到了加强,在地震记录上清晰可辨。

The turbidite fan sand body formed by density current in Es3 in ghenglizhuang area,Shengli oilfield is thin in thickness and is difficult to identify on seismic sections because of small difference in physical property between the sand body and surrounding rocks and faint seismic reflection.So the multi-scale 4th order cumulant cor-relation analysis method is proposed to deal with the seismic sig-nals.The basic principles of the method are 1) decomposing seis-mic signals with multi-scale wavelet first.2) calculating each-angle decomposed signal by 4th order cumulant and filtering them,3) composing the relative filtering result,and 4) rebuilding the seis-mic signals.The method can suppress noises to a certain degree, with the none-Gauss noise in particular,so that the response char-acteristics of the turhidite fan sand body can become much clearer. Well Gao898 in Zhenglizhuang area was drilled through many sand bodies and two of them with 4m in thickness were found very weak in reflection signal on the original seismic record and so were diffi-cult to recognize.After being processed by the multi-scale 4th or-der cumulant correlation analysis,the seismic reflection informa-tion of the two sand bodies are strengthened and become easy to recognize.