基于结构中值滤波的CRP道集优化处理技术  

Optimization technology based on structure median filter for CRP gathers

作　　者：许璐[1] 刘志成[1] 王小青[1] 谢金娥[1] 贾春梅[1] 

机构地区：[1]中国石油化工股份有限公司石油物探技术研究院,南京211103

出　　处：《地球物理学进展》2015年第4期1804-1810,共7页Progress in Geophysics

摘　　要：共反射点道集中的噪声与剩余时差影响着偏移剖面的质量和叠前反演的精度.本文采用二次多项式拟合地震数据对地层倾向进行估计,并基于结构中值滤波方法对共反射点道集进行优化处理.在计算时窗内,对道集中每一个样点的二次多项式拟合系数进行精确扫描以确定样点所在同相轴方向并在同相轴方向进行中值滤波即结构中值滤波,滤波后道集信噪比得到提高同时保护了地层边缘特征.由于相关性在叠加剖面中要优于存在剩余时差的道集间,因此本文在叠加剖面上通过建立模型道来进行剩余时差校正即通过计算滑动时窗内待校正地震道和模型地震道间的互相关值,以最优化原则逐道估计剩余校正量,得到每个共反射点道集的剩余校正量模型,然后对剩余校正量模型在空间上做平滑处理,最后对共反射点道集进行时差校正.理论模型数据和实际数据的处理结果表明,该方法能够很好地解决道集中的信噪比和剩余时差问题,提高了共反射点道集和叠加剖面的整体质量.Noise and residual moveout in CRP gathers affect the quality of migration profile and prestack inversion.In order to improve the quality of CRP gathers,We tried to use quadratic polynomial to fit the seismic data,which provides dips of seismic events,and combine with the structure median filter.The events in the gather have good correlation characteristics,So the polynomial coefficient can be got by scanning inside the running window for a local dip,then follows the dip orientation as a pilot,calculating the correlation factor.The SNR have been improved after structure median filter,while preserving seismic edges and details such as faults and fractures.Because of the correlation in seismic profile is better than gathers,the model trace is builded at the stacked section,then the algorithm estimates the time shift by calculating the cross-correlation of the input data with a model trace.The conditioning processes for CRP gathers can be corrected by the model of residual moveout after smoothing.The proposed method has been applied to both the synthetic and real data,The processing results show that the method can effectively improve the SNR and correct theresidual moveout in gathers.

关 键 词：CRP道集 倾向估计 中值滤波 噪声衰减 剩余时差 

分 类 号：P631[天文地球—地质矿产勘探]