ABSTRACT: Sequence stratigraphic study and detail sedimentological analysis to efficiently drain multitude deltaic reservoirs: A Case study in Miocene distributary mouth, Kutai Basin, Indonesia

Setiawan, Aris, H. C Baskara, and F. H Sidi , VICO Indonesia, Jakarta, Indonesia

Integration of sequence stratigraphic correlation, reservoir mapping and in-depth depositional environment analysis have successfully defined proper reservoir geometry, distribution and heterogeneity in the Middle Miocene prolific zones of Nilam field, Kutai Basin. The case example is a complex reservoir consisting of three successions of high permeability but thin sandstones with thickness less than 20 feet deposited in a predominantly delta front environment. This study is a part of a major re-evaluation project on onshore fields of Kutai basin. A closer look at some distal deltaic reservoirs has greatly improved the understanding of interaction between sediment influx and relative sea level fluctuations. The gross succession the example initiated by coarsening upward successions from low resistivity shales at the base of the parasequence. The lower reservoir shows the initial development of distributary mouth bar system with minimal sand accumulation, followed by the middle reservoir acting as the optimum phase of the system. The final succession of this complex reservoir is a distributary channel fill, with at least three individual channels. This reservoir complex then capped with laterally extensive distribution of coal, showing the development of interdistributary area. Despite its continuous and laterally extensive distribution, each reservoir unit has several very thin sandstones layers that interestingly may act as an efficient permeability barrier to lateral fluid flow. Differential depletion demonstrates the compartmentalization within this reservoir complex.

AAPG Search and Discovery Article #90913©2000 AAPG International Conference and Exhibition, Bali, Indonesia