Characteristics of shallow coal measure gas reservoir and key technologies of exploration and development in Yaojie mining area

Authors

DU Xinfeng, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
YUAN Chongliang, Yaojie Coal and Power Group Co. Ltd., Lanzhou 730080, China
WANG Zhengxi, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
WANG Junde, Yaojie Coal and Power Group Co. Ltd., Lanzhou 730080, China
LI Shibing, Yaojie Coal and Power Group Co. Ltd., Lanzhou 730080, China
LIU Jingdan, Yaojie Coal and Power Group Co. Ltd., Lanzhou 730080, China
HE Xiuqing, Yaojie Coal and Power Group Co. Ltd., Lanzhou 730080, China
ZHANG Tianguo, Yaojie Coal and Power Group Co. Ltd., Lanzhou 730080, China
SHAN Yuanwei, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
FANG Jiawei, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China

Abstract

The exploration and development of coal measures gas can not only effectively improve the single well production of coalbed methane in coal mining areas, reduce the waste of resources, but also alleviate the energy crisis in China, reduce coal mine gas accidents, protect the atmospheric environment, and contribute to the realization of carbon peak and carbon neutralization. Based on the shallow coal measure gas development demonstration project in the third mining area of Haishiwan mine field, the characteristics of coal measure gas reservoirs in Yaojie mining area are analyzed, and the key technologies for coal-measure gas exploration and development are discussed. The research showed that coal measure gas in the mine field is mainly present in the oil shale and oil sandstone of the fourth rock group(J₂yj⁴) of the Jurassic Yaojie Formation coal system, and the oil A layer and the second coal layer of the second group(J₂yj²). The gas content of oil layer A and second coal layer increases with the increase of burial depth; The CO₂ concentration in oil layer A and second coal layer is higher, and decreases with the increase of burial depth; The second coal layer has a strong adsorption capacity, and the oil layer A is easier to desorb; Oil sandstone permeability > oil layer A permeability > second coal layer permeability > oil shale permeability; Compressive strength, tensile strength, elastic modulus, Poisson's ratio and brittleness index show that the difficulty of reformation of them in descending order is oil sandstone, oil layer A, oil shale, and coal second layer; The organic matter abundance of oil shale is 4.06%, and kerogen type is Ⅱ₂-Ⅲ. The abundance of organic matter in the oil layer A is 43.27%, and the degree of metamorphism is polarized. The saprolite vitrinite reflectance is 0.48%-0.53%, and the humic coal vitrinite reflectance is 0.89%-0.97%. The abundance of organic matter in the second layer of coal is 92.87%, including vitrinite 67.90%, inertinite 29.10%, exinite 3.5%, the degree of metamorphism is mainly fat coal with a small amount of gas fat coal; Compared with most low pressured formations in China, the reservoir pressure of each producing layer is normal and the gas production potential is great; The second coal layer o, the oil layer A and the oil shale should be optimized in the development of coal measure gas. The fracturing technology of multiple clusters, flow-limiting perforating technology and fine sand filtration loss, ball drop temporary plugging, two large and one low(large displacement, large sand volume, low sand ratio) fracturing technology are suitable for the reservoir transformation of the ultra-thick and tight formation in this area, and the pump hanging position is lower than the two-layer perforating section of coal and the gravity spiral gas anchor drainage process can reduce the effect of CO₂ and improve the drainage efficiency. The application of these key technologies has significantly improved the gas production effect of the mine field demonstration project. The daily gas production of a single well exceeds 2 000 m³

Keywords

coal measure gas, reservoir characteristics, exploration and development, Yaojie mining area, Jurassic

DOI

10.3969/j.issn.1001-1986.2021.06.006

Recommended Citation

DU Xinfeng, YUAN Chongliang, WANG Zhengxi, et al. (2021) "Characteristics of shallow coal measure gas reservoir and key technologies of exploration and development in Yaojie mining area," Coal Geology & Exploration: Vol. 49: Iss. 6, Article 7.
DOI: 10.3969/j.issn.1001-1986.2021.06.006
Available at: https://cge.researchcommons.org/journal/vol49/iss6/7

Reference

[1] ZOU Caineng, YANG Zhi, HUANG Shipeng, et al. Resource types, formation, distribution and prospects of coal measure gas[J]. Petroleum Exploration and Development, 2019, 46(3): 21-30. 邹才能, 杨智, 黄士鹏, 等. 煤系天然气的资源类型、形成分布与发展前景[J]. 石油勘探与开发, 2019, 46(3): 433-442.

[2] WANG Xiaojing, HU Zhengzhou, LI Yanping, et al. Characteristic and exploration potential of deep coal measure gas assemblage in Jurassic of Junggar Basin[J]. Coal Technology, 2020, 39(9): 60-64. 汪孝敬, 胡正舟, 李艳平, 等. 准噶尔盆地侏罗系深部煤系气控制因素及勘探潜力[J]. 煤炭技术, 2020, 39(9): 60-64.

[3] BI Caiqin, SHAN Yansheng, PANG Bo, et al. High gas coal reservoir drilled in coal resource exhausted mining areas of Jixi Basin[J]. Geology in China, 2018, 45(6): 1306-1307. 毕彩芹, 单衍胜, 逄礴, 等. 鸡西盆地煤炭资源枯竭矿区钻获高含气量煤系储层[J]. 中国地质, 2018, 45(6): 1306-1307.

[4] CAO Daiyong, YAO Zheng, LI Jing. Evaluation status and development trend of unconventional gas in coal measure[J]. Coal Science and Technology, 2014, 42(1): 89-92. 曹代勇, 姚征, 李靖. 煤系非常规天然气评价研究现状与发展趋势[J]. 煤炭科学技术, 2014, 42(1): 89-92.

[5] QIN Yong, LIANG Jianshe, SHEN Jian, et al. Gas logging shows and gas reservoir types in sandstones and shales from southern Qinshui Basin[J]. Journal of China Coal Society, 2014, 39(8): 1559-1565. 秦勇, 梁建设, 申建, 等. 沁水盆地南部致密砂岩和页岩的气测显示与气藏类型[J]. 煤炭学报, 2014, 39(8): 1559-1565.

[6] WANG Tong, WANG Qingwei, FU Xuehai. The significance and the systematic research of the unconventional gas in coal measures[J]. Coal Geology & Exploration, 2014, 42(1): 24-27. 王佟, 王庆伟, 傅雪海. 煤系非常规天然气的系统研究及其意义[J]. 煤田地质与勘探, 2014, 42(1): 24-27.

[7] YI Tongsheng, ZHOU Xiaozhi, JIN Jun. Reservoir formation characteristics and co-exploration and concurrent production technology of Longtan coal measure coalbed methane and tight gas in Songhe field, western Guizhou[J]. Journal of China Coal Society, 2016, 41(1): 212-220. 易同生, 周效志, 金军. 黔西松河井田龙潭煤系煤层气-致密气成藏特征及共探共采技术[J]. 煤炭学报, 2016, 41(1): 212-220.

[8] QIN Yong, WU Jianguang, LI Guozhang, et al. Patterns and pilot project demonstration of coal measures gas production[J]. Journal of China Coal Society, 2020, 45(7): 2513-2522. 秦勇, 吴建光, 李国璋, 等. 煤系气开采模式探索及先导工程示范[J]. 煤炭学报, 2020, 45(7): 2513-2522.

[9] ZHANG Huquan. Geological conditions for Minhe Basin reservoirs[J]. Prospector, 1998, 3(1): 20-23. 张虎权. 民和盆地油气藏形成地质条件[J]. 勘探家, 1998, 3(1): 20-23.

[10] SU Qin, LI Xinning, YU Fazheng, et al. The favorable exploration target of shale gas in Tuha Basin[J]. Science and Technology and Engineering, 2011, 11(27): 6573-6577. 苏琴, 李新宁, 于法政, 等. 民和盆地页岩气勘探潜力分析[J]. 科学技术与工程, 2011, 11(27): 6573-6577.

[11] WEI Pingsheng, WANG Xinmin. Coal seam gas characteristics and geological conditions of Minhe Basin[J]. Natural Gas Industry, 1997, 17(4): 19-22. 卫平生, 王新民. 民和盆地煤层气特征及形成地质条件[J]. 天然气工业, 1997, 17(4): 19-22.

[12] XIAO Xianming, CHEN Zhongkai, JIN Kuili. The petrological characteristics of sapropelic coals in China[J]. Coal Geology & Exploration, 1990, 18(1): 7-13. 肖贤明, 陈中凯, 金奎励. 中国腐泥煤的岩石学特征[J]. 煤田地质与勘探, 1990, 18(1): 7-13.

[13] XIAO Xianming, CHENG Dingsheng. Studies on the coalification of sapropelic coals[J]. Coal Geology & Exploration, 1992, 20(2): 25-33. 肖贤明, 程顶胜. 腐泥煤的煤化作用研究[J]. 煤田地质与勘探, 1992, 20(2): 25-33.

[14] ZHOU Jiyong, XIONG Junjie, LIU Chunxiang, et al. The study of technologies for fracturing fluid leakoff control[J]. Inner Mongolia Petrochemical Industry, 2014, 40(12): 111-114. 周际永, 熊俊杰, 刘春祥, 等. 压裂液降滤失技术研究[J]. 内蒙古石油化工, 2014, 40(12): 111-114.

[15] LIU Guangqi, MA Lianxiang, LIU Jie, et al. Chemical data manual: Inorganic volumes[M]. Beijing: Chemical Industry Press, 2002. 刘光启, 马连湘, 刘杰, 等. 化学化工物性数据手册(无机卷)[M]. 北京: 化学工业出版社, 2002.

[16] DU Xinfeng, GUO Shengqiang, ZHANG Qun, et al. Separate-layer pressure control and multi-layer drainage technology and device for coalbed methane wells with multiple seams[J]. Coal Science and Technology, 2018, 46(6): 114-118. 杜新锋, 郭盛强, 张群, 等. 多煤层煤层气井分层控压合层排采技术及装备[J]. 煤炭科学技术, 2018, 46(6): 114-118.