| The Mesozoic-Cenozoic basins in East Asia generally have undergone
three evolutionary stages: rifting, depression and inversion. Inversion
structure is the most important trap for hydrocarbon accumulation in East Asia.
The Daqing Field in the Songliao Basin, the largest oilfield in China, the
Pinghu Field in the Xihu Depression, East China Sea Basin, and the Minas Field
in the Central Sumatra Basin, Indonesian, the largest oilfield in Southeast
Asia, are all characterized by inversion structure. The Central Sumatra Basin is
an ideal model for petroleum exploration in inverted basin. Most of the oil
accumulations in the basin are controlled by inversion tectonics. The largest
oil accumulations in the basin result from combination of Paleogene graben with
thick oil-prone lacustrine shales overlain by thick marine clastic reservoirs of
Miocene age, high basin heat flows, and inversion tectonics that formed traps
above or near the kitchen center of graben and prior to the main phase of
maturation and migration.