Abstract:

Manite depression is one of the largest depressions in Eren Basin.It covers an area of more than 10,000km²,trending NE.It is a Meso-Cenozoic depression developed on a folded and metamorphic Paleozoic basement,and under wenta long process of tensive faulting-block faulting-subsidence-degeneration.Sedimentary formation is mainly composed of Jurassic-Cretaceous rocks with athickness of over 6,000m.The varied sedimentary facies,controlled by the majoractive fault at the margin of the basin,includes diluvial deposites,alluvial fan,fluvial sand,valley flat and lacustrine sediments.The facies zone change intensively and the thickness of each is unstable.But along the fault in the center of the depression,some synchronous depressions developed there.These depressions keep their own inherent properties,distribute in series with thicker sourcerocks and abundant organic matters,favourable for hydrocarbon generation.Inside the depression,there are two petroleum generation segs with one upliftin between,i.e.Aershan fault belt which possesses good reservoir and caprocks and different types of traps.In the early stage of exploration,commercialoil and gas flows were obtained from five traps of the fault belt.It is thus proved to be the best hydrocarbon enrichment zone of Manite depression.