库车坳陷变质核杂岩与油气相态分布格局成因初探

塔里木盆地库车坳陷油气分布具有“西油东气”、天然气母质成熟度具有“北高南低”的特征。通过对库车坳陷变质核杂岩分布、烃源岩演化程度和地温梯度变化的分析认为：库车坳陷变质核杂岩的分布可能极大地影响了不同区带的地温梯度,从而影响了不同区带烃源岩的演化程度并控制了油气相态的横向变化。同时还认为变质核杂岩的形成时期还影响了库车坳陷侏罗系主力烃源岩同其他成藏要素的匹配关系。

PRELIMINARY DISCUSSION ON GEOLOGICAL DISTRIBUTION OF METAMORPHIC CORE COMPLEX AND HYDROCARBON IN KUCHE DEPRESSION

The distribution of oil and gas in the Kuche depression has a special feature,that is, "gas in the east,oil in the west" and the maturity of natural gas "higher maturation in the north,lower maturation in the south." The analysis of the distribution of the metamorphic core complex,the evolutionary degree of the source rock and the difference of geothermal gradient in the Kuche depression reveals the appearance of the metamorphic core complex may be the immediate cause.It is the existence of the metamorphic core complex that causes the different degree evolution of the hydrocarbon source rock in different areas and also controls the lateral changes of the hydrocarbon phases.The matching connection between the effective hydrocarbon source rock in Jurassic and the other factors of formating-resource in Kuche is also influenced by the time of formation of the metamorphic core complex.