松辽盆地龙凤山气田致密砂岩含气性预测研究

松辽盆地龙凤山气田营城组发育河流相致密砂岩储层,主力气层营Ⅳ砂组具有孔渗低、单砂体薄(3～5m)、非均质性强、弹性参数差异小等特点,优质储层识别和预测难度大。基于研究区岩样测试和岩石物理分析,优选致密含气砂岩的敏感弹性参数组合;通过叠前道集振幅恢复处理和叠前地质统计反演获取高分辨率的敏感弹性参数体,并利用贝叶斯分类方法识别致密含气砂岩。识别结果与实钻井结果吻合度较高,提高了薄层致密含气砂岩的预测精度,为后期开发井位部署提供了有效的技术支撑。

The Yingcheng Formation of the Longfeng Mountain gas field in Songliao Basin,China,has a fluvial facies tight sandstone reservoir.However,it is difficult to predict the effective reservoir of the gas field,because its main gas formation,the Ying IV sandstone formation,has inferior reservoir properties,namely,low porosity and permeability,a thin single-body thickness of only 3~5〖KG*9〗m,strong heterogeneity,and a small elastic parameter difference.According to rock sample tests and rock physics analyses of nine cores from the research area,we optimally selected the elastic parameter combination of tight sandstone,and obtained the elastic parameters sensitive to gas sandstone by means of pre-stack gather optimal amplitude recovery processing and pre-stack geological statistical inversion.Then,we adopted the Bayesian classification method to predict tight gas sandstone.The predicted result was highly consistent with the field drilling data,which means its high accuracy of tight sandstone gas prediction.The proposed method could provide support for well deployment.