| Citation: |
GUO Tao，JIN Xiaobo，WU Didi，et al. Accumulation characteristics and exploration prospects of deep coalbed methane in the Longtan Formation of the Nanchuan block on the southeastern margin of the Sichuan Basin[J]. Coal Geology & Exploration，2024，52(4)：60−67. DOI: 10.12363/issn.1001-1986.23.10.0684
|
Vertical well Y2 in the Nanchuan bloc on the southeastern margin of the Sichuan Basin has yielded daily production of natural flowing gas of 13000 m3, signifying a strategic breakthrough in deep coalbed methane (CBM) exploration on the margin. This study aims to systematically reveal the enrichment and high-yield patterns of CBM in the Nanchuan block. Using data on the regional geology, tests, assays, and production, this study investigated the accumulation characteristic and conducted exploration potential evaluation for deep CBM in the Nanchuan block from the perspective of the quality, pore and fissure characteristics, gas content, and fracability of coals. The results are as follows: (1) The deep coal reservoirs in the study area exhibit stable distribution, with thicknesses ranging from 1.5 m to 4.2 m and vitrinite reflectance (Rran) from 1.6% to 2.2%, establishing them coal seams with high Rran values and low ash content. These coal seams provide a material basis for CBM accumulation. (2) The coal reservoirs are of micro pore-micro and -fissure type, with micro-pores accounting for 78.4% and contributing 95% to the total specific surface area. These are conducive to CBM adsorption and preservation. Furthermore, these reservoirs exhibit well-developed micro-fractures, which are beneficial for fracturing and gas seepage. (3) The coal seams feature high gas content and rich free gas, with a total gas content ranging between 12 m3/t and 37 m3/t and free gas generally accounting for 24% to 36% of the deep CBM. The critical conversion depth of absorption is about 1500 m. (4) The deep coals exhibit small horizontal stress difference coefficients, favorable coal structures, strong stress barriers as roof, and small angles between natural cracks and the maximum principal stress, which contribute to high fracability. (5) Wide and gentle anticlines in the Dingshan and Lintanchang areas on basin margins emerge as favorable zones for deep CBM exploration. The results of this study will serve as a guide for deep CBM exploration on the southeastern margin of the Sichuan Basin and provide a reference for deep CBM exploration in similar basins.
| [1] |
姚红生,陈贞龙,何希鹏,等. 深部煤层气“有效支撑”理念及创新实践:以鄂尔多斯盆地延川南煤层气田为例[J]. 天然气工业,2022,42(6):97−106. DOI: 10.3787/j.issn.1000-0976.2022.06.009
YAO Hongsheng,CHEN Zhenlong,HE Xipeng,et al. “Effective support” concept and innovative practice of deep CBM in South Yanchuan Gas Field of the Ordos Basin[J]. Natural Gas Industry,2022,42(6):97−106. DOI: 10.3787/j.issn.1000-0976.2022.06.009
|
| [2] |
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.
|
| [3] |
杨秀春,徐凤银,王虹雅,等. 鄂尔多斯盆地东缘煤层气勘探开发历程与启示[J]. 煤田地质与勘探,2022,50(3):30−41.
YANG Xiuchun,XU Fengyin,WANG Hongya,et al. Exploration and development process of coalbed methane in eastern margin of Ordos Basin and its enlightenment[J]. Coal Geology & Exploration,2022,50(3):30−41.
|
| [4] |
周德华,陈刚,陈贞龙,等. 中国深部煤层气勘探开发进展、关键评价参数与前景展望[J]. 天然气工业,2022,42(6):43−51.
ZHOU Dehua,CHEN Gang,CHEN Zhenlong,et al. Exploration and development progress,key evaluation parameters and prospect of deep CBM in China[J]. Natural Gas Industry,2022,42(6):43−51.
|
| [5] |
秦勇,申建,王宝文,等. 深部煤层气成藏效应及其耦合关系[J]. 石油学报,2012,33(1):48−54. DOI: 10.7623/syxb201201006
QIN Yong,SHEN Jian,WANG Baowen,et al. Accumulation effects and coupling relationship of deep coalbed methane[J]. Acta Petrolei Sinica,2012,33(1):48−54. DOI: 10.7623/syxb201201006
|
| [6] |
秦勇,申建. 论深部煤层气基本地质问题[J]. 石油学报,2016,37(1):125−136.
QIN Yong,SHEN Jian. On the fundamental issues of deep coalbed methane geology[J]. Acta Petrolei Sinica,2016,37(1):125−136.
|
| [7] |
郭绪杰,支东明,毛新军,等. 准噶尔盆地煤岩气的勘探发现及意义[J]. 中国石油勘探,2021,26(6):38−49.
GUO Xujie,ZHI Dongming,MAO Xinjun,et al. Discovery and significance of coal measure gas in Junggar Basin[J]. China Petroleum Exploration,2021,26(6):38−49.
|
| [8] |
房大志,程泽虎,李佳欣. 渝东南地区超深部煤层气高效压裂技术及精细排采制度研究与实践[J]. 煤田地质与勘探,2022,50(5):50−56.
FANG Dazhi,CHENG Zehu,LI Jiaxin. Eefficient fracturing technology and fine drainage system of ultradeep coalbed methane in southeast Chongqing:A case study of NY1 well[J]. Coal Geology & Exploration,2022,50(5):50−56.
|
| [9] |
孙斌,张培先,高全芳,等. 川东南南川地区茅口组一段碳酸盐岩储层特征及富集模式[J]. 非常规油气,2022,9(3):21–31.
SUN Bin,ZHANG Peixian,GAO Quanfang,et al. Reservoir properties and accumulation mode of carbonate rocks in Mao1 Member of Nanchuan Area in southeast Sichuan[J]. Unconventional Oil & Gas,2022,9(3):21–31.
|
| [10] |
刘世奇,王鹤,王冉,等. 煤层孔隙与裂隙特征研究进展[J]. 沉积学报,2021,39(1):212–230.
LIU Shiqi,WANG He,WANG Ran,et al. Research Advances on Characteristics of Pores and Fractures in Coal Seams[J]. Acta Sedimentologica Sinica,2021,39(1):212–230.
|
| [11] |
赵迪斐,郭英海,毛潇潇,等. 基于压汞、氮气吸附与FE–SEM的无烟煤微纳米孔特征[J]. 煤炭学报,2017,42(6):1517−1526.
ZHAO Difei,GUO Yinghai,MAO Xiaoxiao,et al. Characteristics of macronanopores in anthracite coal based on mercury injection,nitrogen adsorption and FESEM[J]. Journal of China Coal Society,2017,42(6):1517−1526.
|
| [12] |
李曙光,王成旺,王红娜,等. 大宁−吉县区块深部煤层气成藏特征及有利区评价[J]. 煤田地质与勘探,2022,50(9):59−67.
LI Shuguang,WANG Chengwang,WANG Hongna,et al. Reservoir forming characteristics and favorable area evaluation of deep coalbed methane in Daning Jixian block[J]. Coal Geology & Exploration,2022,50(9):59−67.
|
| [13] |
陆小霞,黄文辉,陈燕萍,等. 沁水盆地南部深煤层孔隙结构特征[J]. 东北石油大学学报,2015,39(3):41−49.
LU Xiaoxia,HUANG Wenhui,CHEN Yanping,et al. Pore structure of deep coal seam in southern Qinshui Basin[J]. Journal of Northeast Petroleum University,2015,39(3):41−49.
|
| [14] |
杨峰,宁正福,胡昌蓬,等. 页岩储层微观孔隙结构特征[J]. 石油学报,2013,34(2):301−311. DOI: 10.1038/aps.2012.162
YANG Feng,NING Zhengfu,HU Changpeng,et al. Characterization of microscopic pore structures in shale reservoirs[J]. Acta Petrolei Sinica,2013,34(2):301−311. DOI: 10.1038/aps.2012.162
|
| [15] |
韩金轩,杨兆中,李小刚,等. 我国煤层气储层压裂现状及其展望[J]. 重庆科技学院学报,2012,14(3):53−55.
HAN Jinxuan,YANG Zhaozhong,LI Xiaogang,et al. Present situation and prospect of coalbed methane reservoir fracturing in China[J]. Journal of Chongqing University of Science and Technology,2012,14(3):53−55.
|
| [16] |
孟贵希. 地应力场特征及其对煤储层压力和渗透率的影响研究[J],中国煤炭地质,2017,29(3),21–28.
MENG Guixi. Study on ground stress field features and its impact on coal reservoir pressure and permeability[J]. Coal Geology of China,2017,29(3),21–28.
|
| [17] |
徐宏杰,桑树勋,易同生,等. 黔西地区煤层埋深与地应力对其渗透率控制机制[J]. 地球科学 (中国地质大学学报),201,39(11):1607–1616.
XU Hongjie,SANG Shuxun,YI Tongsheng,et al. Control mechanism of buried depth and insitu stress for coal reservoir permeability in western Guizhou[J]. Earth Science (Journal of China University of Geosciences),201,39(11):1607–1616.
|
| [18] |
郭涛. 贵州省织金区块岩脚向斜煤层气富集高产规律研究[J]. 煤田地质与勘探,2021,49(2):62−69.
GUO Tao. The enrichment and high yield law of CBM in Yanjiao syncline in Zhijin Block,Guizhou Province[J]. Coal Geology & Exploration,2021,49(2):62−69.
|
| [19] |
KRESSE O,COHEN C,WENG X,et al. Numerical modeling of hydraulic fracturing in naturally formations[C]//U. S. Symposium on Rock Mechanics. 2011:26–29.
|
| [20] |
郭涛,王运海. 延川南煤层气田2号煤层煤体结构测井评价及控制因素[J]. 煤田地质与勘探,2014,42(3):22−25. DOI: 10.3969/j.issn.1001-1986.2014.03.005
GUO Tao,WANG Yunhai. Evaluation of logging of coal texture of seam 2 in Yanchuannan gas field and analysis of its main controlling factors[J]. Coal Geology and Exploration,2014,42(3):22−25. DOI: 10.3969/j.issn.1001-1986.2014.03.005
|
| [21] |
陈守雨,刘建伟,龚万兴,等. 裂缝性储层缝网压裂技术研究及应用[J]. 石油钻采工艺,2010,32(6):67−71.
CHEN Shouyu,LIU Jianwei,GONG Wanxing,et al. Study and application on network fracturing technology in fractured reservoir[J]. Oil Drilling & Production Technology,2010,32(6):67−71.
|
| [22] |
路艳军. 煤岩体积压裂机理研究[D]. 成都:西南石油大学,2017.
LU Yanjun. Mechanism researches of stimulated reservoir volume in coal seams[D]. Chengdu:Southwest Petroleum University,2017.
|
| [23] |
王学太. 重庆市煤层气资源评价及开发利用建议[J]. 中国煤层气,1999(2):20−22.
WANG Xuetai. Evaluation of coalbed methane resources in Chongqing and suggestions for development and utilization[J]. China Coalbed Methane,1999(2):20−22.
|
| [24] |
姚红生,房大志,包凯,等. 渝东南地区龙潭组煤层气甜点地质评价及有效压裂工艺[J/OL]. 煤炭科学技术,1–9 [2024–03–17]. https://kns.cnki.net/kcms2/article/abstract?v=C06iYwc_NfQnUhrk8L4NsWFyF5rCWMMPwqciDeZpAw3uvumbsdiFxMWWXjY03wtoLkpcW75cJFEtz9NN67Jr65XErfgWYxfulSg9qzXb50vc0KLyG0l98L1YdhmnKAu51-t1OTILcOU=&;uniplatform=NZKPT&language=CHS.
YAO Hongsheng,FANG Dazhi,BAO Kai,et al. Geological evaluation and effective fracturing technology of coalbed methane sweet spots in the Longtan Formation of southeastern Chongqing[J/OL]. Coal Science and Technology:1–9[2024–03–17]. https://kns.cnki.net/kcms2/article/abstract?v=C06iYwc_NfQnUhrk8L4NsWFyF5rCWMMPwqciDeZpAw3uvumbsdiFxMWWXjY03wtoLkpcW75cJFEtz9NN67Jr65XErfgWYxfulSg9qzXb50vc0KLyG0l98L1YdhmnKAu51-t1OTILcOU=&;uniplatform=NZKPT&language=CHS.
|
Copyright of website design © Editorial Office of Coal Geology & Exploration 陕ICP备05001372号-6
陕公网安备 61019002002193号
Address: Editorial Office of Coal Geology & Exploration, No.82 Jinye 1st Rd, High-Tech Zone, Xi'an City, Shaanxi, China
Tel: 029-81778075 E-mail: ccrimtdzykt@vip.163.com
Supported by: Beijing Renhe Information Technology Co., Ltd. 
DownLoad: