为揭示水力压裂破岩机理,采用真三轴加载系统、声发射仪、高压柱塞泵建立了一套室内岩石水力压裂物理模拟系统,该系统可以研究水力压裂破岩机理。基于格里菲斯强度准则建立了岩石起裂的临界水压力和起裂位置,结果表明:当水压力远低于临界压力时,在水压上升期砂岩声发射特征较明显,在水压保持期砂岩声发射特征平静,产生的信号为砂岩原生闭合的微裂隙被压开;当水压力接近临界压力时,在水压上升期和保持期砂岩声发射撞击数、振幅、能量均聚增,产生的信号为砂岩破裂产生的新生裂隙扩展和贯通;裂缝起裂、扩展方向与最小主应力方向垂直,原生裂缝控制了砂岩的裂缝起裂和扩展方向。本研究成果可为煤矿细砂岩厚老顶强矿压水力压裂治理提供参考。
In order to reveal the rock breaking mechanism of hydraulic fracturing, a set of indoor rock hydraulic fracturing physical simulation system was established by using a true triaxial loading system, acoustic emission instrument and high pressure piston pump, which can study the rock breaking mechanism of hydraulic fracturing. Based on the Griffith strength criterion, the critical water pressure and the location of rock fracture initiation are established. The experimental results are as follows: When the water pressure is far below the critical pressure, the acoustic emission characteristics of sandstone are more obvious in the rising period of water pressure, and the acoustic emission characteristics of sandstone are quiet in the maintaining period of water pressure, and the signal is that the primarily closed microfractures of sandstone are pressed open; When the water pressure is close to the critical pressure, the impact number, amplitude and energy of acoustic emission of sandstone increase in the rising period and maintaining a period of water pressure, and the signal is the expansion and coalescence of new fissures caused by sandstone fracture; The direction of fracture initiation and propagation is perpendicular to the direction of the minimum principal stress, and the primary fractures control the direction of fracture initiation and propagation. The research results provide a reference for the hydraulic fracturing treatment of coal mine fine sandstone thick main roof.
[1]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 physical test of hydraulic fracturing of coal and rock[J]. Coal Science and Technology, 2022, 50 (12): 62-72. (in Chinese))
[2]王一可. 页岩气勘探开发技术综述[J]. 石油知识, 2019(2): 42-43. (Wang Yike. Overview of shale gas exploration and development technology[J]. Petroleum Knowledge, 2019 (2): 42-43. (in Chinese))
[3]曾义金, 周俊, 王海涛, 等. 深层页岩真三轴变排量水力压裂物理模拟研究[J]. 岩石力学与工程学报, 2019,38(9): 1758-1766. (Zeng Yijin, Zhou Jun, Wang Haitao, et al. Physical simulation of true triaxial variable displacement hydraulic fracturing for deep shale. [J]. Chinese Journal of Rock Mechanics and Engineering, 2019,38 (9): 1758-1766. (in Chinese))
[4]考佳玮, 金衍, 付卫能, 等. 注液方式对深层页岩裂缝形态影响实验研究[J]. 地下空间与工程学报, 2019,15(1): 32-38. (Kao Jiawei, Jin Yan, Fu Weineng, et al. Experimental study on the effect of fluid injection mode on deep shale fracture morphology[J]. Journal of Underground Space and Engineering, 2019, 15(1): 32-38. (in Chinese))
[5]申峰, 任相彦, 周雷, 等. 储层非均质性对水力压裂裂缝扩展的影响研究[J]. 地下空间与工程学报, 2021,17(5): 1444-1456. (Shen Feng, Ren Xiangyan, Zhou Lei, et al. Study on the effect of reservoir heterogeneity on fracture propagation of hydraulic fracturing[J] Journal of Underground Space and Engineering, 2021,17(5): 1444-1456. (in Chinese))
[6]Liu Q L,, Tian S C, Li G S, et al. An analytical model for fracture initiation from radial lateral borehole[J]. Journal of Petroleum Science and Engineering, 2018,164: 206-218.
[7]周雷, 李立, 夏彬伟, 等. 含径向水力割缝钻孔导向压裂裂缝形态及影响要素[J]. 煤炭学报, 2022, 47(4): 1559-1570. (Zhou Lei, Li Li, Xia Binwei, et al. Fracture shape and influencing factors of guided fracturing in borehole with radial hydraulic slotting[J]. Journal of Coal, 2022,47 (4): 1559-1570. (in Chinese))
[8]Zhang H, Chen J, Zhao Z, et al. Hydraulic fracture network propagation in a naturally fractured shale reservoir based on the“well factory”model[J]. Computers and Geotechnics, 2023,153: 105103.
[9]于斌, 高瑞, 夏彬伟, 等. 大空间坚硬顶板地面压裂技术与应用[J]. 煤炭学报. 2021, 46(3): 800-811. (Yu Bin, Gao Rui, Xia Binwei, et al. Surface fracturing technology with large space and hard roof and its application[J]. Journal of Coal, 2021,46 (3): 800-811. (in Chinese))
[10]王海洋, 周宴民, 孙凯, 等. 水平裂缝对坚硬顶板失稳破断的影响规律研究[J]. 中国煤炭, 2020, 46(4): 77-82. (Wang Haiyang, Zhou Yanmin, Sun Kai, et al. Study on the influence of horizontal cracks on the instability and fracture of hard roof[J]. China Coal, 2020, 46 (4): 77-82. (in Chinese))
[11]Chen L, Chen W, Chen Y, et al. Investigation of hydraulic fracture propagation using a post-peak control system coupled with acoustic emission[J]. Rock Mechanics and Rock Engineering, 2015,48(3): 1233-1248.
[12]杨红伟, 许江, 聂闻, 等. 单轴压缩砂岩水力压裂力学特性试验研究[J]. 重庆大学学报, 2016,39(5): 90-96. (Yang Hongwei, Xu Jiang, Nie Wen, et al. Experimental study on mechanical properties of hydraulic fracturing of sandstone under uniaxial compression[J]. Journal of Chongqing University, 2016,39 (5): 90-96. (in Chinese))
[13]宁文祥, 何柏, 李凤霞, 等. 陆相页岩油储层水力压裂裂缝形态的试验[J]. 科学技术与工程, 2021,21(18): 7505-7512. (Ning Wenxiang, He Bai, Li Fengxia, et al. Experimental study on fracture morphology of hydraulic fracturing in continental shale oil reservoir[J]. Science Technology and Engineering, 2021, 21(18): 7505-7512. (in Chinese))
[14]何强, 李凤霞, 史爱萍, 等. 基于三维CT重构的油页岩复杂水力裂缝网络分形表征[J]. 油气地质与采收率, 2021, 28(5): 116-123. (He Qiang, Li Fengxia, Shi Aiping, et al. Fractal characterization of complex hydraulic fracture network in oil shale based on 3D CT reconstruction[J]. Oil and Gas Geology and Recovery, 2021,28 (5): 116-123. (in Chinese))
[15]冯彦军, 康红普. 水力压裂起裂与扩展分析[J]. 岩石力学与工程学报, 2013,32(增2): 3169-3179. (Feng Yanjun, Kang Hongpu. Analysis of hydraulic fracturing initiation and propagation[J]. Chinese Journal of Rock Mechanics and Engineering, 2013,32 (Supp.2): 3169-3179. (in Chinese))
[16]Gramberg J. The ellipse-with-notch, theory to explain axial cleavage fracturing of rocks (a natural extension to first griffith theory) [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts,1970,7(5):537-559.
[17]马新仿, 李宁, 尹丛彬, 等. 页岩水力裂缝扩展形态与声发射解释——以四川盆地志留系龙马溪组页岩为例[J]. 石油勘探与开发, 2017,44(6): 974-981. (Ma Xinfang, Li Ning, Yin Congbin, et al. Hydraulic fracture propagation pattern of shale and acoustic emission interpretation: a case study of Silurian Longmaxi Formation shale in Sichuan Basin[J]. Petroleum Exploration and Production, 2017,44 (6): 974-981. (in Chinese))
