Abstract:

The block-faulted zone in the northern margin of Qaidam Basin is a terrestrial sedimentary region of the Meso-Cenozoic with an area of 30000km².within the province,overthrust faults and folds are well developed with the sediments of the Triassic,Jurassic,Cretaceous,Tertiary and Quaternary.Among them,Jurassic sediments in the type of a piedmont depression,is a major hydrocarbon-producing formation with a thickness of 600m.Organic aboundance of which is high,and organic matters are mainly Ⅲ type which in some places have reached a mature stage.Carboniferous marine sediments of the basement may be a potential hydrocarbon-producing formation.It is believed that all conditions are available for the formation of hydrocarbon reservoirs in this region.Among four secondary tectonic units within the area,Saishiteng sag in the western depression is the most favourable for the prospect of oil and gas,and the central uplift and eastern sag,Ainan slop,on the other hand,is considered to be less favourable.