Normal faulting and role of the reverse drag in analyzing petroleum systems, an example of 2D modeling from the Nam Con Son Basin (Vietnam)

Abstract

AbstractThe studied area is located around a margin of the Nam Con Son Basin (NCSB) (Vietnam). A 2D seismic interpretation data indicated two main structural domains that could influence the hydrocarbon distribution – hanging wall and footwall of the possible large-scale reverse drag. In this study by using Cenozoic petroleum systems modeling around a cluster of normal faults we investigate present day migration paths assessing the role of hanging wall and footwall domains in hydrocarbon exploration. In order to analyze fluid migration, we reconstructed burial history, timing of hydrocarbon generation, migration paths with emphasis on tectonic model further observing the present day hydrocarbon distribution. The complete results of the petroleum system modeling are presented by Spahić et al. (in press) whereby in this paper, we focus on the footwall domain of the main normal fault.The studied section exhibited finite length faults that are associated with possibly two rifting phases, whereby the role of Master faults was separate to investigate fluid distribution. Faults are root in the basement propagating towards the higher sections. For the modeling, Paleogene Formations accommodated in near-shore and lacustrine environment are adopted as potentially the main source of the fluids. The higher sections are divided into the reservoir and trap systems and are tested for fluid migration using PetroMod 2012.2 (Mark of Schlumberger). Results indicate that main migrations routes could be associated with the main fault further distributing fluid across the investigated section. The two main structural domains, large-scale hanging wall and footwall most probably associated with the reverse drag developed around the main normal fault could be treated as a potential trapping mechanism. The computed migration paths pointed that not only well-known rollover anticlines could be recognized as a potential trap system, but also perspectives of the footwall domain could be further investigated.