叠前密度反演技术在沙南凹陷中深层储层预测中的应用

APPLICATION OF PRE-STACK DENSITY INVERSION TECHNOLOGY TO MIDDLE-DEEP RESERVOIR PREDICTION IN SHANAN DEPRESSION

沙南凹陷中深层优质储层预测一直是油气勘探的难点,其砂泥纵波阻抗叠置严重,常规叠后反演手段无法准确有效预测储层,为此提出叠前弹性反演技术思路:通过岩石物理研究,开展砂泥岩弹性参数分析;采取对叠前CRP道集进行预处理,利用处理后的叠前CRP道集对岩性敏感的弹性参数进行反演试验,从多方面对反演方法和反演结果的可行性、可靠性进行分析;最终用沉积相研究成果,进行相控下叠前弹性反演,预测储层空间展布。该技术储层预测结果与已钻井揭示的情况吻合,横向变化及空间展布符合区域地质认识,能够较真实和详细地反映中深层储盖层空间变化特征,为后续钻井提供了重要的参考依据,具有广阔的应用前景。

To identify the distribution pattern of high-quality reservoirs in the middle and deep layers of the Shanan Depression is a difficult job in oil and gas exploration,where the sand and mud P-wave impedances are seriously superposed.Conventional post-stack inversion methods cannot accurately and effectively predict reservoirs.For this reason,a pre-stack elastic inversion technique is proposed.It includes:to carry out elastic parameter analysis for the sandstone and mudstone through petrophysical research;to pre-process the pre-stack CRP gathers,and use them to perform inversion tests on the elastic parameters sensitive to lithology;upon the basis,the feasibility and reliability of inversion methods and inversion results are analyzed;and finally,the results of sedimentary facies research are used to perform facies-controlled pre-stack elastic inversion to predict the spatial distribution of reservoirs.The reservoir prediction result of this technology is consistent with the situation revealed by drilling wells.The lateral change and spatial distribution conform to the regional geological framework,which can reflect the characteristics of the mid-deep reservoir caprock and its spatial change more truly and in detail,and provide an important reference to subsequent drilling.