Reconstruction of the tectonic evolution of the north Song Hong Basin offshore area in Vietnam based on seismic interpretation

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.