渤海湾盆地东濮凹陷胡古2井天然气地球化学特征与成因

Geochemical characteristics and types of natural gas from well Hugu 2 in the Dongpu Sag of Bohai Bay Basin

倪春华 包建平 周小进 许书堂 徐良发 徐田武 苏颂臣

Ni Chunhua Bao Jianping Zhou Xiaojin Xu Shutang Xu Liangfa Xu Tianwu Su Songchen

长江大学地球环境与水资源学院, 武汉 430100 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. 中国石化中原油田分公司勘探开发科学研究院, 郑州 450018

School of Earth Environment and Water Resources, Yangtze University, Wuhan, Hubei 430100, China 2. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China 3. Science Research Institute of Exploration and Development, SINOPEC Zhongyuan Oilfield, Zhengzhou, Henan 450018, China

东濮凹陷是中国东部地区典型的富含油气盆地,经过数十年的勘探已相继发现了一批油气田,近期在胡状集潜山钻探的胡古2井于二叠系上石盒子组、石千峰组试获工业气流。通过对胡古2井二叠系天然气地球化学特征的系统研究,同时结合区域地质背景资料,综合分析了其成因类型及来源。研究表明,该天然气烃类气体组成以甲烷为主,重烃气含量较低,干燥系数为0.977~0.985,属于干气;甲烷、乙烷、丙烷碳同位素值分别为-28.70‰~-28.40‰,-16.00‰~-14.50‰,-19.00‰~-15.70‰,且乙烷、丙烷碳同位素发生倒转,主要是由同源不同期的天然气混合所导致。胡古2井二叠系天然气属于煤成气,来自于石炭-二叠系煤系烃源岩,且喜马拉雅期高演化阶段生成的干酪根裂解气占主体。

The Dongpu Sag is a typical oil and gas producing unit in the Bohai Bay Basin in east China. A series of oil and gas fields have been discovered in recent years. In 2013, well Hugu 2 was drilled in the Huzhuangji area, finding industrial gas flows in the upper Shihezi and Shiqianfeng formations in the Permian. The geochemical characteristics and types of natural gas from well Hugu 2 were studied. The natural gas has a high methane content and low heavy hydrocarbon content. The dryness coefficient ranges from 0.977 to 0.985. The carbon isotopic values of methane, ethane and propane range from -28.7‰ to -28.4‰, -16.0‰ to -14.5‰, and -19.0‰ to -15.7‰, respectively. The carbon isotopic values of ethane and propane display reversal due to the mixing gases from the same source rocks at different stages. The gases from the Permian in well Hugu 2 are derived from the Carboniferous and Permian coal measures. A large proportion of the gases was cracked from kerogens during the Himalayan period.

中国石化油田勘探开发事业部重大勘探导向项目 (G5800-13-ZS-YTB027)资助。

https://doi.org/10.11781/sysydz201506764