Characteristics and control modes of geothermal fields in deep coal reservoirs in the Linxing-Shenfu block

Authors

XU Lifu, CNOOC Research Institute Co., Ltd., Beijing 100028, ChinaFollow
BAI Yuhu, CNOOC Research Institute Co., Ltd., Beijing 100028, China
XU Bingxiang, CNOOC Research Institute Co., Ltd., Beijing 100028, China
HU Weiqiang, CNOOC EnerTech-Drilling & Production Co. Ltd., Tianjin 300457, China
CHEN Jianqi, CNOOC EnerTech-Drilling & Production Co. Ltd., Tianjin 300457, China
LI Yong, College of Geosciences and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

Abstract

Objective Geothermal fields serve as a crucial geological condition controlling the phases and seepage of deep coalbed methane (CBM). Investigating geothermal fields facilitates the assessment and efficient development of deep CBM resources.Methods This study explored the Nos. 8 and 9 coal seams in the Linxing-Shenfu block using data from drilling, well logging, well tests, and experiments. Specifically, this study summarized the regional distribution patterns of geothermal fields in deep coal reservoirs in the block, analyzed the impacts of the geothermal fields on the gas-bearing and physical properties of the reservoirs, and revealed the controlling factors and mechanisms of the geothermal fields. Furthermore, it proposed differential control modes of regional geothermal fields in the block.Results and Conclusions The results indicate that coal seams in the study area have a present-day average temperature of about 52 ℃ and geothermal gradients ranging from 1.72 ℃/hm to 2.64 ℃/hm (average: 2.21 ℃/hm), suggesting slightly low to normal geothermal gradients. The geothermal fields in the study area are negatively correlated with the adsorption capacity and mechanical properties of coal seams but are weakly positively correlated with their permeability. Specifically, higher geothermal gradients and reservoir temperatures correspond to lower critical depths of gas content in coal seams, a higher amount of adsorbed gas converted to free gas, and improved reservoir permeability. In contrast, higher geothermal gradients are associated with lower peak strength, smaller modulus of elasticity, and enhanced plasticity of coals. The geothermal fields in the study area are influenced by multiple factors, including burial depth, structures, groundwater, and the thermal conductivity of rocks. The small differences in the lateral thermal conductivity of strata result in the lateral heat transfer, followed by heat accumulation in uplift zones. As a result, high-temperature geothermal fields are formed. In contrast, faults destroy strata or connect groundwater, leading to thermal diffusion. Consequently, lower-temperature geothermal fields are formed. Four temperature control modes of geothermal fields in the study area are identified: (1) The universal mode with temperature controlled by horizontal strata, characterized by normal geothermal gradients but reservoir temperatures varying with the burial depth. (2) The mode with temperature primarily governed by lateral heat transfer, occurring in Zijinshan basement uplift. (3) The mode with temperature primarily influenced by faults, observed in the northern Linxing and western Shenfu blocks. (4) The composite mode with temperature dominated by both faults and groundwater, occurring in the eastern Shenfu block. This study reveals the distribution patterns of geothermal fields in the study area and their impacts on the physical properties of deep coal reservoirs. Under similar geological conditions, structurally higher parts with high-temperature geothermal fields are more enriched in free gas. Therefore, it is recommended that these parts serve as significant zones for resource assessment to promote the high production of deep CBM.

Keywords

deep coal reservoir, geotemperature field, gas-bearing property, mechanical property, geotemperature control mode

DOI

10.12363/issn.1001-1986.24.12.0795

Recommended Citation

XU Lifu, BAI Yuhu, XU Bingxiang, et al. (2025) "Characteristics and control modes of geothermal fields in deep coal reservoirs in the Linxing-Shenfu block," Coal Geology & Exploration: Vol. 53: Iss. 5, Article 8.
DOI: 10.12363/issn.1001-1986.24.12.0795
Available at: https://cge.researchcommons.org/journal/vol53/iss5/8

Reference

[1] 刘震，朱文奇，孙强，等. 中国含油气盆地地温–地压系统[J]. 石油学报，2012，33(1)：1−17.

LIU Zhen，ZHU Wenqi，SUN Qiang，et al. Characteristics of geotemperature–geopressure systems in petroliferous basins of China[J]. Acta Petrolei Sinica，2012，33(1)：1−17.

[2] 孟召平，禹艺娜，李国富，等. 沁水盆地煤储层地温场条件及其低地温异常区形成机理[J]. 煤炭学报，2023，48(1)：307−316.

MENG Zhaoping，YU Yina，LI Guofu，et al. Geothermal field condition of coal reservoir and its genetic mechanism of low geothermal anomaly area in the Qinshui Basin[J]. Journal of China Coal Society，2023，48(1)：307−316.

[3] 谢鸣谦. 地热流对石油生成的控制作用[J]. 石油学报，1981，2(1)：41−48.

XIE Mingqian. The controlling role of terrestrial heat flow in the genesis of petroleum[J]. Acta Petrolei Sinica，1981，2(1)：41−48.

[4] 任战利，崔军平，祁凯，等. 深层、超深层温度及热演化历史对油气相态与生烃历史的控制作用[J]. 天然气工业，2020，40(2)：22−30.

REN Zhanli，CUI Junping，QI Kai，et al. Control effects of temperature and thermal evolution history of deep and ultra–deep layers on hydrocarbon phase state and hydrocarbon generation history[J]. Natural Gas Industry，2020，40(2)：22−30.

[5] NADEAU P H，SUN Shaoqing，EHRENBERG S N. The “Golden Zone” temperature distribution of oil and gas occurrence examined using a global empirical database[J]. Marine and Petroleum Geology，2023，158：106507.

[6] 郭旭升，胡宗全，李双建，等. 深层–超深层天然气勘探研究进展与展望[J]. 石油科学通报，2023，8(4)：461−474.

GUO Xusheng，HU Zongquan，LI Shuangjian，et al. Progress and prospect of natural gas exploration and research in deep and ultra–deep strata[J]. Petroleum Science Bulletin，2023，8(4)：461−474.

[7] GUO Xusheng，HU Dongfeng，LI Yuping，et al. Theoretical progress and key technologies of onshore ultra–deep oil/gas exploration[J]. Engineering，2019，5(3)：458−470.

[8] 黄少英，胡方杰，张科，等. 塔里木盆地中央隆起超深层现今地温场特征[J]. 地质学报，2022，96(11)：3955−3966.

HUANG Shaoying，HU Fangjie，ZHANG Ke，et al. Present–day geotemperature field of superdeep layers in the Central Uplift，Tarim Basin[J]. Acta Geologica Sinica，2022，96(11)：3955−3966.

[9] 刘雨晨，柳波，朱焕来，等. 松辽盆地现今地温场分布特征及主控因素[J]. 地质学报，2023，97(8)：2715−2727.

LIU Yuchen，LIU Bo，ZHU Huanlai，et al. The distribution characteristics and main controlling factors of present–day geothermal regime of the Songliao Basin[J]. Acta Geologica Sinica，2023，97(8)：2715−2727.

[10] 李丹，常健，邱楠生，等. 塔北–阿满北部地区超深层现今地温场特征[J]. 地球物理学报，2023，66(8)：3353−3373.

LI Dan，CHANG Jian，QIU Nansheng，et al. Present–day superdeep thermal regime of the Tabei–northern Aman area in the Tarim Basin，northwest China[J]. Chinese Journal of Geophysics，2023，66(8)：3353−3373.

[11] 郗兆栋，唐书恒，刘忠，等. 宁武盆地深部煤储层地温场特征及其对含气性的影响[J]. 煤田地质与勘探，2024，52(2)：92−101.

XI Zhaodong，TANG Shuheng，LIU Zhong，et al. Deep coal reservoirs in the Ningwu Basin：Geothermal field characteristics and their effects on gas–bearing properties[J]. Coal Geology & Exploration，2024，52(2)：92−101.

[12] 李勇，高爽，吴鹏，等. 深部煤层气游离气含量预测模型评价与校正：以鄂尔多斯盆地东缘深部煤层为例[J]. 石油学报，2023，44(11)：1892−1902.

LI Yong，GAO Shuang，WU Peng，et al. Evaluation and correction of prediction model for free gas content in deep coalbed methane：A case study of deep coal seams in the eastern margin of Ordos Basin[J]. Acta Petrolei Sinica，2023，44(11)：1892−1902.

[13] 孟召平，任华鑫，禹艺娜，等. 沁水盆地南部煤储层赋存环境条件及其对渗透率的影响[J]. 煤炭学报，2024，49(1)：545−554.

MENG Zhaoping，REN Huaxin，YU Yina，et al. Geological conditions of coal reservoir occurrence in the southern Qinshui Basin and its impact on permeability[J]. Journal of China Coal Society，2024，49(1)：545−554.

[14] 秦勇. 中国深部煤层气地质研究进展[J]. 石油学报，2023，44(11)：1791−1811.

QIN Yong. Progress on geological research of deep coalbed methane in China[J]. Acta Petrolei Sinica，2023，44(11)：1791−1811.

[15] 高向东，王延斌，倪小明，等. 临兴地区深部煤岩力学性质及其对煤储层压裂的影响[J]. 煤炭学报，2020，45(增刊2)：912−921.

GAO Xiangdong，WANG Yanbin，NI Xiaoming，et al. Mechanical properties of deep coal and rock in Linxing area and its influences on fracturing of deep coal reservoir[J]. Journal of China Coal Society，2020，45(Sup.2)：912−921.

[16] 李勇，徐立富，张守仁，等. 深煤层含气系统差异及开发对策[J]. 煤炭学报，2023，48(2)：900−917.

LI Yong，XU Lifu，ZHANG Shouren，et al. Gas bearing system difference in deep coal seams and corresponded development strategy[J]. Journal of China Coal Society，2023，48(2)：900−917.

[17] 徐凤银，王成旺，熊先钺，等. 鄂尔多斯盆地东缘深部煤层气成藏演化规律与勘探开发实践[J]. 石油学报，2023，44(11)：1764−1780.

XU Fengyin，WANG Chengwang，XIONG Xianyue，et al. Evolution law of deep coalbed methane reservoir formation and exploration and development practice in the eastern margin of Ordos Basin[J]. Acta Petrolei Sinica，2023，44(11)：1764−1780.

[18] 郭广山，徐凤银，刘丽芳，等. 鄂尔多斯盆地府谷地区深部煤层气富集成藏规律及有利区评价[J]. 煤田地质与勘探，2024，52(2)：81−91.

GUO Guangshan，XU Fengyin，LIU Lifang，et al. Enrichment and accumulation patterns and favorable area evaluation of deep coalbed methane in the Fugu area，Ordos Basin[J]. Coal Geology & Exploration，2024，52(2)：81−91.

[19] 刘建忠，朱光辉，刘彦成，等. 鄂尔多斯盆地东缘深部煤层气勘探突破及未来面临的挑战与对策：以临兴–神府区块为例[J]. 石油学报，2023，44(11)：1827−1839.

LIU Jianzhong，ZHU Guanghui，LIU Yancheng，et al. Breakthrough，future challenges and countermeasures of deep coalbed methane in the eastern margin of Ordos Basin：A case study of Linxing–Shenfu Block[J]. Acta Petrolei Sinica，2023，44(11)：1827−1839.

[20] 徐长贵，季洪泉，王存武，等. 鄂尔多斯盆地东缘临兴–神府区块深部煤层气富集规律与勘探对策[J]. 煤田地质与勘探，2024，52(8)：1−11.

XU Changgui，JI Hongquan，WANG Cunwu，et al. Enrichment patterns and exploration countermeasures of deep coalbed methane in the Linxing–Shenfu Block on the eastern margin of the Ordos Basin[J]. Coal Geology & Exploration，2024，52(8)：1−11.

[21] 曾泉树，汪志明. 鄂尔多斯盆地东缘煤岩渗透率的应力和温度敏感特征[J]. 石油科学通报，2020，5(4)：512−519.

ZENG Quanshu，WANG Zhiming. Stress and temperature sensitivity of coal permeability in the eastern Ordos Basin[J]. Petroleum Science Bulletin，2020，5(4)：512−519.

[22] 李勇，徐立富，刘宇，等. 深部煤层气水赋存机制、环境及动态演化[J]. 煤田地质与勘探，2024，52(2)：40−51.

LI Yong，XU Lifu，LIU Yu，et al. Occurrence mechanism，environment and dynamic evolution of gas and water in deep coal seams[J]. Coal Geology & Exploration，2024，52(2)：40−51.

[23] 张凯，汤达祯，陶树，等. 不同变质程度煤吸附能力影响因素研究[J]. 煤炭科学技术，2017，45(5)：192−197.

ZHANG Kai，TANG Dazhen，TAO Shu，et al. Study on influence factors of adsorption capacity of different metamorphic degree coals[J]. Coal Science and Technology，2017，45(5)：192−197.

[24] 张兵，徐文军，徐延勇，等. 鄂尔多斯盆地东缘临兴区块深部关键煤储层参数识别[J]. 煤炭学报，2016，41(1)：87−93.

ZHANG Bing，XU Wenjun，XU Yanyong，et al. Key parameters identification for deep coalbed methane reservoir in Linxing Block of eastern Ordos Basin[J]. Journal of China Coal Society，2016，41(1)：87−93.

[25] 高亚楠，高峰，谢晶，等. 温度–围压–瓦斯压力作用下煤岩力学性质及有限变形行为[J]. 煤炭学报，2021，46(3)：898−911.

GAO Yanan，GAO Feng，XIE Jing，et al. Mechanical properties and finite deformation behavior of coal under temperature，confining pressure and gas pressure[J]. Journal of China Coal Society，2021，46(3)：898−911.

[26] 米洪刚，吴见，彭文春，等. 神府区块深部煤储层力学特性及裂缝扩展机制[J]. 煤田地质与勘探，2024，52(8)：32−43.

MI Honggang，WU Jian，PENG Wenchun，et al. Mechanical characteristics and fracture propagation mechanism of deep coal reservoirs in the Shenfu Block[J]. Coal Geology & Exploration，2024，52(8)：32−43.

[27] 唐博宁，邱楠生，朱传庆，等. 松辽盆地岩石热导率柱及古地温场分布特征[J]. 煤田地质与勘探，2024，52(1)：26−35.

TANG Boning，QIU Nansheng，ZHU Chuanqing，et al. Thermal conductivity column of rocks and distribution characteristics of paleo–geothermal field in the Songliao Basin[J]. Coal Geology & Exploration，2024，52(1)：26−35.

[28] 李宗星，高俊，李文飞，等. 柴达木盆地地温场分布特征及控制因素[J]. 地学前缘，2016，23(5)：23−32.

LI Zongxing，GAO Jun，LI Wenfei，et al. The characteristics of geothermal field and controlling factors in Qaidam Basin，northwest China[J]. Earth Science Frontiers，2016，23(5)：23−32.

[29] 陈刚，丁超，徐黎明，等. 鄂尔多斯盆地东缘紫金山侵入岩热演化史与隆升过程分析[J]. 地球物理学报，2012，55(11)：3731−3741.

CHEN Gang，DING Chao，XU Liming，et al. Analysis on the thermal history and uplift process of Zijinshan intrusive complex in the eastern Ordos Basin[J]. Chinese Journal of Geophysics，2012，55(11)：3731−3741.

[30] 宋嘉佳，王贵玲，邢林啸，等. 岩石热导率校正对大地热流计算值的影响：以渤海湾盆地冀中坳陷为例[J]. 地质论评，2023，69(4)：1349−1364.

SONG Jiajia，WANG Guiling，XING Linxiao，et al. Influence of rock thermal conductivity correction on the calculated value of terrestrial heat flow：A case study of Jizhong Depression，Bohai Bay Basin[J]. Geological Review，2023，69(4)：1349−1364.