柴北缘马海地区油气全烃地球化学特征与成因

通过对天然气组成、油气碳同位素、原油轻烃、中分子量烃和生物标志化合物等的研究,阐明了柴北缘马海地区油气的全烃地球化学特征,区分了不同油气的成因类型和可能来源。指出南八仙油气田和马海气田天然气为同一成因类型,南八仙油气田天然气属于高-过成熟煤成气,与伊北凹陷下侏罗统煤系烃源岩有关,而马北构造主要为高成熟早期腐殖型有机质成因为主的湿气,与尕丘凹陷和尕西次凹侏罗系腐殖型烃源岩有关;南八仙油气田原油主要属于煤成油,马北构造油则主要属于混合偏腐泥型成因油。

ORIGIN AND WHOLE-HYDROCARBON GEOCHEMICAL CHARACTISTICS OF OIL AND GAS FROM MAHAI AREA,NORTH EDGE OF QAIDAM BASIN

The paper adopts some methods such as gas composition, light hydrocarbon,carbon isotope, middle-molecular hydrocarbon and biomarker to illustrate whole-hydrocarbon geochemical charactistics of oil and gas from Mahai area and identify the genetic type and source of the different genetic oil. The result shows that gas from Nanbaxian and Mabei oil-gas field is the same genetic type, But the gas of Nanbaxian field is mainly high-over mature coal formed gas ,which is associated with lower Jurassic coal source rock in Yibei depression. Natural gas from Mabei structure is mainly wet gas of high mature early period, which is associate with Jurassic humic source rock in Gaqiu depression and Gaxi hypo-depression. Crude oil is mainly coal formed oil in Nanbaxian field, while crude oil is mainly sapropel-type oil in Mabei structure.