The Shahejie Formation in Huimin Sag is an important crude oil/natural gas reservoir stratum. The results show that (1) in the study area, the Sr/Ba value of Shahejie Formation ES4, ES3, and ES2 in Huimin Sag is 0.55–0.58, showing that these were freshwater-brackish water environment with a continental deposition; the average Sr/Ba value of the first member of Shahejie Formation (ES1) is 1.88, showing that it was a salt water environment. (2) B element method of paleo-salinity analysis shows that in ancient times, the salinity of ES1 was the highest; ES2 and ES4 had basically the same salinity that were lower than that of ES1; the third formation of Shahejie Formation(ES3) had the lowest salinity. (3) Analysis of values of Fe/Mn, Mg/Ca, and paleoclimate index C shows that the Shahejie Formation had generally a semi-dry climate. (4) Based on the analysis of the paleoenvironment, combined with the description of the cores, a sedimentary evolution model is built: ES4 was a debris flow fan-shaped river delta sediment in a shallow lake environment; ES3 was a delta-deep water fan-shaped system in a semi-deep-deep lake environment; ES2 was a delta system in semi-shallow lake environment; ES1 is the semi-shallow lake environment, the main sedimentary facies is the shore shallow lake facies.

惠民凹陷的沙河街组是重要的原油/天然气储层。结果表明：（1）研究区惠民凹陷沙河街组ES4，ES3和ES2的Sr / Ba值为0.55-0.58，表明该区为淡水微咸水环境，具有陆相沉积作用。沙河街组（ES1）第一段的平均Sr / Ba值为1.88，表明它是一个咸水环境。（2）古盐度分析的B元法表明，古代ES1的盐度最高。ES2和ES4具有基本相同的盐度，低于ES1；沙河街组第三组盐度最低。（3）对Fe / Mn，Mg / Ca和古气候指数C的分析表明，沙河街组总体上属于半干旱气候。（4）在古环境分析的基础上，结合岩心描述，建立了沉积演化模型：ES4为浅湖环境下泥石流扇状河三角洲沉积物。ES3是半深湖环境中的三角洲深水扇形系统。ES2是半浅湖环境中的三角洲系统；ES1是半浅湖环境，主要的沉积相是岸上浅湖相。