Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Huyen T. T. Bui ¹, Y. Yamada ², T. Matsuoka ²

Affiliations
1 Department of Geophysics, 397 Panama Hall, Stanford University, CA 94305, US
2 Department of Civil and Earth Resource Engineering, Graduate School of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501, JP

Abstract

The Song Hong (Red River) Basin is a typical pull-apart basin in Southeast Asia, located in northern Vietnam, extending from onshore to the offshore Gulf of Tonkin. It was formed by the Red River Fault displacement and South China Sea opening, and can be divided into three main parts due to stratigraphic distribution: onshore, northern offshore area and southern offshore area. This basin is considered to have a high potential for hydrocarbons, but only some gas fields have been found to date. In this study, we reinterpreted two-dimensional seismic data from the north Song Hong Basin to build structural maps of the study area. Reconstruction of the tectonic evolution of some typical sections illustrates the structural configuration and especially development of the fault system in the area. The newest results of re-interpretation reveal many flower structures and evidence for the right lateral displacement on the Red River fault after 5.5 Ma, unreported in previous works. This can be used to explain the complex structure of Song Hong Basin and suggests the reason why exploration for hydrocarbon traps is very difficult.

Keywords

Tectonic Evolution, Seismic Interpretation, Hydrocarbon Traps, Basement High, Flower Structures, Song Hong Basin, Vietnam.

Full Text

     

Huyen T. T. Bui ¹, Y. Yamada ¹, T. Matsuoka ¹

Affiliations
1 Department of Civil and Earth Resource Engineering, Graduate School of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto, 606-8501, JP

Abstract

Located in the eastern margin of South East Asia, Vietnam territory was strongly influenced by the India- Eurasian collision during the Cenozoic with two major regional tectonic events that are the displacements on the Red River Fault and the opening of the South China Sea. The Cuulong Basin experienced the tectonic activities caused by the South China Sea spreading. Block 15-2 in the Cuulong basin south of Vietnam is a Well-Known area with some oil fields comprising High-Yield zones located in a fractured granite basement. The Vung Dong prospect in this block includes a basement high with extensive faulting. This present work is on the seismic interpretation of the 3-D seismics in an area of 6 x 12.5 km². From interpretation of Three-Dimensional seismic data for this prospect, two major fault systems are identified; an older fault system of Eocene-Oligocene in age affecting basement, and a younger fault system active during the Miocene time, that is correlated with the opening of the South China Sea. Activation of the younger faults in this area resulted in basement uplift and truncation of Oligocene sediments at the basement high, where younger Miocene sediments directly overlie the basement. A 3D structure model is constructed for this prospect based on this seismic interpretation, providing an overview of the structure and tectonics to aid the assessment of oil and gas accumulation potential of the region.

Keywords

3D-Seismics, Basement Cover Structures, Cuulong Basin, Vung Dong Hydrocarbon Prospect, Offshore Vietnam.

Full Text