Minas North West Segment (NWS), such as Minas field, has been known as a complex fluvial deltaic system which has had sand and shale heterogeneity both in lateral and vertical distribution. As a mature field, Minas NWS need more effort in order to optimize and to preserve current oil production. The geological model need to be updated for better reservoir optimization process, unfortunately interpretation from the normal amplitude seismic section failed to delineate more detail reservoir distribution and made difficulty in well logs correlation because of reservoir complexity. Multiattribute seismic analysis has been selected as a method to help made better interpretation and delineated reservoir distribution and well logs correlation. Multiattribute seismic analysis predicts reservoir properties or log properties from several seismic attributes. The prediction was done by finding a relationship between well log data and seismic attributes at well location. Once the best correlation was found, it can be applied to 3D seismic section and generated 3D pseudo log properties. In Minas NWS, we divided analysis into two (2) intervals because of difference reservoir’s characteristic. We succeed to generate several pseudo reservoir/log properties from Multiattribute seismic analysis, e.g.: gamma ray cube, density cube, p-wave cube. The analysis results have been checked by doing cross validation and blind validation which showed us that the results can be accepted, we have had good match between predicted/pseudo log and actual log with average correlation coefficient value more than 70 percent (0.7). Finally, using pseudo log cubes or its combination, reservoir distribution can be interpreted better and more detail than if we only used conventional seismic section that have been done before. The pseudo log properties give us more detail information about reservoir characteristic itself, not only contrast impedance or layer boundary (reflection coefficient).
Authors : Wahyu Setiawan, Tafsillison & Hendarmin