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

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.