在宜昌兴山下三叠统嘉陵江组灰岩晶洞和方解石脉中发现液体油苗.为查明其源岩,通过详细的野外剖面资料及密集采样,以有机碳含量0.5,为有效烃源岩下限,甄别出宜昌地区有三套有效烃源岩.通过烃源岩地球化学特征分析,发现萜烷、常规甾烷、甲藻甾烷等常规生物标志物的组成和分布趋于一致.高演化阶段的趋同性.已无法区分各套烃源岩,不能用于油源对比.但从三芳甾烷的组成和干酪根、氯仿沥青"A"稳定碳同位素组成特征.可以区分这三套烃源岩.油苗特征与上奥陶统五峰组一下志留统龙马溪组下部源岩相似,推测油苗来源于此源岩.

Oil seepage contained in the Lower Triassic Jialingjiang limestone was found at Xiakou in Yichang,Hubei Province. The characteristics of terpane, sterane and dinosteranes in source rocks have been analyzed. The result shows that owing to similarly tending original characteristics of routine biomarkers in three sets of source rocks from this area by maturation, composition and distribution, these source rocks that are used to correlated with the oil seepage cannot be distinguished from each other in high maturation stage,which means that the routine biomarkers cannot be applied in oil-source rock correlation. Triaromatic-sterane series compound that was once applied in oil-source rock correlation in high maturation area were discussed in literatures. According to composition of triaromatic-sterane series compounds, stable carbon isotope of kerogen, bitumen “A” and oil seepage in the Lower Triassic Jialingjiang Formation, it is conclude that the Jialingjiang oil derived from the Upper Ordovician Wufeng Formation—Lower Silurian Longmaxi Formation shale.