A log-based method for evaluating the tar yield of tar-rich coal

Authors

TIAN Han, College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China; Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, ChinaFollow
LI Ning, College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China; Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China
WANG Shuangming, Geological Research Institute for Coal Green Mining, Xi’an University of Science and Technology, Xi’an 710054, China
WU Hongliang, Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China
FENG Zhou, Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China
WANG Kewen, Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China
WANG Guiwen, College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, ChinaFollow

Abstract

Objective As a kind of coal-based oil and gas resource, tar-rich coal is significant for the supply of oil and gas resources, as well as the clean and efficient utilization of coals. Presently, the identification of tar-rich coals primarily depends on the Gray-King assay. In contrast, there is a lack of studies on the accurate identification and evaluation of tar-rich coal using geophysical methods. Methods This study investigated coals in the Jurassic Xishanyao and Badaowan Formations in Santanghu Basin, Xinjiang. Based on petrophysical experiments, as well as the typical log response characteristics of tar-rich coal, this study developed a new log-based method for quantitatively evaluating the tar yield of tar-rich coal. Results and Conclusions Key findings are as follows: (1) Compared to tar-bearing coal, tar-rich coal features a high content of materials with hydrogen-rich structures and unfavorable pore structures, which contribute to the log response characteristics of low density, high compensated neutron logging, and high resistivity. (2) The multistate 2D NMR experiments reveal that tar-rich coal is characterized by double peaks of the T₁ spectrum and strong signals in zones with T₂<1 and T₁/T₂>10, while oil-rich coal shows insignificant singles in these zones. This contrast is related to the high content of materials with hydrogen-rich structures in tar-rich coal. (3) Based on the log response characteristics of tar-rich coal, this study established indicator Z for tar-rich coal using resistivity and neutron log curves, with a higher Z value indicating higher tar yield of the coal. Building on tar yield calibration, this study determined the linear relationship between the coal tar yield and Z, achieving the accurate, convenient, and practical calculation of the tar yield of tar-rich coal. The above understanding offers theoretical guidance for identifying and evaluating tar-rich coal based on geophysical logs.

Keywords

tar-rich coal, tar yield, log response characteristic, nuclear magnetic resonance (NMR) log, evaluation method, Santanghu Basin

DOI

10.12363/issn.1001-1986.23.12.0844

Recommended Citation

TIAN Han, LI Ning, WANG Shuangming, et al. (2024) "A log-based method for evaluating the tar yield of tar-rich coal," Coal Geology & Exploration: Vol. 52: Iss. 7, Article 11.
DOI: 10.12363/issn.1001-1986.23.12.0844
Available at: https://cge.researchcommons.org/journal/vol52/iss7/11

Reference

[1] 王双明，师庆民，王生全，等. 富油煤的油气资源属性与绿色低碳开发[J]. 煤炭学报，2021，46(5)：1365−1377.

WANG Shuangming，SHI Qingmin，WANG Shengquan，et al. Resource property and exploitation concepts with green and low–carbon of tar–rich coal as coal–based oil and gas[J]. Journal of China Coal Society，2021，46(5)：1365−1377.

[2] 王双明，王虹，任世华，等. 西部地区富油煤开发利用潜力分析和技术体系构想[J]. 中国工程科学，2022，24(3)：49−57.

WANG Shuangming，WANG Hong，REN Shihua，et al. Potential analysis and technical conception of exploitation and utilization of tar–rich coal in western China[J]. Strategic Study of CAE，2022，24(3)：49−57.

[3] 师庆民，王双明，王生全，等. 神府南部延安组富油煤多源判识规律[J]. 煤炭学报，2022，47(5)：2057−2066.

SHI Qingmin，WANG Shuangming，WANG Shengquan，et al. Multi–source identification and internal relationship of tar–rich coal of the Yan’an Formation in the south of Shengfu[J]. Journal of China Coal Society，2022，47(5)：2057−2066.

[4] 东振，张梦媛，陈艳鹏，等. 三塘湖–吐哈盆地富油煤赋存特征与资源潜力分析[J]. 煤炭学报，2023，48(10)：3789−3805.

DONG Zhen，ZHANG Mengyuan，CHEN Yanpeng，et al. Analysis on the occurrence characteristics and resource potential of tar–rich coal in Santanghu and Turpan–Hami Basins[J]. Journal of China Coal Society，2023，48(10)：3789−3805.

[5] 马丽，王双明，段中会，等. 陕西省富油煤资源潜力及开发建议[J]. 煤田地质与勘探，2022，50(2)：1−8.

MA Li，WANG Shuangming，DUAN Zhonghui，et al. Potential of oil–rich coal resources in Shaanxi Province and its new development suggestion[J]. Coal Geology & Exploration，2022，50(2)：1−8.

[6] 谢青，李宁，姚征，等. 黄陵矿区富油煤焦油产率特征及主控地质因素分析[J]. 中国煤炭，2020，46(11)：83−90.

XIE Qing，LI Ning，YAO Zheng，et al. Research on the tar yield characteristics and main control factors of tar–rich coal in Huangling Mining Area[J]. China Coal，2020，46(11)：83−90.

[7] 王锐，夏玉成，马丽. 榆神矿区富油煤赋存特征及其沉积环境研究[J]. 煤炭科学技术，2020，48(12)：192−197.

WANG Rui，XIA Yucheng，MA Li. Study on oil–rich coal occurrence characteristics and sedimentary environment in Yushen Mining Area[J]. Coal Science and Technology，2020，48(12)：192−197.

[8] 李华兵，李宁，姚征，等. 陕北三叠纪煤田子长矿区瓦窑堡组特高焦油产率煤富集规律分析[J]. 中国煤炭地质，2021，33(1)：22−25.

LI Huabing，LI Ning，YAO Zheng，et al. Study on Wayaobu Formation extra–high tar yield coal enrichment pattern in Zichang Mining Area，Northern Shaanxi Triassic Coalfield[J]. Coal Geology of China，2021，33(1)：22−25.

[9] 许婷，李宁，姚征，等. 陕北榆神矿区富油煤分布规律及形成控制因素[J]. 煤炭科学技术，2022，50(3)：161−168.

XU Ting，LI Ning，YAO Zheng，et al. Distribution and geological controls of tar–rich coals in Yushen Mining Area of Northern Shaanxi[J]. Coal Science and Technology，2022，50(3)：161−168.

[10] 赵军龙，闫和平，王金锋，等. 基于测井信息的煤焦油产率预测方法研究[J]. 地球物理学进展，2023，38(4)：1702−1712.

ZHAO Junlong，YAN Heping，WANG Jinfeng，et al. Research on coal tar productivity prediction method based on logging information[J]. Progress in Geophysics，2023，38(4)：1702−1712.

[11] 李纪森. 煤层气测井技术与解释分析[J]. 测井技术，1999，23(2)：103−107.

LI Jisen. Logging technology and interpretation approach for coalbed gas[J]. Well Logging Technology，1999，23(2)：103−107.

[12] 潘和平. 煤层气储层测井评价[J]. 天然气工业，2005，25(3)：48−51.

PAN Heping. Evaluation coalbed methane reservoir by log data[J]. Natural Gas Industry，2005，25(3)：48−51.

[13] 张松杨. 煤层气地球物理测井技术现状及发展趋势[J]. 测井技术，2009，33(1)：9−15.

ZHANG Songyang. Actualities and progresses of coalbed methane geophysical logging technologies[J]. Well Logging Technology，2009，33(1)：9−15.

[14] 闫和平，段中会，王金锋. 黄陵矿区富油煤焦油产率与补偿密度关系模型预测方法研究[J]. 中国煤炭地质，2022，34(10)：25−30.

YAN Heping，DUAN Zhonghui，WANG Jinfeng. Study on the relationship model between oil–rich coal tar yield and compensation density in Huangling Mining Area[J]. Coal Geology of China，2022，34(10)：25−30.

[15] 王昌建，乔军伟. 基于BP神经网络的富油煤焦油产率预测[J]. 地质论评，2023，69(增刊1)：569−572.

WANG Changjian，QIAO Junwei. Rich coal tar yield prediction based on BP neural network[J]. Geological Review，2023，69(Sup.1)：569−572.

[16] 田瀚，冯周，王金锋，等. 陕西省煤岩焦油产率测井评价方法研究[J/OL]. 地球物理学进展，2023：1–13 [2024-03-25]. https://link.cnki.net/urlid/11.2982.P.20231109.1731.014.

TIAN Han，FENG Zhou，WANG Jinfeng，et al. Study on logging evaluation method of coal tar yield in Shaanxi Province[J/OL]. Progress in Geophysics，2023：1–13 [2024-03-25]. https://link.cnki.net/urlid/11.2982.P.20231109.1731.014.

[17] 李贤庆，钟宁宁，马安来，等. 三塘湖盆地侏罗纪煤系烃源岩的热演化研究[J]. 煤田地质与勘探，2003，31(1)：23−26.

LI Xianqing，ZHONG Ningning，MA Anlai，et al. A study on thermal evolution of organic matter in Jurassic coal–bearing source rocks of Santanghu Basin[J]. Coal Geology & Exploration，2003，31(1)：23−26.

[18] 黄卫东，李新宁，李留中，等. 三塘湖盆地煤层气资源勘探前景分析[J]. 天然气地球科学，2011，22(4)：733−737.

HUANG Weidong，LI Xinning，LI Liuzhong，et al. Prospect of coalbed methane exploration in Santanghu Basin[J]. Natural Gas Geoscience，2011，22(4)：733−737.

[19] 高绪晨，张春才，段铁梁. 煤层气测井资料解释初探[J]. 中国煤田地质，2003，15(4)：54−57.

GAO Xuchen，ZHANG Chuncai，DUAN Tieliang. Probe into interpretation on logging informations of coalbed gas[J]. Coal Geology of China，2003，15(4)：54−57.

[20] 毛志强，赵毅，孙伟，等. 利用地球物理测井资料识别我国的煤阶类型[J]. 煤炭学报，2011，36(5)：766−771.

MAO Zhiqiang，ZHAO Yi，SUN Wei，et al. Identification on the type of coal rank by using geophysical well logging data[J]. Journal of China Coal Society，2011，36(5)：766−771.

[21] 张广洋，谭学术，杜贵云，等. 煤的导电机理研究[J]. 湘潭矿业学院学报，1995，10(1)：15−18.

ZHANG Guangyang，TAN Xueshu，DU Guiyun，et al. Study on the mechanism of electricity conducting in coal[J]. Journal of Xiangtan Mining Institute，1995，10(1)：15−18.

[22] 刘之的，王伟，杨珺茹，等. 煤及煤层气储层导电特性研究综述与展望[J]. 地球物理学进展，2020，35(4)：1415−1423.

LIU Zhidi，WANG Wei，YANG Junru，et al. Review and prospect of study on conductive properties of coal and CBM reservoirs[J]. Progress in Geophysics，2020，35(4)：1415−1423.

[23] 陈鹏，王恩元，朱亚飞. 受载煤体电阻率变化规律的实验研究[J]. 煤炭学报，2013，38(4)：548−553.

CHEN Peng，WANG Enyuan，ZHU Yafei. Experimental study on resistivity variation regularities of loading coal[J]. Journal of China Coal Society，2013，38(4)：548−553.

[24] 李潮流，闫伟林，武宏亮，等. 富黏土页岩储集层含油饱和度计算方法：以松辽盆地古龙凹陷白垩系青山口组一段为例[J]. 石油勘探与开发，2022，49(6)：1168−1178.

LI Chaoliu，YAN Weilin，WU Hongliang，et al. Calculation of oil saturation in clay–rich shale reservoirs：A case study of Qing 1member of Cretaceous Qingshankou Formation in Gulong Sag，Songliao Basin，NE China[J]. Petroleum Exploration and Development，2022，49(6)：1168−1178.

[25] 谢然红，肖立志，邓克俊，等. 二维核磁共振测井[J]. 测井技术，2005，29(5)：430−434.

XIE Ranhong，XIAO Lizhi，DENG Kejun，et al. Two–dimensional NMR logging[J]. Well Logging Technology，2005，29(5)：430−434.

[26] KAUSIK R，FELLAH K，RYLANDER E，et al. NMR relaxometry in shale and implications for logging[J]. Petrophysics，2016，57(4)：339−350.

[27] SUN Yong，ZHAI Cheng，XU Jizhao，et al. A method for accurate characterization of the pore structure of a coal mass based on two–dimensional nuclear magnetic resonance T₁–T₂[J]. Fuel，2020，262：116574.

[28] LI Jinbu，JIANG Chunqing，WANG Min，et al. Adsorbed and free hydrocarbons in unconventional shale reservoir：A new insight from NMR T₁–T₂ maps[J]. Marine and Petroleum Geology，2020，116：104311.

[29] 徐宏武. 煤层电性参数测试及其与煤岩特性关系的研究[J]. 煤炭科学技术，2005，33(3)：42−46.

XU Hongwu. Measurement and test of seam electric parameter and study on relationship between seam electric parameter and coal petrology characteristics[J]. Coal Science and Technology，2005，33(3)：42−46.