Study of technologies and equipment of continuous hydraulic sand fracturing for permeability enhancement at high pressure side of coal mine downhole

Authors

JIA Bingyi, Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710077, China; College of Safety Science and Engineering, Xi’an University of Science and Technology, Xi’an 710054, ChinaFollow
LI Shugang, College of Safety Science and Engineering, Xi’an University of Science and Technology, Xi’an 710054, ChinaFollow
CHEN Dongdong, Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710077, China
LIN Haifei, College of Safety Science and Engineering, Xi’an University of Science and Technology, Xi’an 710054, China
ZHENG Kaige, State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China
SUN Siqing, State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China
ZHAO Jizhan, State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China

Abstract

The technological concept of sand fracturing at the high pressure side is proposed against the present situation where the coal mine downhole operation space is small, the power and water supply capacities are limited, and the surface sand fracturing equipment cannot be applied directly in the coal mine downhole. On the basis of the principle of sand mixing and carrying through hydrodynamic impact, the continuous hydraulic sand fracturing equipment at the high pressure side was developed. Such equipment requires no external power source for sand mixing. It forms cyclone impact through the changes in the flow regime and flow field of the fracturing fluid to realize sand mixing and carrying. As indicated by the theoretical analysis, numerical simulation and indoor simulation test, this equipment is feasible in principles, and can effectively mix and carry sand. The developed equipment has the overall pressure resistance of 55 MPa, 750 kg quartz sand can be loaded at one time, and can realize the continuous sand fracturing for a single crossing borehole or multiple crossing boreholes. The associated 3-channel shunt continuous hydraulic sand fracturing control system at the high pressure side of the coal mine downhole was designed. This system uses the mine compressed air to realize the on/off action of the switch, and coordinates with the fracturing pump control system to realize the remote concentrated control over the sand adding process, so as to ensure the safety and reliability during sand adding. The equipment was applied to carry out the field test for 5 floor crossing boreholes at the Pansan Coal Mine in Huainan Mining Area, Anhui. As indicated by the results, this equipment has high sand carrying capacity, and effective sand adding can be realized by only opening Channel II, with the maximum continuous sand adding amount of 150 kg and the maximum injected water amount of 316 m³. The gas extraction scalar quantity of the sand fracturing borehole and the gas extraction quantity of the 100 m borehole were 2.38 and 2.03 times of that of the water fracturing borehole, respectively, showing significant effects in permeability enhancement. The developed equipment can be applied in the fields, such as the coal mine downhole highpressure water jetting, hydraulic cutting and hydraulic sand fracturing.

Keywords

high pressure side, hydraulic sand fracturing, gas extraction, Pansan Coal Mine in Huainan, underground coal mine

DOI

10.12363/issn.1001-1986.22.03.0191

Recommended Citation

JIA Bingyi, LI Shugang, CHEN Dongdong, et al. (2022) "Study of technologies and equipment of continuous hydraulic sand fracturing for permeability enhancement at high pressure side of coal mine downhole," Coal Geology & Exploration: Vol. 50: Iss. 8, Article 7.
DOI: 10.12363/issn.1001-1986.22.03.0191
Available at: https://cge.researchcommons.org/journal/vol50/iss8/7

Reference

[1] 张群,葛春贵,李伟,等. 碎软低渗煤层顶板水平井分段压裂煤层气高效抽采模式[J]. 煤炭学报,2018,43(1):150−159. ZHANG Qun,GE Chungui,LI Wei,et al. A new model and application of coalbed methane high efficiency production from broken soft and low permeable coal seam by roof strata–in horizontal well and staged hydraulic fracture[J]. Journal of China Coal Society,2018,43(1):150−159.

[2] 徐凤银,闫霞,林振盘,等. 我国煤层气高效开发关键技术研究进展与发展方向[J]. 煤田地质与勘探,2022,50(3):1−14. XU Fengyin,YAN Xia,LIN Zhenpan,et al. Research progress and development direction of key technologies for efficient coalbed methane development in China[J]. Coal Geology & Exploration,2022,50(3):1−14.

[3] 姚艳斌,王辉,杨延辉,等. 煤层气储层可改造性评价:以郑庄区块为例[J]. 煤田地质与勘探,2021,49(1):119−129. YAO Yanbin,WANG Hui,YANG Yanhui,et al. Evaluation of the hydro–fracturing potential for coalbed methane reservoir:A case study of Zhengzhuang CBM field[J]. Coal Geology & Exploration,2021,49(1):119−129.

[4] 邹才能,杨智,董大忠,等. 非常规源岩层系油气形成分布与前景展望[J]. 地球科学,2022,47(5):1517−1533. ZOU Caineng,YANG Zhi,DONG Dazhong,et al. Formation,distribution and prospect of unconventional hydrocarbons in source rock strata in China[J]. Earth Science,2022,47(5):1517−1533.

[5] 孙四清,张群,闫志铭,等. 碎软低渗高突煤层井下长钻孔整体水力压裂增透工程实践[J]. 煤炭学报,2017,42(9):2337−2344. SUN Siqing,ZHANG Qun,YAN Zhiming,et al. Practice of permeability enhancement through overall hydraulic fracturing of long hole in outburst–prone soft crushed coal seam with low permeability[J]. Journal of China Coal Society,2017,42(9):2337−2344.

[6] 贾秉义,陈冬冬,吴杰,等. 煤矿井下顶板梳状长钻孔分段压裂强化瓦斯抽采实践[J]. 煤田地质与勘探,2021,49(2):70−76. JIA Bingyi,CHEN Dongdong,WU Jie,et al. Practice of enhanced gas extraction by staged fracturing with comb–shaped long hole in coal mine roof[J]. Coal Geology & Exploration,2021,49(2):70−76.

[7] 郑凯歌. 碎软低透煤层底板梳状长钻孔分段水力压裂增透技术研究[J]. 采矿与安全工程学报,2020,37(2):272−281. ZHENG Kaige. Permeability improving technology by sectional hydraulic fracturing for comb−like long drilling in floor of crushed and soft coal seam with low permeability[J]. Journal of Mining & Safety Engineering,2020,37(2):272−281.

[8] 陈冬冬,孙四清,张俭,等. 井下定向长钻孔水力压裂煤层增透技术体系与工程实践[J]. 煤炭科学技术,2020,48(10):84−89. CHEN Dongdong,SUN Siqing,ZHANG Jian,et al. Technology system and engineering practice of coal seam permeability improvement through underground directional long borehole hydraulic fracturing[J]. Coal Science and Technology,2020,48(10):84−89.

[9] 王生维,熊章凯,吕帅锋,等. 煤储层水力压裂裂缝中支撑剂特征及研究意义[J]. 煤田地质与勘探,2022,50(3):137−145. WANG Shengwei,XIONG Zhangkai,LYU Shuaifeng,et al. Characteristics and significance of proppant in hydraulic fractures in coal reservoirs[J]. Coal Geology & Exploration,2022,50(3):137−145.

[10] 巫修平,张群. 碎软低渗煤层顶板水平井分段压裂裂缝扩展规律及控制机制[J]. 天然气地球科学,2018,29(2):268−276. WU Xiuping,ZHANG Qun. Research on controlling mechanism of fracture propagation of multi–stage hydraulic fracturing horizontal well in roof of broken soft and low permeability coal seam[J]. Natural Gas Geoscience,2018,29(2):268−276.

[11] 董润平,张俭,闫志铭,等. 煤矿井下煤层顶板分段加砂压裂增渗技术与应用[J]. 煤矿安全,2022,53(5):73−80. DONG Runping,ZHANG Jian,YAN Zhiming,et al. Technology and application of sublevel sand fracturing and permeability enhancement of coal seam roof in underground coal mine[J]. Safety in Coal Mines,2022,53(5):73−80.

[12] 张俭，刘乐，王晨阳，等. 碎软突出煤层顶板定向长钻孔水力加砂分段压裂抽采瓦斯技术研究[R]. 西安：中煤科工集团西安研究院有限公司，2021.

[13] 陈建,贾秉义,董瑞刚,等. 煤矿井下水力压裂加骨料增透瓦斯抽采技术应用[J]. 煤炭工程,2021,53(2):90−94. CHEN Jian,JIA Bingyi,DONG Ruigang,et al. Application of hydraulic fracturing and aggregate injecting for permeability enhancement in underground coal mine gas extraction[J]. Coal Engineering,2021,53(2):90−94.

[14] 孙艳琦,牛文全. 文丘里管结构参数对其水力性能的影响[J]. 西北农林科技大学学报(自然科学版),2010,38(2):211−218. SUN Yanqi,NIU Wenquan. Effects of venturi structural parameters on the hydraulic performance[J]. Journal of Northwest A & F University (Natural Science Edition),2010,38(2):211−218.

[15] 甘德清,孙海宽,薛振林,等. 温度影响下的充填料浆大流量管输流态演化[J]. 中国矿业大学学报,2021,50(2):248−255. GAN Deqing,SUN Haikuan,XUE Zhenlin,et al. Transport state evolution of the packed slurry with the influence of temperature[J]. Journal of China University of Mining & Technology,2021,50(2):248−255.

[16] 禹言芳,王丰,孟辉波,等. 旋流静态混合器内瞬态流动特性研究进展[J]. 化工进展,2013,32(2):255−262. YU Yanfang,WANG Feng,MENG Huibo,et al. Research progress of the characteristics of instantaneous flow in static mixer with twisted–leaves[J]. Chemical Industry and Engineering Progress,2013,32(2):255−262.

[17] 卢义玉,李良伟,汤积仁,等. 前混合磨料水射流连续加料系统设计与实验研究[J]. 重庆大学学报,2018,41(8):111−120. LU Yiyu,LI Liangwei,TANG Jiren,et al. Design and experimental research of the continuous feeding system of premixed abrasive water jet[J]. Journal of Chongqing University,2018,41(8):111−120.

[18] 全国安全生产标准化技术委员会煤矿安全分技术委员会. 煤矿瓦斯抽放规范：AQ 1027—2006[S]. 北京：中国标准出版社，2006.