Study on long-distance fixed-point sealed coring technology in broken-soft coal seam

Authors

LONG Weicheng, Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710077, ChinaFollow
SUN Siqing, Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710077, China
CHEN Jian, Huainan Mining Industry (Group) Corp., Ltd., Huainan 232001, China

Abstract

With the rapid development of mining, drilling and other technologies in the field of coal mine and the increasing demand for enhancing production and profit in the coal mine, the demand is increasingly urgent for detection of coal seam gas content in the initial stage. In recent years, the gas content measurement technology of underground long borehole high-pressure water sealed coring has been applied in the medium hard coal seam mining area with remarkable effects, but its application is limited in broken-soft coal seam. A number of issues are encountered that easy breakup of coal core sample, easy wall collapse of the bore hole, gas inrush from borehole, low success rate for coal sample coring, and large risk, when the existing coring technology through directional drilling and sealed high-pressure water is employed in the broken-soft coal seam. In order to solve the aforementioned issues and meet the demand of coal samples containing original moisture, a long-distance fixed-point closed coring technology process was proposed to use "gas coring drilling + gas conveying plugging ball + high-pressure water and gas combined sealing coal core" in the soft coal seam with double circulation medium. A long-distance dry closed coring system is proposed through downhole pressurized air sampling drilling, in which pressurized air is used instead of pressurized water for drilling slag discharge, core bit cooling and plugging ball transportation; air and water are combined to press. The sealed coring device in the hole is closed through the drive from a combination of wind and water. The main coal seam in the same area of a mine in Huainan mining area is selected for testing. The gas content of long-distance fixed-point closed coring in broken-soft coal seam is measured as 6.65~7.82 m³/t, while the gas content of conventional coring is measured as 5.11~6.45 m³/t. It is found that the gas content of airtight coring samples is generally higher than that of conventional coring samples. The research shows that the long-distance fixed-point closed coring technology in the broken-soft coal seam provides a new way to accurately measure the gas content in the broken-soft coal seam over a long-distance, thereby meeting the information demand for the gas occurrence information in the broken-soft coal seam in large areas and ensuring safe and efficient production in mines.

Keywords

sealed coring, fixed-point sampling, broken-soft coal seam, gas content, pressurized air drilling

DOI

10.12363/issn.1001-1986.21.12.0882

Recommended Citation

LONG Weicheng, SUN Siqing, CHEN Jian, et al. (2022) "Study on long-distance fixed-point sealed coring technology in broken-soft coal seam," Coal Geology & Exploration: Vol. 50: Iss. 8, Article 11.
DOI: 10.12363/issn.1001-1986.21.12.0882
Available at: https://cge.researchcommons.org/journal/vol50/iss8/11

Reference

[1] 袁亮. 深部采动响应与灾害防控研究进展[J]. 煤炭学报,2021,46(3):716−725. YUAN Liang. Research progress of mining response and disaster prevention and control in deep coal mines[J]. Journal of China Coal Society,2021,46(3):716−725.

[2] 袁亮. 我国深部煤与瓦斯共采战略思考[J]. 煤炭学报,2016,41(1):1−6. YUAN Liang. Strategic thinking of simultaneous exploitation of coal and gas in deep mining[J]. Journal of China Coal Society,2016,41(1):1−6.

[3] 谢和平,周宏伟,薛东杰,等. 煤炭深部开采与极限开采深度的研究与思考[J]. 煤炭学报,2012,37(4):535−542. XIE Heping,ZHOU Hongwei,XUE Dongjie,et al. Research and consideration on deep coal mining and critical mining depth[J]. Journal of China Coal Society,2012,37(4):535−542.

[4] 许耀波,朱玉双,张培河. 紧邻碎软煤层的顶板岩层水平井开发煤层气技术[J]. 天然气工业,2018,38(9):70−75. XU Yaobo,ZHU Yushuang,ZHANG Peihe. Application of CBM horizontal well development technology in the roof strata close to broken–soft coal seams[J]. Natural Gas Industry,2018,38(9):70−75.

[5] 龙威成. 煤层瓦斯含量测定过程气成分差异研究[J]. 安全与环境学报,2020,20(3):925−929. LONG Weicheng. Trace and determination of the gas compositional difference in the coal seam gas content testing[J]. Journal of Safety and Environment,2020,20(3):925−929.

[6] 王力,姚宁平,姚亚峰,等. 煤矿井下碎软煤层顺层钻完孔技术研究进展[J]. 煤田地质与勘探,2021,49(1):285−296. WANG Li,YAO Ningping,YAO Yafeng,et al. Research progress of drilling and borehole completion technologies in broken soft coal seam in underground coal mine[J]. Coal Geology & Exploration,2021,49(1):285−296.

[7] 刘建林,方俊,褚志伟,等. 碎软煤层空气泡沫复合定向钻进技术应用研究[J]. 煤田地质与勘探,2021,49(5):278−285. LIU Jianlin,FANG Jun,CHU Zhiwei,et al. Application of air foam composite directional drilling technology in broken soft coal seams[J]. Coal Geology & Exploration,2021,49(5):278−285.

[8] 张群,范章群. 煤层气损失气含量模拟试验及结果分析[J]. 煤炭学报,2009,34(12):1649−1654. ZHANG Qun,FAN Zhangqun. Simulation experiment and result analysis on lost gas content of coalbed methane[J]. Journal of China Coal Society,2009,34(12):1649−1654.

[9] SCHULTHEISS P J,FRANCIS T J G,HOLLAND M,et al. Pressure coring,logging and subsampling with the HYACINTH system[J]. Geological Society Special Publication,2006,267:151−163.

[10] 张洪君,刘春来,王晓舟,等. 深层保压密闭取心技术在徐深12井的应用[J]. 石油钻采工艺,2007,29(4):110−111. ZHANG Hongjun,LIU Chunlai,WANG Xiaozhou,et al. Application of submerged pressure maintaining sealed coring techniques to well Xushen 12[J]. Oil Drilling & Production Technology,2007,29(4):110−111.

[11] 孙四清,张群,龙威成,等. 煤矿井下长钻孔煤层瓦斯含量精准测试技术及装置[J]. 煤田地质与勘探,2019,47(4):1−5. SUN Siqing,ZHANG Qun,LONG Weicheng,et al. Accurate test technology and device for coal seam gas content in long boreholes in underground coal mines[J]. Coal Geology & Exploration,2019,47(4):1−5.

[12] 龙威成. 井下煤层长距离定点密闭取心技术及应用研究[J]. 河南理工大学学报(自然科学版),2022,41(1):9−16. LONG Weicheng. Research of long distance fixed–point sealed coring technology and application in underground coal seam[J]. Journal of Henan Polytechnic University (Natural Science),2022,41(1):9−16.

[13] 冯强,龙威成,李振福,等. 基于长距离密闭取心的煤巷条带瓦斯预抽效检研究[J]. 煤炭科学技术,2021,49(3):106−111. FENG Qiang,LONG Weicheng,LI Zhenfu,et al. Study on efficiency verification of strip in gas pre−drainage coal roadways based on long–distance sealed coring[J]. Coal Science and Technology,2021,49(3):106−111.

[14] 孙四清,张群,郑凯歌,等. 地面井煤层气含量精准测试密闭取心技术及设备[J]. 煤炭学报,煤炭学报,2020,45(7):2523−2530. SUN Siqing,ZHANG Qun,ZHENG Kaige,et al. Technology and equipment of sealed coring for accurate determination of coalbed gas content in ground well[J]. Journal of China Coal Society,2020,45(7):2523−2530.

[15] 芦伟,龙威成,康锴,等. 中硬煤层井下长距离密闭取心瓦斯含量测定技术应用研究[J]. 煤炭技术,2021,40(12):153−156. LU Wei,LONG Weicheng,KANG Kai,et al. Application of gas content measurement technology for long–distance sealed coring in medium hard coal seam[J]. Coal Technology,2021,40(12):153−156.

[16] 贵宏伟,李学臣,郭艳飞,等. 千米钻机超深钻孔定点密闭取芯技术研究与应用[J]. 煤炭工程,2018,50(12):54−57. GUI Hongwei,LI Xuechen,GUO Yanfei,et al. Research and application of fixed−point closed sampling technology for super deep drilling in 1 000 m drilling machine[J]. Coal Engineering,2018,50(12):54−57.

[17] 谢和平,高明忠,张茹,等. 深部岩石原位“五保”取芯构想与研究进展[J]. 岩石力学与工程学报,2020,39(5):865−876. XIE Heping,GAO Mingzhong,ZHANG Ru,et al. Study on concept and progress of in situ fidelity coring of deep rocks[J]. Chinese Journal of Rock Mechanics and Engineering,2020,39(5):865−876.