Geodynamic
Evolution and Its Significance upon Hydrocarbon Systems in Tarim Basin, China
He, Dengfa1,
Chengzao Jia2, Xinyuan
Zhou3, Chaojun Zhang1, Xuejun Pi3 (1) Research Institute of Petroleum Explorarion and Development, Beijing, China (2) PetroChina Ltd, China (3) Tarim
Oilfield Company, PetroChina Limited Company
The Tarim Basin
is a large composite and superimposed sedimentary basin developed upon pre-Sinian continental basement. It has undergone three
mega-cycles of extension and compression. During Sinian
to Middle Devonian, which is called a period of paleo-Asian
or proto-Tethyan, it had developed as a continental
rift and then to passive margin and to foreland basin at the end. During Late
Devonian to Triassic, a period of paleo-Tethyan, it
had been a continental rift and then passive margin at the beginning, and
evolved into a retroarc extensional basin and
finally become a retro-arc foreland basin in its southwestern margin. During
Jurassic to Quaternary, a period of neo-Tethyan, it
had started as a continental rift or depression, followed by intervening local
or regional compression, and at last evolved into a large composite foreland
basin. The long and multiple periods of tectonic evolution has
resulted in the complex superimposition of proto-basins of variable types in different
periods, giving rise to a complicated geological framework.
The extensional
sequences is much more continuous, containing the three series of effective
source rocks such as Cambrian to Ordovician, Carboniferous to Permian, and
Lower to Middle Jurassic. The compression basins are characterized by rapid
changes in the depositional systems. Such compressions has formed lots of
structures ready for hydrocarbon trapping, and accordingly given rise to three
critical moments for oil and gas accumulation. The exploration up to now has
proved that the Tarim basin has been rich in oil and
gas, and has great potential for exploration.
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