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学者们对饶阳凹陷烃源岩的研究已经取得了一些成果,但针对沙一下亚段烃源岩发育时期的古湖泊环境却缺乏系统的研究,忽略了湖泊环境这个控制烃源岩地球化学特征和时空展布的重要因素.通过对沙一下亚段烃源岩样品的古生物资料、有机地球化学、微量元素和同位素分析,恢复其古气候、湖泊古水深、古盐度、氧化还原条件和古生产力,综合这些影响因素建立了沙一下亚段优质烃源岩的发育模式.结果表明,沙一段下亚段(Es1下)的优质烃源岩多发育于湖侵体系域沉积期,气候正从干旱炎热向温暖潮湿转变,湖水深度约为2~14m,浪基面深度为7.5m;古盐度参数如Sr/Ba和B/Ga等都指示了沙一下亚段湖侵体系域沉积期属于咸水环境,形成了稳定的盐度分层,从而造成底层水处于稳定的缺氧条件,有利于有机质的保存;而稳定碳同位素和营养元素的分布特征都表明此阶段湖泊表层水体有较高的初始生产力.这样的古湖泊环境造成强还原咸水半深湖沉积的有机相分布较广,有利于优质烃源岩的发育.
Scholars have made some achievements in the research of source rocks in the Raoyang Sag. However, the lacustrine environment, the controlling geochemical characteristics of source rocks, lacks systematic study of the paleoenvironment during the development of source rock in sub-subscript Sha1. And spatiotemporal distribution.The paleoclimatic data, organic geochemistry, trace elements and isotopic analysis of source rock samples from the sub-first member of Shahe have restored their paleoclimate, ancient water depth of the lake, ancient salinity, redox conditions and ancient Productivity and comprehensively combining these influencing factors to establish the developmental model of high quality source rocks in the lower sub-sand of Shahejie.The results show that the high-quality source rocks in the lower sub-section Es1 of the first member of Shahejiechuan are mostly developed in the sedimentary period of the lake intrusive system and the climate is moving from The change of aridity to warm and wet, the depth of the lake is about 2 ~ 14m, the depth of the wave basal plane is 7.5m; the ancient salinity parameters such as Sr / Ba and B / Ga all indicate that the sedimentary period of the lacustrine system Salt water environment, the formation of a stable salinity stratification, resulting in bottom water in a stable anoxic conditions conducive to the preservation of organic matter; and stable carbon isotopes and nutrient elements of the distribution characteristics indicate that this stage of the lake Water layer has a higher initial productivity. Causes a strong reduction of the salty water deep lake sedimentary organic phase was widely distributed, facilitate development of source rocks such ancient lake environment.