分频AVO技术在安岳气田须二段储层含气性分析中的应用  

Application of frequency division AVO in the gas-bearing analysis of reservoir in the Xu-2 Member of the Anyue gas field

作　　者：宋晨 金吉能[1] 潘仁芳[1] 朱博远 喻志骅 唐小玲 SONG Chen;JIN Ji-Neng;PAN Ren-Fang;ZHU Bo-Yuan;YU Zhi-Hua;TANG Xiao-Ling(School of Earth Sciences,Yangtze University,Wuhan 430100,China;Research Institute of Petroleum Exploration and Development,Beijing 100007,China;Exploration and Development Research Institute of Huabei Oilfield,Renqiu 062552,China)

机构地区：[1]长江大学地球科学学院,湖北武汉430100 [2]中国石油勘探开发研究院,北京100007 [3]华北油田勘探开发研究院,河北任丘062552

出　　处：《物探与化探》2023年第3期681-689,共9页Geophysical and Geochemical Exploration

基　　金：国家科技重大专项课题“致密气有效储层预测技术”(2016ZX05047-002)。

摘　　要：四川盆地安岳气田须二段致密气储量丰富,地质特征相对复杂,常规AVO分析方法预测储层含气性分布的精度较低,需要研究采用更加精细的地震预测方法。基于单井岩石物理和正演模型特征分析,采用基于小波变换下的分频AVO反演,优选出优势频段的AVO属性进行融合构建含气性因子,进而对安岳气田须二段有利含气富集区带进行分布预测。结果表明,须二段气层主要表现为Ⅳ类AVO响应异常。优势频段35~45 Hz的气、水层AVO响应比全频段的AVO响应的差异特征较明显,差异性更大,更易突出含气响应特征;AVO含气性敏感属性为相对横波速度差异、相对泊松比差和流体因子,经融合得到含气指示因子的负异常区域指示含气有利区;井震对比可知优势频段AVO属性的含气性预测效果较好。该方法以期为非常规油气勘探提供技术支撑。The second member of the Xujiahe Formation(the Xu-2 Member)in the Anyue area of the Sichuan Basin enjoys abundant tight gas reserves.However,this member has complex geological characteristics,and conventional amplitude versus offset(AVO)analysis has relatively low precision in predicting the gas-bearing property of the reservoir in this member.Therefore,it is necessary to develop a more fine-scale seismic prediction method.Based on the analysis of single-well petrophysical characteristics and forward models,the AVO attributes of the dominant frequency range were selected through the frequency division AVO inversion based on wavelet transform.Then,these AVO attributes were fused to form the gas-bearing indicator,using which the distribution of favorable gas-enrichment zones in the Xu-2 Member of the Anyue area was predicted.The results are as follows:The gas zones in the Xu-2 Member primarily present class IV AVO anomalies;For the gas and water zones,their AVO responses in the dominant frequency range(35~45 Hz)differed significantly from those in the full frequency band,and their gas-bearing response characteristics were more pronounced in the dominant frequency range;The AVO attributes sensitive to the gas-bearing property included the difference in the S-wave velocity,the difference in Poisson's ratio,and the fluid factor.The gas-bearing indicator was obtained through the fusion of these AVO attributes,and the negative anomalies of the gas-bearing indicator were indicative of favorable gas-bearing zones;The seismic-log correlation shows that the AVO attributes in the dominant frequency range yielded positive gas-bearing prediction effects.The method proposed in this study is expected to provide technical support for unconventional oil and gas exploration.

关 键 词：分频AVO 小波变换 优势频率 致密气砂岩 储层预测 

分 类 号：P631.4[天文地球—地质矿产勘探]