南襄盆地泌阳凹陷古近系核桃园组页岩含油性及烃类赋存特征

Oil-bearing potential and hydrocarbon occurrence characteristics of shale in Paleogene Hetaoyuan Formation in Biyang Sag, Nanxiang Basin

金芸芸 李楚雄 王勇 严永新 罗曦 黄帅博 李志明 周圆圆 孙中良 刘雅慧 贾梦瑶 冷筠滢

JIN Yunyun LI Chuxiong WANG Yong YAN Yongxin LUO Xi HUANG Shuaibo LI Zhiming ZHOU Yuanyuan SUN Zhongliang LIU Yahui JIA Mengyao LENG Junying

1. 中国石化 河南油田分公司 勘探开发研究院, 河南 南阳 473132; 2. 中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126; 3. 页岩油气富集机理与高效开发全国重点实验室, 江苏 无锡 214126; 4. 中国石化 河南油田分公司 油气勘探管理部, 河南 南阳 473132

1. Research Institute of Exploration and Development, Henan Oilfield Company, SINOPEC, Nanyang, Henan 473132, China; 2. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China; 3. State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development, Wuxi, Jiangsu 214126, China; 4. Petroleum Exploration Management Department, Henan Oilfield Company, SINOPEC, Nanyang, Henan 473132, China

南襄盆地泌阳凹陷古近系核桃园组发育优质湖相页岩层系，页岩油资源潜力巨大。前人针对该层系页岩含油性及烃类赋存状态的研究相对薄弱，可能是制约泌阳凹陷页岩油勘探突破的重要因素之一。以泌阳凹陷南部Y1井核三段Ⅲ亚段页岩为研究对象，通过岩石热解、多温阶热解、X射线衍射等地球化学分析技术，系统开展了页岩含油性、烃类赋存特征及影响因素研究。研究结果显示：核三段Ⅲ亚段页岩岩相组合主要包括长英质页岩相、云灰质页岩相和混合质页岩相，纹层结构发育。烃源岩类型整体处于好—优质范围，热演化程度处于生油阶段。有机显微组分以腐泥型为主，有机质类型为Ⅰ—Ⅱ1型。页岩含油性随埋深增大呈递增趋势，烃类赋存特征由中上部以吸附烃为主，过渡至下部以游离烃为主。碎屑矿物及有机碳含量是控制游离烃和吸附烃含量的主要因素。总体认为，核桃园组下部页岩含油饱和度指数整体高于100 mg/g，游离烃含量平均高于3 mg/g，具备较好的页岩油勘探开发前景。

High-quality lacustrine shale beds within the Paleogene Hetaoyuan Formation in the Biyang Sag, Nanxiang Basin, exhibit significant potential for shale oil resources. Previous studies on the oil-bearing potential and hydrocarbon occurrence of shales in the Biyang Sag were relatively limited, potentially hindering advancements for shale oil exploration. This study focuses on the shales found in the third sub-member of the third member within the Hetaoyuan Formation in well Y1, which locates in the southern area of the Biyang Sag. Through various geochemical analyses such as Rock-Eval pyrolysis, multi-temperature pyrolysis and X-ray diffraction, this research systematically investigates the shale oil contents, hydrocarbon occurrence characteristics, and influencing factors. These results indicate that the lithofacies assemblages of the shale primarily consist of felsic shale facies, dolomitic shale facies and mixed shale facies, with a well-developed laminar structure. The source rock quality is classified as good to excellent, and the thermal maturity stage of oil window. The predominant organic maceral is sapropelic, with organic matter types ranging from Ⅰ to Ⅱ1. Oil content increases with burial depth, ranged from adsorbed hydrocarbons in the upper section to free hydrocarbons in the lower section. Detrital mineral content and total organic carbon (TOC) content are identified as the main factors influencing free and adsorbed hydrocarbon content, respectively. Overall, the oil saturation index (OSI) of the shale in the lower section of the Hetaoyuan Formation exceeds 100 mg/g, with an average free hydrocarbon content over 3 mg/g, indicating promising prospects for shale oil exploration and development.

国家自然科学基金项目(42090022)、中国石化“十四五”资源评价方法与数据库建设项目(P23229)、中国石化基础前瞻项目(P22211-4)、河南油田科技项目“陆相常压页岩油勘探关键技术”“泌阳凹陷页岩油赋存特征及主控因素研究”联合资助。

https://doi.org/10.11781/sysydz202402354