Geochemistry, origin and distribution of natural gases in Tarim Basin, NW China

Abstract

The natural gases in Tarim Basin are mainly distributed in the foreland and platform areas. They are coal-formed and oil type and the proved natural gases are mainly coal-formed. Over 83% of the proved gases in Tarim Basin lies in the Central-Asia coal-formed gas accumulation domain. All the gas pools are distributed along the fractured belts. The fractures are generated by tectonic movements, and they serve as pathways for the gas migration. The tectonic-generated fault interrelated drapes provide excellent traps for the gas accumulation. The gas reservoirs experienced multi-period gas accumulation, but the late gas accumulation was much important for the gas pool formation. The latest gas accumulation happened during the late Weixishan period. Compared with the Jurassic coal measures in the east Tarim Basin, the coal measures in Kuche Depression has a higher gas generation rate, which is favorable for the large-middle-sized gas reservoir formation.