银额盆地巴北凹陷烃源岩地球化学特征与资源潜力

Geochemical characteristics and hydrocarbon resources potential of source rocks in Babei Sag， Yingen-Ejinaqi Basin

高怡文 郝世彦 王庆 王维波 江绍静 范庆雄 陈治军 周晔

Yiwen Gao Shiyan Hao Qing Wang Weibo Wang Shaojing Jiang Qingxiong Fan Zhijun Chen Ye Zhou

为明确银额盆地巴北凹陷烃源岩条件和油气资源潜力，基于研究区2口探井、1 143个泥岩样品的岩石热解和38个泥岩样品的系统测试分析资料，开展烃源岩地球化学特征研究，预测有效烃源岩的分布，分析研究区的油气资源潜力，以期为该区的勘探决策和勘探部署提供依据。结果表明：①研究区潜在烃源岩为发育于银根组（K）、苏红图组（K）、巴音戈壁组三段（K）、巴音戈壁组二段（K）、巴音戈壁组一段（K）和石炭系-二叠系（C-P）的泥岩，其中以K，K，K和C-P的有机质丰度为最高，有机质类型以Ⅱ-Ⅲ型为主，且高有机质丰度层段的烃源岩均达到了成熟-过成熟热演化阶段。②在有机质来源方面，高等植物对于各层段烃源岩具有较大的生源贡献。在沉积环境方面，各层段烃源岩均主要形成于弱还原-弱氧化的微咸水环境。③厘定了研究区有效烃源岩的总有机碳含量（）下限值为0.80 %，成熟生烃门限深度为1 100 m，有效烃源岩主要发育于K，K，K和C-P，其厚度在南、北两个次凹的沉积中心均较大。较好的烃源岩条件，加上活跃的油气显示，预示着研究区具有较好的油气资源潜力。

The source rocks and reservoirs in the Babei Sag， Yingen-Ejinaqi Basin， are assessed for geochemical characterization， effective source rock mapping and hydrocarbon potential analysis based on data from rock pyrolysis experiments of 1 143 mudstone samples and systematic tests of 38 mudstone samples from two local wells. The results show that potential source rocks are developed in mudstones of the Yingen Formation （K）， Suhongtu Formation （K）， the third， second and first members of the Bayingob Formation （K， K and K）， and Carboniferous-Permian （C-P） systems in the sag. Among them， the latter four （K， K， K and C-P） have higher organic matter abundance with type Ⅱ-typeⅢ kerogen of maturity and over-maturity. Higher plant made significant contribution to the organic carbon content in the source rocks and a weak reducing—weak oxidizing environment together with brackish water provided a setting for the source rocks to deposit. The source rocks in the sag are deemed effective when their is no less than 0.80 % and threshold depth for hydrocarbon generation is 1 100 m. Based on these criteria， effective source rocks in the sag are mainly developed in K， K， K and C-P and have the largest thickness in two sedimentary centers （northern subsag and southern subsag）. Good source rock conditions and active hydrocarbon shows indicate that the study area has good hydrocarbon exploration potential.

10.11743/ogg20220613