潜江凹陷GH地区盐岩强反射屏蔽下砂体识别方法研究  

Research on sand body identification method under strong reflection shielding of salt rock in GH area of Qianjiang Depression

作　　者：张水山[1] 李铭华[1] 罗兵[1] 张道洪[1] 易小芹[1] 张磊[1] 李琼[2] 岳林 ZHANG Shuishan;LI Minghua;LUO Bing;ZHANG Daohong;YI Xiaoqin;ZHANG Lei;LI Qiong;YUE Lin(Exploration and Development Research Institute of Sinopec,Jianghan Oilfield Company,Wuhan 430223,China;College of Geophysics,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中国石化江汉油田分公司勘探开发研究院,武汉430223 [2]成都理工大学地球物理学院,成都610059

出　　处：《成都理工大学学报（自然科学版）》2023年第6期756-766,共11页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：中石化股份公司科研项目(P22145)。

摘　　要：潜江凹陷潜江组地层是江汉盆地最重要的富烃凹陷和层组,其中GH地区位于潜江凹陷中北部,剩余油气资源十分丰富,具有较大的勘探潜力。然而该地区潜江组储层有效信号受盐岩强屏蔽影响,给砂体预测和岩性圈闭识别带来了极大困难。针对这一难题,本文开展了盐岩强反射剥离方法研究。在基于Ricker子波字典的正交匹配追踪地震信号重构基础上,分析了构建冗余字典的参数对匹配速度和精度的影响。通过构建双精度降采样字典进行匹配,提高了匹配速度和精度,获得比较准确的强反射时移、频率、相位信息,并在重构时恢复原子采样点,保证重构保真性,减小处理假象,最终形成了基于双精度降采样字典的分步正交匹配追踪强反射快速剥离改进算法(Stepwise Orthogonal Matching Pursuit of Double Precision Downsampling Dictionary),本文称之为DPDD-SOMP算法。运用该算法成功去除了该区产油层Eq 341顶部强反射。处理结果表明,DPDD-SOMP使盐岩强反射对下伏地层岩性的屏蔽效应得到有效削弱,被屏蔽的砂体在地震剖面上得以显现,为后续地震砂体预测与含油气检测提供了前提条件,对盐岩强反射剥离处理后的地震数据进行砂体平面属性及流体检测,结果与井点对应良好。The Qianjiang Formation in the Qianjiang Depression is the most important hydrocarbon rich depression and filormation in the Jianghan Basin.The GH area is located in the central northern part of the Qianjiang Depression,and the remaining oil and gas resources are very abundant,which has important exploration significance.However,the effective signals of the Qianjiang Formation reservoirs in this area are affected by strong salt rock shielding,which poses great difficulties in predicting seismic sand bodies and identifying lithological traps.In response to this issue,this article conducted research on the method of salt rock strong reflection peeling.On the basis of orthogonal matching pursuit seismic signal reconstruction based on Ricker wavelet dictionary,the influence of parameters for building redundant dictionary on matching speed and accuracy is analyzed.By constructing a double precision downsampling dictionary for matching,the matching speed and accuracy are improved,and more accurate information of strong reflection time shift,frequency and phase is obtained.And restore atomic sampling points during reconstruction to ensure reconstruction fidelity and reduce processing artifacts.Finally,a stepwise orthogonal matching pursuit of double precision downsampling dictionary is proposed,which is called DPDD-SOMP algorithm in this thesis.By using this algorithm,the strong reflection at the top of Eq 341 reservoir in the area was successfully removed.The processing results show that the improved algorithm effectively weakens the shielding effect of strong reflection of salt rock on the underlying formation lithology,and the shielded sand body can be displayed on the seismic profile,providing a prerequisite for subsequent seismic sand body prediction and oil and gas detection.Finally,the processed data was subjected to sand body plane attribute detection and fluid detection,which corresponded well with the well points.

关 键 词：潜江凹陷 盐岩强反射 双精度降采样字典 强反射剥离 砂体识别 

分 类 号：P631.4[天文地球—地质矿产勘探] TE321[天文地球—地质学]