Multi-scale differences in pore-fracture structures of coal reservoirs in the southern margin of the Junggar Basin and their influencing factors

doi:10.3969/j.issn.1006-6535.2026.04.004

Abstract

Abstract: Coalbed methane resources are abundant in the southern margin of the Junggar Basin(hereafter referred to as the southern Junggar Area),and are mainly hosted in the Jurassic Badaowan Formation and Xishanyao Formation.To clarify the differences in pore-fracture development characteristics and their influencing factors for coal reservoirs in the Badaowan Formation of the Fukang mining area and in the Xishanyao Formation of the Qigu fault-fold belt in the southern Junggar area,CT scanning,scanning electron microscopy (SEM),high-pressure mercury intrusion,low-temperature nitrogen adsorption and carbon dioxide adsorption experiments were conducted,and a full-aperture stitching technique was applied for analysis.The results show that the coals in the study area are all bituminous coals with similar reflectance and medium coal rank.The coal quality of the Fukang mining area(vitrinite content of 81%-88%)is slightly better than that of the Qigu fault-fold belt(vitrinite content of 70%-78%),while the coalification degree in the Qigu area is slightly higher.In the Fukang mining area,the coal reservoirs have few developed fractures;pores are dominated by tissue pores,with a small number of gas pores locally developed.The theoretical adsorption capacity is stronger with an average Langmuir volume of 18.75 cm³/g and an average specific surface area of 74.13 m²/g;however,affected by coal quality,the infilling effect of ash reduces the total pore volume pores are dominated by gas pores with higher proportions of mesopores and macropores.In the Qigu fault-fold belt, the average Langmuir volume is 10.83 cm³/g and the average specific surface area is 68.05 m²/g.Intensive tectonism provides conditions for fracture development;cleats and fractures are well developed overall,resulting in the advantageous reservoir physical properties of high porosity and permeability and low damage.Comprehensive analysis indicates that the Fukang mining area has better adsorption and high gas content,but fractures are not well developed,free gas is difficult to accumulate,and gas desorption is difficult;the Qigu Area has longer-term and more stable development potential.These results provide a theoretical basis for efficient exploration and development of coalbed methane in the study area.

Key words: coalbed methane, coal reservoir, digital core, pore-fracture structure, full-aperture characterization, southern margin of the Junggar Basin

CLC Number:

Li Wenjie, Wu Jinbiao, Long Yu, Ma Nenghui, Tian Ruixing, Liao Zhengkai, Kong Fang, Su Jingyi. Multi-scale differences in pore-fracture structures of coal reservoirs in the southern margin of the Junggar Basin and their influencing factors[J]. Special Oil & Gas Reservoirs, 2026, 33(4): 23-31.

References

[1] 毛新军,李艳平,梁则亮,等.准噶尔盆地侏罗系煤岩气成藏条件及勘探潜力[J].中国石油勘探,2024,29(4):31-43.
Mao Xinjun,Li Yanping,Liang Zeliang,et al.Hydrocarbon accumulation conditions and exploration potential of the Jurassic coal measure gas in Junggar Basin[J].China Petroleum Exploration,2024,29(4):31-43.
[2] 汤达祯,杨曙光,唐淑玲,等.准噶尔盆地煤层气勘探开发与地质研究进展[J].煤炭学报,2021,46(8):2412-2425.
Tang Dazhen,Yang Shuguang,Tang Shuling,et al.Advance on exploration-development and geological research of coalbed methane in the Junggar Basin[J].Journal of China Coal Society,2021,46(8):2412-2425.
[3] 兰浩,杨兆彪,仇鹏,等.新疆准噶尔盆地白家海凸起深部煤层气勘探开发进展及启示[J].煤田地质与勘探,2024,52(2):13-22.
Lan Hao,Yang Zhaobiao,Qiu Peng,et al.Exploration and exploitation of deep coalbed methane in the Baijiahai Uplift, Junggar Basin:progress and its implications[J].Coal Geology & Exploration,2024,52(2):13-22.
[4] 彭文利,薛冽,马效杰,等.准噶尔盆地南缘齐古地区煤层气地质特征[J].非常规油气,2021,8(1):8-14.
Peng Wenli,Xue Lie,Ma Xiaojie,et al.Geological characteristics of coalbed methane in Qigu Area on the southern margin of Junggar Basin[J].Unconventional Oil & Gas,2021,8(1):8-14.
[5] 张奥博.准噶尔盆地南缘西山窑组煤系气系统及其成藏效应研究[D].北京:中国地质大学(北京),2023:10-15.
Zhang Aobo.Study on the coal measure gas system of Xishanyao Formation and its accumulation effect in southern margin of Junggar Basin[D].Beijing:China University of Geosciences(Beijing),2023:10-15.
[6] 侯海海,李强强,梁国栋,等.准噶尔盆地南缘西山窑组与八道湾组煤层气成藏富集条件对比研究[J].非常规油气,2022,9(1):18-24.
Hou Haihai,Li Qiangqiang,Liang Guodong,et al.Comparative study of CBM accumulation conditions between the Xishanyao Formation and the Badaowan Formation in the southern Junggar Basin[J].Unconventional Oil & Gas,2022,9(1):18-24.
[7] 许婷,伏海蛟,马英哲,等.准噶尔盆地东南缘煤层气勘探目标优选[J].特种油气藏,2017,24(2):18-23.
Xu Ting,Fu Haijiao,Ma Yingzhe,et al.Selection of CBM exploration targets in southeastern margin of Junggar Basin[J].Special Oil & Gas Reservoirs,2017,24(2):18-23.
[8] 王鹏翔,张洲,余婉莹,等.深/浅部煤储层孔裂隙结构及三维空间分布差异特征——以准噶尔盆地为例[J].油气藏评价与开发,2025,15(2):227-236.
Wang Pengxiang,Zhang Zhou,Yu Wanying,et al.Characteristics of pore-fracture structure and three-dimensional spatial distribution differences in deep and shallow coal reservoirs:a case study of Junggar Basin[J].Petroleum Reservoir Evaluation and Development,2025,15(2):227-236.
[9] 李月云,江林华,张大伟,等.阜康矿区煤的孔隙与裂隙特征[J].煤田地质与勘探,2017,45(2):80-84.
Li Yueyun,Jiang Linhua,Zhang Dawei,et al.Characteristics of the pore and fracture in Fukang mining area[J].Coal Geology & Exploration,2017,45(2):80-84.
[10] 桑树勋,李瑞明,刘世奇,等.新疆煤层气大规模高效勘探开发关键技术领域研究进展与突破方向[J].煤炭学报,2024,49(1):563-585.
Sang Shuxun,Li Ruiming,Liu Shiqi,et al.Research progress and breakthrough directions of the key technical fields for large-scale and efficient exploration and development of coalbed methane in Xinjiang[J].Journal of China Coal Society,2024,49(1):563-585.
[11] 蒲一帆,汤达祯,唐淑玲,等.大倾角地质耦合条件下煤层气开发效果与地质评价[J].煤炭科学技术,2020,48(8):191-199.
Pu Yifan,Tang Dazhen,Tang Shuling,et al.Coalbed methane development effect and geological evaluation under large inclination angle geological coupling condition[J].Coal Science and Technology,2020,48(8):191-199.
[12] 卢杰林.不同煤阶煤孔径结构特征及全孔径拼接表征[D].徐州:中国矿业大学,2021:4-10.
Lu Jielin.Characterization of pore structure and full aperture splicing of coal with different coal ranks[D].Xuzhou:China University of Mining and Technology,2021:4-10.
[13] 陈彦君,苏雪峰,王钧剑,等.基于X射线微米CT扫描技术的煤岩孔裂隙多尺度精细表征——以沁水盆地南部马必东区块为例[J].油气地质与采收率,2019,26(5):66-72.
Chen Yanjun,Su Xuefeng,Wang Junjian,et al.Multi-scale fine characterization of coal pore-fracture structure based on X-ray micro-CT scanning:a case study of Mabidong Block,southern Qinshui Basin[J].Petroleum Geology and Recovery Efficiency,2019,26(5):66-72.
[14] 朱文涛,李小刚,任勇,等.基于CT扫描的煤岩孔隙结构全孔径表征[J].特种油气藏,2024,31(4):71-80.
Zhu Wentao,Li Xiaogang,Ren Yong,et al.Full pore size characterization of coal pore structure based on CT scanning[J].Special Oil & Gas Reservoirs,2024,31(4):71-80.
[15] 宋永,唐勇,何文军,等.准噶尔盆地油气勘探新领域、新类型及勘探潜力[J].石油学报,2024,45(1):52-68.
Song Yong,Tang Yong,He Wenjun,et al.New fields,new types and exploration potentials of oil gas exploration in Junggar Basin[J].Acta Petrolei Sinica,2024,45(1):52-68.
[16] 张玉垚.准噶尔盆地南缘阜康矿区煤储层非均质性研究[D].乌鲁木齐:新疆大学,2019:17-20.
Zhang Yuyao.Study on heterogeneity of coal reservoirs in Fukang mining area on the southern margin of Junggar Basin[D].Urumqi:Xinjiang University,2019:17-20.
[17] 何文军,费李莹,阿布力米提·依明,等.准噶尔盆地深层油气成藏条件与勘探潜力分析[J].地学前缘,2019,26(1):189-201.
He Wenjun,Fei Liying,Ablimiti Yiming,et al.Accumulation conditions of deep hydrocarbon and exploration potential analysis in Junggar Basin,NW China[J].Earth Science Frontiers,2019,26(1):189-201.
[18] Sing K.The use of nitrogen adsorption for the characterisation of porous materials[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects,2001,187/188:3-9.
[19] 张守鹏,方正伟,杨诗棣,等.全直径油气储层岩心三维可视化信息采集方法及应用前景[J].石油实验地质,2017,39(5):706-710.
Zhang Shoupeng,Fang Zhengwei,Yang Shidi,et al.Technique and application of three-dimensional visualized in formation collection of full diameter oil and gas reservoir cores[J].Petroleum Geology & Experiment,2017,39(5):706-710.
[20] 白斌,朱如凯,吴松涛,等.利用多尺度CT成像表征致密砂岩微观孔喉结构[J].石油勘探与开发,2013,40(3):329-333.
Bai Bin,Zhu Rukai,Wu Songtao,et al.Multi-scale method of Nano(Micro)-CT study on microscopic pore structure of tight sandstone of Yanchang Formation,Ordos Basin[J].Petroleum Exploration and Development,2013,40(3):329-333.
[21] Hutson N D,Yang R T.Theoretical basis for the Dubinin-Radushkevitch(D-R)adsorption isotherm equation[J].Adsorption,1997,3:189-195.
[22] 何余生,李忠,奚红霞,等.气固吸附等温线的研究进展[J].离子交换与吸附,2004,20(4):376-384.
He Yusheng,Li Zhong,Xi Hongxia,et al.Research progress of gas-solid adsorption isotherms[J].Ion Exchange and Adsorption,2004,20(4):376-384.
[23] 金振奎,王春生.煤层灰分对其储集性能的影响[J].天然气工业,2005,25(1):55-56,210.
Jin Zhenkui,Wang Chunsheng.Influence of coal ash content on coal reservoir behaviour[J].Natural Gas Industry,2005,25(1):55-56,210.
[24] 马超.准噶尔盆地南缘东部构造特征及形成演化[D].东营:中国石油大学(华东),2019:11-16.
Ma Chao.Structural characteristics,formation and evolution of the eastern part of the southern margin in the Junggar Basin[D].Dongying:China University of Petroleum(East China),2019:11-16.
[25] 吴伟,周永,冯阵东,等.准噶尔盆地齐古背斜深浅层泥岩裂缝发育差异性及其制约下油气保存条件[J].河南理工大学学报(自然科学版),2024,43(2):49-56.
Wu Wei,Zhou Yong,Feng Zhendong,et al.Differences in the development of deep and shallow mudstone fractures in Qigu anticline in the Junggar Basin and their constraints on oil and gas preservation conditions[J].Journal of Henan Polytechnic University(Natural Science),2024,43(2):49-56.
[26] 杨坤,王付勇,曾繁超,等.基于数字岩心分形特征的渗透率预测方法[J].吉林大学学报(地球科学版),2020,50(4):1003-1011.
Yang Kun,Wang Fuyong,Zeng Fanchao,et al.Permeability prediction based on fractal characteristics of digital rock[J].Journal of Jilin University(Earth Science Edition),2020,50(4):1003-1011.