Characteristics and genesis of the Ordovician crude oil in the RePu area, Halahatang sag, Tarim Basin, China

摘要

The RePu area is located in the Tarim Basin, China. Based on the exploration and development, this paper analyzed the characteristics of the Ordovician crude oil and the source rocks by gas chromatography-mass spectrometry. The Ordovician carbonatite reservoir oil in this area exhibited light component, rich chain hydrocarbon and poor aromatic hydrocarbon. The composition of C7 compound showed the advantage of n-heptane, which belonged to type I generative kerogen, and it was deep buried highly mature crude oil. The crude oil biomarker compounds all exhibited high content of long-chain tricyclic terpanes and high Ts/Tm values. The large presence of alkane aromatization compounds indicated strong reducing environmental conditions during crude oil formation. By comprehensive judgment that the main oil source of the Ordovician reservoirs in the RePu area was the Cambrian source rock.