基于动态字典的峰谷分离去强反射屏蔽方法  

Peak-valley separation and strong reflection masking method based on dynamic dictionary

作　　者：梁圆 李胜军[2] 段成祥 贺东阳 LIANG Yuan;LI Shengjun;DUAN Chengxiang;HE Dongyang(Shandong Provincial Key Laboratory of Deep Oil&gas,China University of Petroleum(East China),Qingdao 266580,China;Northwest Branch of Petroleum E&P Institute,PetroChina,Lanzhou 730020,China)

机构地区：[1]山东省深层油气重点实验室,中国石油大学(华东),山东青岛266580 [2]中国石油勘探开发研究院西北分院,甘肃兰州730020

出　　处：《石油物探》2023年第4期679-685,共7页Geophysical Prospecting For Petroleum

基　　金：中石油勘探与生产公司重大科技项目(2022KT1503);青岛国家海洋实验室专项基金(2021QNLM020001)共同资助。

摘　　要：地震数据中常存在强反射背景,例如灰质成分或因泥岩脱水等作用形成的高速层反射、煤系地层反射等,这些强反射屏蔽了储层的有效反射信息,使目的层反射较弱,影响了储层预测效果。为消除地震反射强能量对目的层反射特征的影响,通常采用以雷克子波作为基本原子的匹配追踪方法,由于雷克子波存在旁瓣,在去强反射同相轴时会对旁轴产生干扰。为此,提出一种基于Gauss子波的匹配追踪强反射屏蔽分离方法。Gauss子波没有旁瓣,而且具有控制参数少、能量集中的优点,在去强反射的同时不会对旁轴产生影响。该方法首先将Gauss子波作为基本原子建立动态子波库,其次利用层位信息获得强反射同相轴波峰波谷位置,然后依次对强反射同相轴的波峰波谷分别进行分解重构。通过设置残差阈值控制迭代次数,且每次重构时去除与地震强反射分量最大相关的分量,以达到消减强反射屏蔽的目的。设计了一维和二维强反射屏蔽模型验证了方法的适用性,理论模型和实际数据应用结果表明该方法能有效消减强反射屏蔽,突出强反射周围的弱反射信息,且分解后残余能量较少,不会对旁轴产生影响。A strong reflection often exists in seismic data,such as high-velocity layer reflection formed by ash composition or mudstone dehydration and coal measure stratum reflection.These strong reflections shield the effective reflection information of the reservoir and weaken the reflection of the target layer,thereby affecting the reservoir prediction.To eliminate the influence of strong seismic reflection energy on the reflection characteristics of surrounding rocks,a matching pursuit method with the Ricker wavelet as the basis function is typically adopted.Because of the existence of side lobes in this wavelet,the side axis was disturbed during dereflection.Therefore,a strong shielding separation method based on Gaussian wavelet matching pursuit was proposed.As a side-lobe-free wavelet,the Gaussian wavelet has the advantages of fewer control parameters and concentrated energy and will not affect the paraxial while removing strong reflection.In this method,the Gaussian wavelet was used as the basic atom to establish a dynamic wavelet library,and the positions of the peak and trough of the strong reflection in-phase axis were obtained using the layer information.The peaks and troughs of the strong reflection in-phase axis were then decomposed and reconstructed,respectively.The number of iterations was controlled by setting the residual threshold,and the component most related to the strong seismic reflection component was removed during each reconstruction to reduce the strong reflection shield.One-dimensional and two-dimensional strong-reflection shielding models were designed to verify the adaptability of the method.The theoretical model and practical data application show that the method can effectively reduce strong reflection shielding,highlight the weak reflection information around the strong reflection,and exhibit less residual energy decomposition and does not affect the paraxial.

关 键 词：匹配追踪 动态字典 Gauss子波 峰谷分离 强反射同相轴 消除地震强反射能量 

分 类 号：P631[天文地球—地质矿产勘探]