(1. School of Mining and Technology，Inner Mongolia University of Technology，Hohhot，Inner Mongolia 010051，China；
2. State Key Laboratory of Coal and CBM Co-mining，Jinneng Holding Group，Jincheng，Shanxi 048204，China；
3. Faculty of Earth Resources，China University of Geosciences，Wuhan，Hubei 430074，China)
Abstract：The understanding of coal fracture behavior and loading rate effect on the scale of laboratory test is also helpful for the analysis of the fracture propagation law and the regulation of the fracturing fracture formation in the process of underground reservoir fracturing. The fracture behavior and loading rate effect of lignite semi-circular samples taken from Erlian Basin in Inner Mongolia were studied by SHPB test in the direction of bedding parallel，bedding vertical and bedding oblique direction. The results show that the fracture process of lignite samples from Erlian Basin under impact includes elastic deformation，fracture and unloading stages；with the increase of loading rate，the fracture strength and fracture toughness of the samples increase linearly，and the effect of loading rate on the fracture behavior of lignite in the study area is very significant. With the increase of loading rate，the degree of sample breakage intensifies. The bedding parallel type specimens is mainly in the form of bedding shear fracture under impact，and the vertical bedding and oblique bedding specimens are mainly in the form of impact crushing and form a large number of fractures. Coal fines is unfavorable for coalbed methane drainage. The fracture orientation of lignite under impact is basically consistent with the loading direction. Meanwhile，with the increase of the loading rate，the energy dissipation of the lignite fracture process in the study area increases linearly. The above shows that the fault behavior of lignite in Erlian Basin is deeply controlled by the loading rate. Finally，this paper proposes a control program for coal reservoir fracturing mode based on loading rate effect. Among them，the deep stress-controlled lignite reservoir fracturing is mainly used to increase the loading rate step by step from near to far，while the shallow lignite reservoir controlled by natural fractures is fracturing，and the fracturing is from near to far. The pumping procedure of decreasing the loading rate step by step makes the fracturing fractures mainly controlled by stress in the initial stage，and turned into the main control by natural fractures in the later stage. The effect of“staged”fracturing is to form main fractures in the near-wellbore zone，complex fractures in the middle and complex fractures at the far end.
陈立超1，2，王生维2，3，张典坤2，吕帅锋3. 二连盆地褐煤断裂行为加载率效应及对压裂裂缝调控的启示[J]. 岩石力学与工程学报, 2023, 42(S1): 3169-3177.
CHEN Lichao1，2，WANG Shengwei2，3，ZHANG Diankun2，LV Shuaifeng3. The loading rate effect of lignite fracture behavior in Erlian Basin and its enlightenment on the regulation of fracturing fractures. , 2023, 42(S1): 3169-3177.
[1] 王生维，陈立超. 煤储层水力压裂裂缝延展机制[M]. 武汉：中国地质大学出版社，2017：1–3.(WANG Shengwei，CHEN Lichao. Fracture propagation mechanism of hydraulic fracturing in coal reservoirs[M]. Wuhan：China University of Geosciences Press，2017：1–3.(in Chinese))
[2] 袁士义，宋新民，冉启全. 裂缝性油藏开发技术[M]. 北京：石油工业出版社，2004：76–81.(YUAN Shiyi，SONG Xinmin，RAN Qiquan. Development technology of fractured reservoirs[M]. Beijing：Petroleum Industry Press，2004：76–81.(in Chinese))
[3] 雷 群，管保山，才 博，等. 储集层改造技术进展及发展方向[J]. 石油勘探与开发，2019，46(3)：580–587.(LEI Qun，GUAN Baoshan，CAI Bo，et al. Technological progress and prospects of reservoir stimulation[J]. Petroleum Exploration and Development，2019，46(3)：580–587.(in Chinese))
[4] 石晓明，王冠民，熊周海，等. 纹层方向对泥页岩纵、横波速度及弹性参数影响的试验研究[J]. 岩石力学与工程学报，2019，38(8)：1 567–1 577.(SHI Xiaoming，WANG Guanmin，XIONG Zhouhai，et al. Experimental study on influence of laminae direction on P-wave and S-wave velocities and elastic parameters of shale[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(8)：1 567– 1 577.(in Chinese))
[5] 张 萍，杨春和，汪 虎，等. 页岩单轴压缩应力–应变特征及能量各向异性[J]. 岩土力学，2018，39(6)：2 106–2 114.(ZHANG Ping，YANG Chunhe，WANG Hu，et al. Stress-strain characteristics and anisotropy energy of shale under uniaxial compression[J]. Rock and Soil Mechanics，2018，39(6)：2 106–2 114.(in Chinese))
[6] SHANG J，GUI Y，ZHAO Z. Broad-spectrum fracture toughness of an anisotropic sandstone under mixed-mode loading[J]. Theoretical and Applied Fracture Mechanics，2018，96：556–575.
[7] JIN Z F，LI W X，JIN C R，et al. Anisotropic elastic，strength，and fracture properties of Marcellus shale[J]. International Journal of Rock Mechanics and Mining Sciences，2018，109：124–137.
[8] SUO Y，CHEN Z，RAHMAN S S，et al. Experimental and numerical investigation of the effect of bedding layer orientation on fracture toughness of shale rocks[J]. Rock Mechanics and Rock Engineering，2020，53：3 625–3 635.
[9] YU J，SHANG X C. Analysis of the influence of boundary pressure and friction on determining fracture toughness of shale using cracked Brazilian disc test[J]. Engineering Fracture Mechanics，2019，212：57–69.
[10] 孙清佩，张志镇，李培超，等. 黑色页岩动载破坏的层理效应及损伤本构模型研究[J]. 岩石力学与工程学报，2019，38(7)：1 319– 1 331.(SUN Qingpei，ZHANG Zhizhen，LI Peichao，et al. Study on the bedding effect and damage constitutive model of black shale under dynamic loading[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(7)：1 319–1 331.(in Chinese))
[11] GUPTA I，SONDERGELD C，RAI C. Fracture toughness in shales using nano-indentation[J]. Journal of Petroleum Science and Engineering，2020，191：107222.
[12] HUANG D，LI B，MA W Z，et al. Effects of bedding planes on fracture behavior of sandstone under semi-circular bending test[J]. Theoretical and Applied Fracture Mechanics，2020，108：102625.
[13] KRAMAROV V，PARRIKAR P N，MOKHTARI M. Evaluation of Fracture Toughness of Sandstone and Shale Using Digital Image Correlation[J]. Rock Mechanics and Rock Engineering，2020，53： 4 231–4 250.
[14] NIU Y，ZHOU X P，BERTO F. Evaluation of fracture mode classification in flawed red sandstone under uniaxial compression[J]. Theoretical and Applied Fracture Mechanics，2020，107：102528.
[15] FENG G，KANG Y，CHEN F，et al. The influence of temperatures on mixed-mode(I+II) and mode-II fracture toughness of sandstone[J]. Engineering Fracture Mechanics，2018，189：51–63.
[16] 龚 爽，赵毅鑫. 层理对煤岩动态断裂及能量耗散规律影响的试验研究[J]. 岩石力学与工程学报，2017，36(增2)：3 723–3 731.(GONG Shuang，ZHAO Yixin. Experimental study on effect of bedding on dynamic fracture and energy dissipation of coal and rock[J]. Chinese Journal of Rock Mechanics and Engineering，2017，36(Supp.2)： 3 723–3 731.(in Chinese))
[17] 陈立超，王生维. 煤岩断裂力学性质对储层压裂改造的影响[J]. 天然气地球科学，2020，31(1)：122–131.(CHEN Lichao，WANG Shengwei. Fracture properties of high-rank coal and its constraint on hydraulic fracturing stimulation of coal reservoir[J]. Natural Gas Geoscience，2020，31(1)：122–131.(in Chinese))
[18] 陈立超，王生维. 煤岩弹性力学性质与煤层破裂压力关系[J]. 天然气地球科学，2019，30(4)：503–511.(CHEN Lichao，WANG Shengwei. Relationship between elastic mechanical properties and dequivalent fracture press of coal reservoir near wellbore[J]. Natural Gas Geoscience，2019，30(4)：503–511.(in Chinese))
[19] 杨国梁，毕京九，郭伟民，等. 加载角度对层理页岩裂纹扩展影响的实验研究[J]. 爆炸与冲击，2021，41(9)：27–39.(YANG Guoliang，BI Jingjiu，GUO Weimin，et al. Experimental study on the effect of loading angle on crack propagation in bedding shale[J]. Explosion and Shock Waves，2021，41(9)：27–39.(in Chinese))
[20] 王兴渝，朱哲明，邱 豪，等. 冲击荷载下层理对页岩内裂纹扩展行为影响规律的研究[J]. 岩石力学与工程学报，2019，38(8)：1 542–1 556.(WANG Xingyu，ZHU Zheming，QIU Hao，et al. Study of the effect of stratifications on crack propagation behaviors in shale under impacting loads[J]. Chinese Journal of Rock Mechanics and Engineering，2019，38(8)：1 542–1 556.(in Chinese))
[21] ZHAO Y X，GONG S，HAO X J，et al. Effects of loading rate and bedding on the dynamic fracture toughness of coal：Laboratory experiments[J]. Engineering Fracture Mechanics，2017(178)：375–391.
[22] 宫凤强，王 进，李夕兵. 岩石压缩特性的率效应与动态增强因子统一模型[J]. 岩石力学与工程学报，2018，37(7)：1 586–1 595. (GONG Fengqiang，WANG Jin，LI Xibing. The rate effect of compression characteristics and a unified model of dynamic increasing factor for rock materials[J]. Chinese Journal of Rock Mechanics and Engineering，2018，37(7)：1 586–1 595.(in Chinese))
[23] 陈立超，王生维，张典坤. 基于SHPB实验的煤层气井固井水泥冲击能量耗散特征研究[J]. 材料导报，2021，35(增1)：232–237. (CHEN Lichao，WANG Shengwei，ZHANG Diankun. Research on the impact energy dissipation characteristics of cementing cement in coalbed methane wells based on SHPB experiment[J]. Materials Bulletin，2021，35(Supp.1)：232–237.(in Chinese))
[24] KURUPPU M D，CHONG K P. Fracture toughness testing of brittle materials using semi-circular bend(SCB) specimen[J]. Engineering Fracture Mechanics，2012，91：133–150.
[25] ZHOU Y X，XIA K，LI X B. Suggested methods for determining the dynamic strength parameters and mode-I fracture toughness of rock materials[J]. International Journal of Rock Mechanics and Mining Sciences，2012，49：105–112.
[26] 陈立超，王生维，张典坤. 煤岩脆性特征压痕法评价及储层改造意义[J]. 煤炭学报，2020，45(增2)：955–964.(CHEN Lichao，WANG Shengwei，ZHANG Diankun. Brittleness evaluation of coal rock based on Indentation method and the significance of coal reservoir stimulation[J]. Journal of China Coal Society，2020，45(Supp.2)：955–964.(in Chinese))
[27] 陈立超，王生维，何俊铧，等. 煤层气井近井压裂裂缝充填特征与堵塞机制[J]. 中国石油大学学报：自然科学版，2017，41(6)：117–122.(CHEN Lichao，WANG Shengwei，HE Junhua，et al. Filling characteristics and plugging mechanisms of hydraulic fractures near CBM vertical wells[J]. Journal of China University of Petroleum：Natural Science Edition，2017，41(6)：117–122.(in Chinese))
[28] 陈立超，王生维，张典坤. 内蒙古胜利煤田褐煤断裂特征半圆弯曲试验研究[J]. 煤炭科学技术，2023，DOI：10.13199/ j.cnki.cst. 2021–1313.(CHEN Lichao，WANG Shengwei，ZHANG Diankun. Experimental study on fracture behavior of lignite of Shengli coalfield and its fracturing significance[J]. Coal Science and Technology，2023，DOI：10.13199/ j.cnki.cst. 2 021–1 313.(in Chinese))
2023, Vol. 42 
