Current Science

Open Access Open Access  Restricted Access Subscription Access

Effects of Bedding on Hydraulic Fracturing in Coalbed Methane Reservoirs


Affiliations
1 Hubei Province Key Laboratory of Processing of Mineral Resources and Environment, School of Resource and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China
 

Bedding is a special structure of coal, which has notable effects on the mechanical parameters of coal and on the hydraulic fracture propagating in coal bed methane reservoirs. To study the effects of bedding onanisotropic characteristics of coal fracture toughness,three-point bending tests have been carried out on raw coal specimens. The results indicate that fracture toughness and failure modes of the specimens both have strong anisotropy due to bedding. A geological geomechanical model of a coal bed methane (CBM)reservoir is built taking into account the effect of bedding to study the hydraulic fracture propagation and the influence of bedding on the fracture network. The hydraulic fracture initiates at the end of the perforation and tends to bifurcate and swerve at the bedding to produce induced fractures. Ultimately, these fractures form a complicated fracture network. The fracture toughness of bedding has great influence on hydraulic fracture geometry. The fracture is likely to bifurcate and swerve at the bedding to form multiple secondary fractures with larger bedding fracture toughness.

Keywords

Coalbed Methane, Coal Seam, Fracture Toughness, Hydraulic Fracturing, Numerical Simulation, Three Point Bending Test.
User
Notifications
Font Size

  • Han, F. S., Busch, A., Krooss, B. M., Liu, Z. Y., Wageningen, N. V. and Yang, J. L., Experimental study on fluid transport processes in the cleat and matrix systems of coal. Energ. Fuel., 2010, 24, 6653–6661.

  • Pan, R. K., Cheng, Y. P., Yuan, L., Yu, M. G. and Dong, J., Effect of bedding structural diversity of coal on permeability evolution and gas disasters control with coal mining. Nat. Hazards, 2014, 73(2), 531–546.

  • Claesson, J. and Bohloli, B., Brazilian test: stress field and tensile strength of anisotropic rocks using an analytical solution. Int. J. Rock Mech. Min. Sci., 2002, 39, 991–1004.

  • Zhang, Z. T., Zhang, R., Li, G., Li, H. G. and Liu, J. F., The effect of bedding structure on mechanical property of coal. Adv. Mater. Sci. Eng., 2014, 2014, 1–7.

  • Grasselli, G., Lisjak, A., Mahabadi, O. K. and Tatone, B. S. A., Influence of pre-existing discontinuities and bedding planes on hydraulic fracturing initiation. Eur. J. Environ. Civ. Eng., 2015, 19(5), 580–597.

  • Li, Z. et al., Propagation of hydraulic fissures and bedding planes in hydraulic fracturing of shale. Chin. J. Rock Mech. Eng., 2015, 34(1), 12–20.

  • Jeffrey, R. G., Weber, C. R., Vlahovic, W. and Enever, J. R., Hydraulic fracturing experiments in the great northern coal seam. In SPE Asia Pacific Oil and Gas Conference, Melbourne, Australian, 7–10 November 1994.

  • Gu, H., Siebrits, E. and Sabourov, A., Hydraulic-fracture modeling with bedding plane interfacial slip. In SPE Eastern Regional/ AAPG Eastern Section Joint Meeting, Pittsburgh, PA, United States, 11–15 October 2008.

  • Cho, J. W., Kim, H., Jeon, S. and Min, K. B., Deformation and strength anisotropy of Asan gneiss, Boryeong shale, and Yeoncheon schist. Int. J. Rock Mech. Min. Sci., 2012, 50, 158–169.

  • Liu, K. D., Liu, Q. S., Zhu, Y. G. and Liu, B., Experimental study of coal considering directivity effect of bedding plane under Brazilian splitting and uniaxial compression. Chin. J. Rock Mech. Eng., 2013, 32(2), 308–316.

  • Guo, T. K., Zhang, S. C., Qu, Z. Q., Zhou, T., Xiao, Y. S. and Gao, J., Experimental study of hydraulic fracturing for shale by stimulated reservoir volume. Fuel, 2014, 128, 373–380.

  • Heng, S., Guo, Y. T., Yang, C. H., Daemen, J. J. K. and Li, Z., Experimental and theoretical study of the anisotropic properties of shale. Int. J. Rock Mech. Min. Sci., 2015, 74, 58–68.

  • Jiang, T. T., Zhang, J. H. and Wu, H., Experimental and numerical study on hydraulic fracture propagation in coalbed methane reservoir. J. Nat. Gas Sci. Eng., 2016, 35, 455–467.

  • Ma, Y., Pan, Z. J., Zhong, N. N., Connell, L. D., Down, D. I., Lin, W. L. and Zhang, Y., Experimental study of anisotropic gas permeability and its relationship with fracture structure of Longmaxi Shales, Sichuan Basin, China. Fuel, 2016, 180, 106–115.

  • Zou, Y. S., Ma, X. F., Zhang, S. C., Zhou, T. and Li, H., Numerical investigation into the influence of bedding plane on hydraulic fracture network propagation in shale formations. Rock Mech. Rock Eng., 2016, 49, 3597–3614.

  • Tang, C. A. and Hudson, J. A., Rock Failure Mechanisms Explained and Illustrated, CRC Press, 2010.

  • Fakhimi, A. and Wan, F., Discrete element modeling if the process zone shape in mode I fracture at peak load and in post-peak regime. Int. J. Rock Mech. Min. Sci., 2016, 85, 119–128.

  • Googarchin, H. S. and Ghajar, R., Stress intensity factors calculation for surface crack in cylinders under longitudinal gradient pressure using general point load weight function. Fatigue Fract. Eng. M., 2014, 37(2), 184–194.

  • Heng, S., Yang, C. H., Guo, Y. T., Wang, C. Y. and Wang, L., Influence of bedding planes on hydraulic fracture propagation in shale formations. Chin. J. Rock Mech. Eng., 2015, 34(2), 228–237.

  • Sih, G. C., Pairs, P. C. and Irwin, G. R., On cracks in rectilinearly anisotropic bodies. Int. J. Fract. Mech., 1965, 1(3), 189–203.

  • Dai, F. and Xia, K. W., Laboratory measurements of the rate dependence of the fracture toughness anisotropy of Barre granite. Int. J. Rock Mech. Min. Sci., 2013, 60, 57–65.

  • Ministry of Water Resources of the People’s Republic of China, Specifications for Rock Tests in Water Conservancy and Hydroelectric Engineering, China Standards Press, Beijing, 2007.

  • Chong, K. P., Kuruppu, M. D. and Kuszmaul, J. S., Fracture toughness determination of layered materials. Eng. Fract. Mech., 1987, 28(1), 43–54.


Abstract Views: 333

PDF Views: 123




  • Effects of Bedding on Hydraulic Fracturing in Coalbed Methane Reservoirs

Abstract Views: 333  |  PDF Views: 123

Authors

Tingting Jiang
Hubei Province Key Laboratory of Processing of Mineral Resources and Environment, School of Resource and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China
Jianhua Zhang
Hubei Province Key Laboratory of Processing of Mineral Resources and Environment, School of Resource and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China
Gang Huang
Hubei Province Key Laboratory of Processing of Mineral Resources and Environment, School of Resource and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China
Shaoxian Song
Hubei Province Key Laboratory of Processing of Mineral Resources and Environment, School of Resource and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China
Hao Wu
Hubei Province Key Laboratory of Processing of Mineral Resources and Environment, School of Resource and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, Hubei, China

Abstract


Bedding is a special structure of coal, which has notable effects on the mechanical parameters of coal and on the hydraulic fracture propagating in coal bed methane reservoirs. To study the effects of bedding onanisotropic characteristics of coal fracture toughness,three-point bending tests have been carried out on raw coal specimens. The results indicate that fracture toughness and failure modes of the specimens both have strong anisotropy due to bedding. A geological geomechanical model of a coal bed methane (CBM)reservoir is built taking into account the effect of bedding to study the hydraulic fracture propagation and the influence of bedding on the fracture network. The hydraulic fracture initiates at the end of the perforation and tends to bifurcate and swerve at the bedding to produce induced fractures. Ultimately, these fractures form a complicated fracture network. The fracture toughness of bedding has great influence on hydraulic fracture geometry. The fracture is likely to bifurcate and swerve at the bedding to form multiple secondary fractures with larger bedding fracture toughness.

Keywords


Coalbed Methane, Coal Seam, Fracture Toughness, Hydraulic Fracturing, Numerical Simulation, Three Point Bending Test.

References





DOI: https://doi.org/10.18520/cs%2Fv113%2Fi06%2F1153-1159