Study on Seepage Mechanism Characteristics of A Single Fracture Based on Fracture Deformation Under Different Confining Pressures

doi:10.19657/j.geoscience.1000-8527.2023.059

Abstract

Abstract:

It is necessary to study the seepage flow under different confining pressures in laboratory because the real groundwater flow and solute transport are affected by the extensive and complex distribution of in-situ stress. In practical projects such as groundwater pollution prevention and control, the permeability of fractures is signi-ficantly affected by confining pressure. Based on the basic constitutive law, the seepage flow under confining pressure is analyzed quantitatively in this paper. Based on the deformation of hydraulic aperture and the defor-mation law of fracture, the relationship model between seepage characteristics (seepage pressure P_s, hydraulic aperture e_h and permeability k) and confining pressure P_c under confining pressure is established. The hydraulic experiment of a single fracture of marble is carried out in a core holder, and the experimental data are regressed. It is verified that the model has a high fitting effect. It can effectively predict the relationship between the seepage characteristics (seepage pressure, hydraulic opening and permeability) and the surrounding pressure.

Key words: confining pressure, fracture deformation constitutive law, single fracture, hydraulic aperture, permeability

CLC Number:

P641.2
TU452

CHENG Zhiyu, LIU Rui, ZHANG Jinfeng, MA Haichun, WANG Jingping. Study on Seepage Mechanism Characteristics of A Single Fracture Based on Fracture Deformation Under Different Confining Pressures[J]. Geoscience, 2023, 37(04): 972-976.

Figures/Tables 8

Fig.1 Conceptual model of change between hydraulic aperture eh and confining pressure Pc

Fig.2 Hydro-mechanical test system of this study

Fig.3 Preparation of cylindrical fractured marble sample of this study

Fig.4 Relationship between confining pressure and seepage pressure under the constant flow rate

Table 1 Regression analysis of Pc and Ps

流量Q (mL/min)	$e h i$	f_cU_m	K_n	$12 μ l Q w$	R²
0.2	1.13	0.77	5.72	493.06	0.9897
0.3	1.15	0.78	5.83	755.62	0.9918
0.4	1.17	0.79	5.94	1058.86	0.9895
0.5	1.19	0.8	6.02	1363.62	0.9939

Table 1 Regression analysis of Pc and Ps

流量Q (mL/min)	$e h i$	f_cU_m	K_n	$12 μ l Q w$	R²
0.2	1.13	0.77	5.72	493.06	0.9897
0.3	1.15	0.78	5.83	755.62	0.9918
0.4	1.17	0.79	5.94	1058.86	0.9895
0.5	1.19	0.8	6.02	1363.62	0.9939

Fig.5 Relationship between confining pressure and hydraulic opening under fixed flow conditions

Fig.6 Relationship between confining pressure and permeabi-lity under fixed flow conditions

Table 2 Regression analysis of Pc and eh or Pc and k

参数	流量Q (mL/min)	R²
e_h	0.2	0.9913
	0.3	0.9906
	0.4	0.9892
	0.5	0.9886
k	0.2	0.9865
	0.3	0.9927
	0.4	0.9956
	0.5	0.9846

References 13

[1]	苟波, 郭建春. 页岩水平井体积压裂设计的一种新方法[J]. 现代地质, 2013, 27(1):217 - 222.
[2]	米博, 项彦勇. 砂土地层浅埋盾构隧道开挖渗流稳定性的模型试验和计算研究[J]. 岩土力学, 2020, 41(3):837-848.
[3]	赵志宏, 刘桂宏, 谭现锋, 等. 基于等效渗流通道模型的地热尾水回灌理论模型[J]. 水文地质工程地质, 2017, 44(3):158-164.
[4]	谈云志, 彭帆, 钱芳红, 等. 石墨-膨润土缓冲材料的最优配置方法[J]. 岩土力学, 2019, 40(9):3387-3396.
[5]	ZIMMERMAN R W, BODVARSSON G S. Hydraulic conductivity of rock fractures[J]. Transport in Porous Media, 1996, 23(1): 1-30.
[6]	ZIMMERMAN R W, YEO I W. Fluid flow in rock fractures: From the Navier-Stokes equations to the cubic law[J]. Geophysical Monograph-American Geophysical Union, 2000, 122: 213-224.
[7]	WITHERSPOON P A, WANG J S Y, IWAI K, et al. Validity of cubic law for fluid flow in a deformable rock fracture[J]. Water Resources Research, 1980, 16(6): 1016-1024. DOI URL
[8]	MA D, MIAO X X, CHEN Z Q, et al. Experimental investigation of seepage properties of fractured rocks under different confining pressures[J]. Rock Mechanics and Rock Engineering, 2013, 46 (5): 1135-1144. DOI URL
[9]	杨金保, 冯夏庭, 潘鹏志. 考虑应力历史的岩石单裂隙渗流特性试验研究[J]. 岩土力学, 2013, 34(6):1629-1635.
[10]	WANG J, MA H, FENG P, et al. An experimental study on seepage within shale fractures due to confining pressure and temperature[J]. KSCE Journal of Civil Engineering, 2021, 25: 3596-3604. DOI
[11]	FIDELIBUS C. The 2D hydro-mechanically coupled response of a rock mass with fractures via a mixed BEM—FEM technique[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2007, 31 (11): 1329-1348. DOI URL
[12]	孙广忠, 林文祝. 结构面闭合变形法则及岩体弹性变形本构方程[J]. 地质科学, 1983, 18(2):177-180.
[13]	WANG J, MA H, QIAN J, et al. Experimental and theoretical study on the seepage mechanism characteristics coupling with confining pressure[J]. Engineering Geology, 2021, 291:106224. DOI URL

[1]	WEI Yongheng, GE Yanyan, WANG Gang, WANG Wenfeng, TIAN Jijun, LI Xin, WU Bin, ZHANG Xiao. In-situ Stress Distribution and Its Influence on Coalbed Methane Development in Tielieke Mining Area, Kubai Coalfield, Xinjiang [J]. Geoscience, 2022, 36(05): 1324-1332.
[2]	LI Jinlong, LI Qian, CAI Yidong, CHEN Wei, CHEN Zhizhu, WANG Jian, XUE Xiaohui. Geological Conditions and Resource Potential of Coalbed Methane Reservoirs in Laochang Mining Area, Yunnan Province [J]. Geoscience, 2022, 36(05): 1351-1359.
[3]	LIU Xiaotong, XUAN Lingling, ZHU Chunyan, ZHAO Ying, GUO Chang, LI Song, ZHANG Hao, SHI Zhenyun, LUO Wanjing. Dynamic Evaluation of High-capacity Channel in Heavy Oil Reservoirs with Medium-high Permeability [J]. Geoscience, 2021, 35(02): 388-395.
[4]	GUO Qi, LI Zhen, LI Ping. Horizontal Well Potential Digging Technology of Point-bar Sandbody in Ultra-high Water Cut Stage: Evaluation of Flow Field Intensity [J]. Geoscience, 2021, 35(02): 396-402.
[5]	WANG Lei, GUO Changbao, LI Bin, HUANG Xin, ZHENG Zhihua, WANG Jiaqi. Experimental Study on Influence of Confining Pressure and Water Content on Dynamic Strength of Slate Residual Soil [J]. Geoscience, 2021, 35(01): 161-166.
[6]	WANG Meng, LIU Zhijie, YANG Yuqing, ZHANG Zhiqiang, LIU Haibo, DONG Yu. Comprehensive Classification Scheme of Huagang Reservoir in Xihu Depression [J]. Geoscience, 2020, 34(06): 1214-1220.
[7]	MA Fengchun, LIU Jincheng, WU Yanxiong, LIANG Xiaoyu, JIANG Yinghai, WANG Lin, ZHOU Yan, XIANG Yiwei. Calculation and Evaluation Method of Reservoir Parameters in Multiple Oil Reservoirs Based on Flow Unit [J]. Geoscience, 2020, 34(02): 370-377.
[8]	LI Ming, ZHU Yushuang, LI Wenhong, YUAN Guowei, DU Chaofeng. Feasibility Study on Applying CO₂-flooding Micro-visualization Technology in Ultra-low Permeability Reservoirs: A Case Study in Ordos Basin [J]. Geoscience, 2019, 33(04): 911-918.
[9]	LI Shanshan, PENG Song, CHEN Lin, LI Shengyong, LI Lianyi, LIU Xiaoyan. A Review on the Complex Reservoir Sedimentary Characteristics and Low Permeability Formation of the Upper Eocene to Lower Oligocene in the Wenchang B Sag, Pearl River Estuary Basin [J]. Geoscience, 2019, 33(02): 357-369.
[10]	LIU Na, KANG Yongshang, LI Zhe, WANG Jin, SUN Liangzhong, JIANG Shanyu. Geological Controlling Factors of Coal Pore System and Its Significance in CBM Development [J]. Geoscience, 2018, 32(05): 963-974.
[11]	WANG Fushun, LIU Pengcheng, WANG Wenhuan, HAO Mingqiang, ZHUANG Yongtao. Optimization Study of Fracturing Length for Rhombus Inverse Nine-spot Diamond Reverse Well Pattern in Anisotropy Reservoirs [J]. Geoscience, 2018, 32(03): 547-553.
[12]	CUI Chuanzhi, CHEN Honglin, GUO Yingchun, WANG Qian, ZHANG Shufan. Reasonable Water-injecting Development Methods of Multiple-fracturing Horizontal Well in Ultra-Low Permeability Glutenite Reservoir [J]. Geoscience, 2018, 32(01): 198-204.
[13]	XU Zhenhua, LIU Pengcheng, WANG Wenhuan, XIA Jing, HAO Mingqiang, PENG Huanhuan. Optimization Study of Unequal Fracturing Length for Rhombus Inverse Nine-spot Well Pattern in Low Permeability Reservoir [J]. Geoscience, 2017, 31(03): 606-613.
[14]	YU Qingyan, LIU Pengcheng, LI Yong, XIA Jing, HAO Mingqiang, LI Baozhu. Research of Mathematical Model and Influencing Factors of Water Invasion Performance for Horizontal Well in Fractured-vuggy Gas Reservoirs with Bottom Water [J]. Geoscience, 2017, 31(03): 614-622.
[15]	WANG Mingxian, FAN Zifei, LUO Wanjing, DING Jie, TIAN Qing, YAO Min，BU Xia. Feasibility Analysis of Water Flooding with Multifractured Horizontal Wells in Ultralow Permeability Reservoirs [J]. Geoscience, 2016, 30(6): 1361-1369.