Constraining self-sourcing stratigraphic plays in North Sumatra: Integration of basin-petroleum system and stratigraphic forward modeling

Abstract

Stratigraphic traps are typically identified and delineated using 3D seismic analysis or by integrating well data. These plays involve greater exploration uncertainty than conventional traps, especially in regions where multiple petroleum systems coexist. A notable example is the self-sourcing stratigraphic trap, where hydrocarbons migrate laterally within coeval rock formations. This challenge is particularly significant in frontier areas lacking 3D seismic data and with limited well data. Therefore, developing a reliable methodology is essential to accurately identify potential stratigraphic trap zones while effectively accounting for the complex interactions within petroleum systems.

This study integrates stratigraphic forward modeling (SFM) and basin and petroleum system modeling (BPSM) to better constrain self-sourcing stratigraphic traps. The North Sumatra Basin was selected as the study area because it features a complex petroleum system involving three source rocks and various trapping mechanisms, including stratigraphic traps from the Middle Miocene. The systematic approach demonstrated in this study involves four key stages: (1) assessing geochemical evidence, (2) using SFM to delineate trap zones, (3) simulating organic matter distribution, and (4) applying BPSM to evaluate source rock maturation and hydrocarbon expulsion. This systematic approach provides a cost-effective framework for early-stage hydrocarbon exploration, helping geoscientists de-risk prospects before committing to high-cost data acquisition like 3D seismic surveys. It is particularly suited for evaluating stratigraphic traps associated with self-sourcing plays and has potential applications in unconventional resource exploration, including shale gas. Regionally, this research provides the first geochemical evidence of oil mixing in the area and presents conclusive insights into the four active petroleum system plays, potentially redefining exploration strategies in the region.