Sedimentary facies, depositional environment and reservoir quality of Group-B shallow clastic reservoir in the Malay Basin, Malaysia

Abstract

Shallow reservoirs in Group-B of MS-field in Malay Basin, Terengganu's offshore, Malaysia were explored for development. Poor understanding of depositional settings, stratigraphic context, lithofacies, reservoir geometry, reservoir quality, and heterogeneity are some of the difficulties encountered in developing these shallow reservoirs. In this study, these challenges were circumvented by performing reservoir architecture and quality analysis. This was achieved by integrating the interpretation from the cores, well logs, petrographic and petrophysical analyses for depositional model generation, lithofacies description, as well as reservoir geometry, continuity, and quality determination. Five lithofacies were identified in Group- B, namely: laminated mudstone (ML), bioturbated mudstone (MB), heterolithic mud dominated (MH), heterolithic sand dominated (SH), and bioturbated sandstone (SB). The sediments encountered in ML and SB lithofacies consist of moderate to good reservoir quality, while for SH and MH, they ranged from high to low quality. This study provides a better insight to the shallow reservoir heterogeneity in MS-field and the results obtained could also be applied to the other similar shallow reservoirs for characterization and modelling improvement processes.