LU Yongxin，HU Shengyong，LI Guofu，et al. Experimental study and application of hydraulic fracturing in underlying coal seam[J]. Coal Science and Technology，2024，52（4）：231−242
. DOI: 10.12438/cst.2024-0286| Citation: |
LU Yongxin，HU Shengyong，LI Guofu，et al. Experimental study and application of hydraulic fracturing in underlying coal seam[J]. Coal Science and Technology，2024，52（4）：231−242 . DOI: 10.12438/cst.2024-0286
|
The coalbed methane resource under goaf is rich, but has not been effectively developed for a long time. Hydraulic fracturing technology stands as an effective means to augment coalbed methane recovery. The extraction and re-compaction of overlying coal seam will directly affect the expansion behavior of hydraulic fractures in the underlying coal seam. Though the large-scale (300 mm×300 mm×300 mm) true triaxial hydraulic fracturing experiments, the mechanical and acoustic emission response characteristics of coal were analyzed under different levels of loading and unloading stress perturbations. The damage variableTwas proposed to characterize the degree of coal damage, and the relationship between damage and the initiation and expansion patterns of hydraulic fractures was elucidated. The results revealed that, the damage induced by vertical stress loading in the underlying coal significantly exceeded that in the unloading stage. When the vertical loading stress was below 11 MPa, the coal remained in an elastic stage with minimal damage. Loading between 11~15 MPa corresponded to the yielding stage, witnessing a substantial increase in damage. Loading between 15~18 MPa led to the strengthening stage, the pores and fractures of coal were gradually compacted. Damage variablesTcan effectively characterize the degree of internal damage of coal. WhenT=Tc, the internal damage of coal was comparable to that of a coal that has not disturbed by loading and unloading stress.Tc is the damage variable of coal without loading and unloading stress disturbance. WhenT＞Tc , the coal exhibited a stress-damaged state, with higher values ofTcorresponding to increasing damage levels. Conversely, whenT＜Tc, the coal demonstrated a stress-compacted state, with smaller values ofTindicating higher compaction degrees. The degree of stress damage in coal was negatively correlated with the fracture pressure, a high degree of damage made coal more prone to fracture, and it was favor to form the primary hydraulic fractures near the wellbore, which was conducive to hydraulic fracturing. The degree of compaction of coal was positively correlated with fracture pressure. The high degree of compaction weakened the effect of horizontal stress difference on hydraulic fracture expansion, and the hydraulic fracture near the wellbore was more developed, which hindered the formation of primary hydraulic fractures. Based on the research results, the principle of hydraulic fracturing construction scheme optimization for underlying coal seam in goaf was formulated and applied in the field. The hydraulic fracturing ability of the optimized scheme was significantly improved.
| [1] |
刘 峰,郭林峰,赵路正. 双碳背景下煤炭安全区间与绿色低碳技术路径[J]. 煤炭学报,2022,47(1):1–15.
LIU Feng,GUO Linfeng ,ZHAO Luzheng. Research on coal safety range and green low-carbon technology path under the dual-carbon background [J]. Journal of China Coal Society,2022,47(1) :1–15.
|
| [2] |
王双明,申艳军,宋世杰,等. “双碳”目标下煤炭能源地位变化与绿色低碳开发[J]. 煤炭学报,2023,48(7):2599−2612.
WANG Shuangming,SHEN Yanjun,SONG Shijie,et al. Change of coal energy status and green and low-carbon development under the “dual carbon” goal[J]. Journal of China Coal Society,2023,48(7):2599−2612.
|
| [3] |
董灿灿,吕义清,刘志辉,等. 复杂地貌下行式开采地表移动变形规律[J]. 煤矿安全,2020,51(11):237−242.
DONG Cancan,LYU Yiqing,LIU Zhihui,et al. Surface movement and deformation law in downward mining of complex geomorphology[J]. Safety in Coal Mines,2020,51(11):237−242.
|
| [4] |
孟召平,李国富,田永东,等. 晋城矿区废弃矿井采空区煤层气地面抽采研究进展[J]. 煤炭科学技术,2022,50(1):204−211.
MENG Zhaoping,LI Guofu,TIAN Yongdong,et al. Research progress on surface drainage of coalbed methanein abandoned mine gobs of Jincheng mining area[J]. Coal Science and Technology,2022,50(1):204−211.
|
| [5] |
张江华,秦 勇,李国富,等. 煤炭采空区下伏煤层气资源潜力及抽采效果:以山西省晋城西部矿区为例[J]. 天然气工业,2022,42(6):146−153.
ZHANG Jianghua,QIN Yong,LI Guofu,et al. Potential and extraction effect of CBM resources underlying coal goafs:a case study on the western Jincheng mining area in Shanxi Province[J]. Natural Gas Industry,2022,42(6):146−153.
|
| [6] |
申鹏磊,吕帅锋,李贵山,等. 深部煤层气水平井水力压裂技术:以沁水盆地长治北地区为例[J]. 煤炭学报,2021,46(8):2488−2500.
SHEN Penglei,LYU Shuaifeng,LI Guishan,et al. Hydraulic fracturing technology for deep coalbed methane horizontal wells:a case study in North Changzhi area of Qinshui Basin [J]. Journal of China Coal Society,2021,46(8):2488−2500.
|
| [7] |
李全贵,邓羿泽,胡千庭,等. 煤岩水力压裂物理试验研究综述及展望[J]. 煤炭科学技术,2022,50(12):62−72.
LI Quangui,DENG Yize,HU Qianting,et al. Review and prospect of coal rock hydraulic fracturing physical experimental research[J]. Coal Science and Technology,2022,50(12):62−72.
|
| [8] |
CAO Wenzhuo,YILDIRIM B,DURUCAN S,et al. Fracture behaviour and seismic response of naturally fractured coal subjected to true triaxial stresses and hydraulic fracturing[J]. Fuel,2021,288:119618. doi: 10.1016/j.fuel.2020.119618
|
| [9] |
HUBBERT M K, WILLIS D G. Mechanics of hydraulic fracturing[J]. Transactions of the AIME,1957,210(1):153−168. doi: 10.2118/686-G
|
| [10] |
YU Beichen,LIU Chao,CHEN Weixing,et al. Experimental study on deformation and fracture characteristics of coal under different true triaxial hydraulic fracture schemes[J]. Journal of Petroleum Science and Engineering,2022,216:110839. doi: 10.1016/j.petrol.2022.110839
|
| [11] |
孟召平,卢易新. 高煤阶煤样水力压裂前后应力−渗透率试验研究[J]. 煤炭科学技术,2023,51(1):353−360.
MENG Zhaoping,LU Yixin. Experimental study on stress-permeability of high rank coal samples before and after hydraulic fracturing[J]. Coal Science and Technology,2023,51( 1):353−360.
|
| [12] |
李彦伟,朱超凡,曾壹坚,等. 层理特征对油页岩水力压裂裂缝扩展规律影响的数值模拟研究[J]. 煤田地质与勘探,2023,51(11):44−54.
LI Yanwei,ZHU Chaofan,ZENG Yijian,et al. Numerical simulations of the effects of bedding planes on hydraulic fracture propagation law in oil shale[J]. Coal Geology & Exploration,2023,51(11):44−54.
|
| [13] |
吕帅锋, 王生维, 刘洪太, 等. 煤储层天然裂隙系统对水力压裂裂缝扩展形态的影响分析[J]. 煤炭学报,2020,45(7):2590−2601.
LYU Shuaifeng, WANG Shengwei, LIU Hongtai, et al. Analysis of the influence of natural fracture system on hydraulic fracture propagation morphology in coal reservoir[J]. Journal of China Coal Society,2020,45(7):2590−2601.
|
| [14] |
DEHGHAN A N. An experimental investigation into the influence of pre-existing natural fracture on the behavior and length of propagating hydraulic fracture[J]. Engineering Fracture Mechanics,2020,240:107330. doi: 10.1016/j.engfracmech.2020.107330
|
| [15] |
FAN Tiegang,ZHANG Guagnqing,CUI Jinbang. The impact of cleats on hydraulic fracture initiation and propagation in coal seams[J]. Petroleum Science,2014,11:532−539. doi: 10.1007/s12182-014-0369-7
|
| [16] |
翟 成,郑仰峰,余 旭,等. 水力压裂模拟用煤岩体相似材料基础力学特性实验研究[J]. 煤田地质与勘探,2022,50(8):16−28.
ZHAI Cheng,ZHENG Yangfeng,YU Xu,et al. Experimental study on the mechanical properties of coal-like malterials for hydraulic fracturing simulation[J]. Coal Geology & Exploration,2022,50(8):16−28.
|
| [17] |
王永亮,刘娜娜,王 昊. 水力压裂分段射孔簇多裂缝空间偏转模拟研究[J]. 煤炭科学技术,2023,51(9):160−169.
WANG Yongliang,LIU Nana,WANG Hao. Simulation investigation on spatial deflection of multiples fractures of multistage perforation clusters in hydraulic fracturing[J]. Coal Science and Technology,2023,51(9):160−169.
|
| [18] |
张 帆,马 耕,刘 晓,等. 煤岩水力压裂起裂压力和裂缝扩展机制实验研究[J]. 煤田地质与勘探,2017,45(6):84−89.
ZHANG Fan,MA Geng,LIU Xiao,et al. Experimental study on initiation pressure and mechanism of fracture propagation of hydraulic fracturing in coal and rock mass[J]. Coal Geology & Exploration,2017,45(6):84−89.
|
| [19] |
李全贵,邓羿泽,胡千庭,等. 煤层水力压裂应力与裂隙演化的细观规律[J]. 煤田地质与勘探,2022,50(6):32−40.
LI Quangui,DENG Yize,HU Qianting,et al. Mesoscopic law of stress and fracture evolution of coal seams hydraulic fracturing[J]. Coal Geology & Exploration,2022,50(6):32−40.
|
| [20] |
LI Yanyan,HU Wei,ZHANG Zhizhong,ZHANG Zhaobin,et al. Numerical simulation of hydraulic fracturing process in a naturally fractured reservoir based on a discrete fracture network model[J]. Journal of Structural Geology,2021,147:104331. doi: 10.1016/j.jsg.2021.104331
|
| [21] |
XIE Jun,TANG Jizhou,YONG Rui,et al. A 3-D hydraulic fracture propagation model applied for shale gas reservoirs with multiple bedding planes[J]. Engineering Fracture Mechanics,2020,228:106872. doi: 10.1016/j.engfracmech.2020.106872
|
| [22] |
ZHOU Tong,WANG Haibo,LI Fengxia,et al. Numerical simulation of hydraulic fracture propagation in laminated shale reservoirs[J]. Petroleum Exploration and Development,2020,47(5):1117−1130. doi: 10.1016/S1876-3804(20)60122-7
|
| [23] |
HUANG Bingxiang,LIU Jiangwei. Experimental investigation of the effect of bedding planes on hydraulic fracturing under true triaxial stress[J]. Rock Mechanics and Rock Engineering,2017,50:2627−2643. doi: 10.1007/s00603-017-1261-8
|
| [24] |
李军军,李国富,郝海金,等. 过采空区抽采下组煤煤层气技术及工程应用初探:以晋城寺河井田为例[J]. 煤田地质与勘探,2021,49(4):96−104.
LI Junjun,LI Guofu,HAO Haijin,et al. Technology of across-goaf drainage of coalbed methane from a lower coal seam group and its primary application:taking Sihe mine field as an example[J]. Coal Geology & Exploration,2021,49(4):96−104.
|
| [25] |
刘亮亮,李国庆,李国富,等. 寺河井田采空区下伏煤层应力特征及其对煤层气开发的影响[J]. 煤炭学报,2022,47(4):1608−1619.
LIU Liangliang,LI Guoqing,LI Guofu,et al. Stress characteristics of coal seam underlying the goaf in the Sihe coalfield and its effect on the development of coalbed methane[J]. Journal of China Coal Society,2022,47(4):1608−1619.
|
| [26] |
沈荣喜,顾周杰,王恩元,等. 真三轴条件下煤样冲击动力学及破坏特征实验研究[J]. 煤炭学报,2023,48(5):2168−2178.
SHEN Rongxi,GU Zhoujie,WANG Enyuan,et al. Experimental study on impact dynamics and failure characteristics of coal specimen under true triaxial conditions[J]. Journal of China Coal Society,2023,48(5):2168−2178.
|
| [27] |
尹祥础,尹 灿. 非线性系统失稳的前兆与地震预报:响应比理论及其应用[J]. 中国科学 (B辑 化学 生命科学 地学),1991(5):512−518.
YIN Xiangchu, YIN Can. Precursors and earthquake prediction of instability in nonlinear systems: response ratio theory and its applications[J]. Science in China: Series B,1991(5):512−518.
|
Supported by: Beijing Renhe Information Technology Co., Ltd. 
DownLoad: