The main body of the South Asian region is the Indian Plate

which was a part of the East Gondwanaland during the Rift Period (4570-166Ma) and then drifted from south to north for a long distance after the Late Jurassic (166Ma).Since the Eocene (49Ma)

the Plate began subducting towards the Eurasian Plate

causing the Himalayas and India-Myanmar Mountains rapidly uplifting from the Early Miocene (16Ma) to the present and the formation of five tectonic units.The passive margin sedimentary in northern Indian Plate had been destroyed in the pre-Late Cretaceous

while the east

west and southern parts of the Plate were subjected only to minor elevation and denudation

therefore hydrocarbons there were better preserved.During the Rift Period

the interior of the Plate only experienced weak subsidence

and during the late Collision Period

hydrocarbon source rocks were immature.Hydrocarbons were mainly concentrated in the passive continental margin

the foreland basins

the fore/back arc basins and the aborted rift systems along the edge of the Indian Plate

with the Meso-Cenozoic sedimentary rocks as the main reservoirs.Typical hydrocarbon migration and accumulation patterns are thought to be the composite sandbody's pattern

fold-thrust pattern

the fault-depression pattern and the fault-lithological pattern.