阿尔金南缘山前侏罗系页岩气地质特征

Geological characteristics of the Jurassic shale gas play in the frontal area of the southern Altun Tagh

李伟奇 康志宏 周磊 童雪飞 皇甫静静

Li Weiqi Kang Zhihong Zhou Lei Tong Xuefei Huangfu Jingjing

中国地质大学(北京)能源学院, 北京 100083 2. 中国地质大学页岩气勘查与评价国土资源部重点实验室, 北京 100083

School of Energy Resources, China University of Geosciences, Beijing 100083, China 2. Key Laboratory for Shale Gas Exploration and Assessment, Ministry of Land and Resources, China University of Geosciences, Beijing 100083, China

阿尔金南缘山前侏罗系泥页岩发育,但页岩气勘探尚未涉及。以野外地质调查和岩心观察描述为基础,通过采样分析测试,厘定了阿尔金山前侏罗系泥页岩层段的分布和有机地化特征,识别出了有效页岩的赋存层位和分布区域。发育于半深湖环境的大煤沟组,是侏罗系泥页岩层段的主体,沿山前呈NE-SW向条带状展布。泥页岩总有机碳含量主要分布于1.00%~5.19%,有机质成熟度主要分布于1.11%~2.87%,有机质类型以Ⅱ1-Ⅱ2型为主。借鉴北美经验,认为山前大煤沟组泥页岩层厚较大,有机质丰度高,类型和热演化阶段适宜生气,页岩气发育的地质条件较好;月牙山区带、黑石山-三脚架区带、柴水沟-清水河区带以及茫崖1号沟区带为4个页岩气有利区。

The Jurassic shales were deposited in the frontal area of the southern margin of the Altun Tagh, but shale gas exploration or assessment has not be carried out. Some samples have been analyzed and tested using field geological surveys and core observation and description to determine the distribution and organic geochemical characteristics of shale layers in the Jurassic. Also the occurrence and distribution of effective shales in the frontal area of the Altun Tagh were identified. The Dameigou Formation, which forms the majority of the Jurassic shale layers, developed in a semi-deep lacustrine environment and shale was distributed in the NE-SW direction along the frontal area. Total organic carbon (TOC) ranges from 1.00% to 5.19% for high organic matter abundance, the organic matter maturity (Ro) varies from 1.11% to 2.87%, and the organic matter is dominated by type-Ⅱ1 kerogen to type-Ⅱ2 kerogen. The shale layers of the Dameigou Formation in the frontal area are thick, the abundance of organic matter is high, the type and the thermal evolution stage are favorable to produce gas, and comparison with North American deposits suggests that the geological conditions to accumulate shale gas are good. There are four favorable exploration targets for shale gas, including Yueyashan, Heishishan-Sanjiaojia, Chaishuigou-Qingshuihe, and Mangya areas.

国家自然科学基金项目(41272132)和中国地质调查局地质调查项目(12120113040000)资助。

https://doi.org/10.11781/sysydz201602178