Abstract

The Phu Khan Basin and Hai Phong Sub-bain are two underexplored basins offshore Vietnam. Both basins are characterised by initial extension tectonics but have contrasting post syn-rift evolution. The Phu Khan Basin shows no evidence for a through-going wrench fault system. A mild compressional event during the Middle Miocene caused re-activation along pre-existing extensional fault. Compression event appears to have ceased by the end of the Middle Miocene. There is no evidence for late wrench induced structures. Post Middle Miocene the basin transformed into a passive margin with the deposition of progradational and aggradational mega-sequences. Late hydrocarbon generation and expulsion provides favorable timing for trap formation and hydrocarbon charge. The Hai Phong Sub-basin is a deep basin with rapid burial and an early phase of generation and expulsion pre-dating trap formation. It is a major Middle Miocene inversion with uniform subsidence post Middle Miocene event with continuing hydrocarbon generation. Late Pliocene to recent inversion also occurred. The late hydrocarbon expulsion phase provides favorable timing for gas charge to late formed inversion structures and oil and gas to buried hill traps.

Keywords: Block 101-100/04 • Block 123 • Block 12W • Dam Thi Nai Oil Seeps • Tectonostratigraphy

Presented at: 2009 South East Asia Petroleum Exploration Society (SEAPEX) Conference, Singapore, 2009