东营凹陷沙河街组一段沉积时期的湖泊古生产力

Study on palaeo-productivity of the lake during the deposition of the 1 member of Shahejie Formation in Dongying sag

李守军 王纪存 郑德顺 焦叶红 王金香 李学艳

Li Shoujun Wang Jicun Zheng Deshun Jiao Yehong Wang Jinxiang Li Xueyan

根据有机碳法计算湖泊古生产力的公式计算了东营凹陷沙河街组一段数百口井的古生产力值,做出了古生产力平面分布图,并与沙河街组三段沉积时期的古生产力以及现代不同营养类型湖泊的生产力进行了比较。研究表明,沙河街组三段中、下亚段和沙河街组一段沉积时期东营凹陷为超营养湖泊,是最有利于生油的湖泊;沙河街组三段上亚段沉积时期为富营养湖,也具有一定的生油能力。按生油岩的优劣程度排序,依次为沙河街组三段下亚段、沙河街组一段、沙河街组三段中亚段、沙河街组三段上亚段。

Palaeo productivity values of the 1 member of Shahejie Formation encountered in hundreds of wells in Dongying sag have been calculated with the formula of lake's productivity based on organic carbon method. The conture map shows the distribution of paleo productivity of the lake during the deposition of the 1 member of Shahejie Formation. These values are then compared with those of the 3 member of Shahejie Formation, as well as with those of modern lakes having different nutrition types. The study indicates that Dongying sag was a super eutrophic lake during the deposition of the middle and low intervals of the third member and the first member of Shahejie Formation, which would be the most favorable for oil generation. The sag was a eutrophic lake during the deposition of the upper interval of the third member of Shahejie Formation, which also had certain capacity of oil generation. The quality of source rocks degrades in a sequence from the low interval of the 3rd member to the 1st member, the middle interval and the upper interval of the 3rd member of Shahejie Formation.

10.11743/ogg20040611