142 / 2014-09-06 16:28:40

The Structural Features, Prototype-basin Reconstruction And Petroleum Exploration Potential Of The Bay Of Bengal Basin

5047,5048,5049,5050,5051

Based on the satellite-derived gravity data processed by applying various image enhancement methods (filter, gradient and continuation) and the cross sections of standardized seismic reflection profiling, the tectonic features and dynamics of the Bay of Bengal Basin are presented. Free-air gravity anomalies and their results of enhanced processing indicate that there are NW-trending fracture zones in the west, EW-trending faults in the Ninetyeast Ridge, and NE-trending linear structures in the east of the basin, which suggest the influence of sea floor spreading, ridge emplacement and Indian Ocean crust subduction, respectively. Based on the standardized seismic reflection profiling, gravity anomalies and stratum thickness, the basin comprise five tectonic/stratigraphic units, and can be divided into five structural elements that are West Depression, 85°E Ridge, Central Depression, Ninetyeast Ridge and Rakhine Depression. Prior to the collision, the sedimentary framework was controlled by multiple isolated rises developed in 85°E Ridge, which was the response of episodic eruption processes of the hotspot. Whereas, the post collisional sediments known as the Bengal fan sediments were not prominently affected by the ridge and the sediments continuous migrated southward during the Eocene to Miocene. The subduction of the Ninetyeast Ridge promoted the westward growth of Andaman Accretionary in the south (7°N～14°N) and controlled the evolution of Rakhine Depression, Indo-Burmese Wedge and the depocenter of the Bay of Bengal Basin in the north (14°N～20°N). We restored the protooceanic basin stage (Later Cretaceous to Early Oligocene) and the remnant ocean basin stage (Later Oligocene to present) of the Bay of Bengal basin based on detailed marine geophysical investigation and geological evidences analysis since Late Mesozoic. The two main prototype-basins contain different geophysical characteristics, structures features and tectonic evolution process, which result in variation in source rock, traps, hydrocarbon accumulation process and modes. We proposed that source rock and traps might have a good relationship in time and space. It can be summarized the relationship of tectonic and reservoiring evolution that tectonic evolution controlled the proto-type basins/structural units, which controlled the source rocks and traps, and these most important elements controlled reservoiring evolution of the Bay of Bengal Basin.