准噶尔盆地石炭系烃源岩发育模式及地球化学特征

石炭系是准噶尔盆地油气勘探的重要层系,油气成藏具有明显的源控特征.查明石炭系烃源岩地球化学特征,对于精细厘定有效烃源岩,指导油气勘探具有重要的现实意义.系统采集露头和钻井烃源岩样品,采用总有机碳含量、岩石热解、饱和烃色谱-质谱、单体烃碳同位素和金管-高压釜生烃热模拟实验等分析手段,对烃源岩地球化学特征及生烃能力开展对比研究.结果表明:准噶尔盆地石炭纪残留洋(海)、弧后盆地、弧内盆地、海相裂谷环境和陆相裂谷盆地等沉积环境形成了5种烃源岩发育模式;不同环境的烃源岩表现出不同的地球化学特征,可分为5种类型,分别为乌参1井型烃源岩、滴水泉型烃源岩、扎河坝型烃源岩、滴西8井型烃源岩和五彩城型烃源岩;不同环境发育的烃源岩的生烃能力存在明显差异,其中,弧后盆地和弧内盆地烃源岩表现为强生烃能力,为优质烃源岩,其生成的油气是油气勘探的重要目标.

Development mode and geochemical characteristics of Carboniferous source rocks in Junggar Basin

The Carboniferous strata is important for hydrocarbon exploration in Junggar Basin,and its hydrocarbon accumu?lation is mainly controlled by source rocks.Identifying geochemical characteristics of the Carboniferous source rocks is sig?nificant to determine the effective source rocks in detail and to guide hydrocarbon exploration.The outcrop and drilling samples of source rock were systematically collected and the analysis methods were used including organic carbon content,rock pyrolysis,chromatography-mass spectrometry saturated hydrocarbon,single hydrocarbon carbon isotope,and experi?ment of hydrocarbon generation thermal simulation in gold tube-autoclave to study the geochemical characteristics and hy?drocarbon generation capacity of source rocks.The results show that there are five types of source rock development modes of the Carboniferous strata in Junggar basin resulted from five types of sedimentary settings,namely residual ocean(sea),back-arc basin,intra-arc basin,marine rift,and continental rift basins.The source rocks in different sedimentary environ?ments show different geochemical characteristics,and can be divided into 5 types,including Well Wucan1 type source rock,Dishuiquan type source rock,Wucaicheng type source rock,Zaheba type source rock,and Dixi8 well type source rock.The hydrocarbon generation capacity of source rocks developed in different sedimentary environments have huge difference.Among them,the source rocks in back-arc basin and intra-arc basin show strong hydrocarbon generation capacity and are high-quality source rocks,and the generated hydrocarbon is an important exploration target。