The emission of infrared radiation from oil shale is, compared with other rocks, more intense due to the anisotropy during deformation. In this research, cracks in oil shale specimens were scanned with computed tomography (CT) scanning equipment, and the infrared radiation from their surface, as well as surface strain during uniaxial compression were analyzed. The results show that the specimens surface temperature constantly changes. Prior to the fluctuation of the internal stress of a test specimen, the temperature curve exhibits varying degrees of decline. Then the curve abruptly rises close to the specimen’s point of failure. By analyzing the coefficient of variation of the surface temperature distribution of the specimens, it was found that the turning point on the curve from the horizontal fluctuation to rapid increase can serve as a warning of impending specimen failure. In a low-stress state, the location of a crack is indicative of the low-temperature infrared anomaly. With increasing stress, the high-temperature infrared anomaly will appear at the crack tip. Near the failure of the specimen, the appearance of an anomalous infrared precursor on its surface is related to the mode of failure. A high-temperature infrared precursor will occur in a shear failure zone, while a low-temperature infrared precursor will occur in a tensile zone. These regularities are very important to be taken into account to understand the development of the internal fracture network and deformation of oil shale deposits during in-situ pyrolysis.
1. Scales, J. A., Batzle, M. Millimeter wave analysis of the dielectric properties of oil shales. Appl. Phys. Lett., 2006, 89(2), 024102.
https://doi.org/10.1063/1.2219720
2. Du, J., Hu, L., Meegoda, J. N., Zhang, G. Shale softening: Observations, phenomenological behavior, and mechanisms. Appl. Clay Sci., 2018, 161, 290‒300.
https://doi.org/10.1016/j.clay.2018.04.033
3. Zhu, P., Balhoff, M. T., Mohanty, K. K. Compositional modeling of fracture-to-fracture miscible gas injection in an oil-rich shale. J. Petrol. Sci. Eng., 2017, 152, 628‒638.
https://doi.org/10.1016/j.petrol.2017.01.031
4. Brandt, A. R., Millard-Ball, A., Ganser, M., Gorelick, S. M. Peak oil demand: the role of fuel efficiency and alternative fuels in a global oil production decline. Environ. Sci. Technol., 2013, 47(14), 8031‒8041.
https://doi.org/10.1021/es401419t
5. Jiang, X. M., Han, X. X, Cui, Z. G. New technology for the comprehensive utilization of Chinese oil shale resources. Energy, 2007, 32(5), 772‒777.
https://doi.org/10.1016/j.energy.2006.05.001
6. Kang, Z. Q., Zhao, Y. S., Yang, D. Physical principle and numerical analysis of oil shale development using in-situ conversion process technology. Acta Petrol. Sin., 2008, 29(4), 592‒595.
7. Masoudian, M. S., Hashemi, M. A., Tasalloti, A., Marshall, A. M. Elastic-brittle-plastic behaviour of shale reservoirs and its implications on fracture permeability variation: an analytical approach. Rock Mech. Rock Eng., 2018, 51(5), 1565‒1582.
https://doi.org/10.1007/s00603-017-1392-y
8. Vik, H. S., Salimzadeh, S., Nick, H. M. Heat recovery from multiple-fracture enhanced geothermal systems: the effect of thermoelastic fracture interactions. Renew. Energ., 2018, 121, 606‒622.
https://doi.org/10.1016/j.renene.2018.01.039
9. Luo, Y., Xie, H. P., Ren, L., Zhang, R., Li, C. B., Gao, C. Linear elastic fracture mechanics characterization of an anisotropic shale. Sci. Rep., 2018, 8(1), 8505.
https://doi.org/10.1038/s41598-018-26846-y
10. Miao, X., Guan, L., Bao, R., Li, Y., Zhan, H., Zhao, K., Xu, F. Layer caused an anisotropic terahertz response of a 3D-printed simulative shale core. Anal. Sci., 2017, 33(12), 1327‒1331.
https://doi.org/10.2116/analsci.33.1327
11. Rahmati, E., Nouri, A., Fattahpour, V., Trivedi, J. J. Numerical assessment of the maximum operating pressure for SAGD projects by considering the intrinsic shale anisotropy. J. Petrol. Sci. Eng., 2017, 148, 10‒20.
https://doi.org/10.1016/j.petrol.2016.09.036
12. Wang, M., Li, P., Wu, X., Chen, H. A study on the brittleness and progressive failure process of anisotropic shale. Environ. Earth Sci., 2016, 75(10), 886.
https://doi.org/10.1007/s12665-016-5700-8
13. Minaeian, V., Dewhurst, D. N., Rasouli, V. Deformational behaviour of a clay-rich shale with variable water saturation under true triaxial stress conditions. Geomech. Energy Environ., 2017, 11, 1‒13.
https://doi.org/10.1016/j.gete.2017.04.001
14. Cheshomi, A., Hajipour, G., Hassanpour, J., Dashtaki, B. B., Firouzei, Y., Sheshde, E. A. Estimation of uniaxial compressive strength of shale using indentation testing. J. Petrol. Sci. Eng., 2017, 151, 24‒30.
https://doi.org/10.1016/j.petrol.2017.01.030
15. Minardi, A., Ferrari, A., Ewy, R., Laloui, L. Nonlinear elastic response of partially saturated gas shales in uniaxial compression. Rock Mech. Rock Eng., 2018, 51, 1967‒1978.
https://doi.org/10.1007/s00603-018-1453-x
16. Zhou, M., Zhang, Y., Zhou, R., Hao, J., Yang, J. Mechanical property measurements and fracture propagation analysis of Longmaxi shale by micro-CT uniaxial compression. Energies, 2018, 11(6), 1409.
https://doi.org/10.3390/en11061409
17. Yan, C., Deng, J., Hu, L., Chen, Z., Yan, X., Lin, H., Tan, Q., Yu, B. Brittle failure of shale under uniaxial compression. Arab. J. Geosci., 2015, 8(5), 2467‒2475.
https://doi.org/10.1007/s12517-014-1373-3
18. Shi, X., Liu, D. A., Yao, W., Shi, Y., Tang, T., Wang, B., Han, W. Investigation of the anisotropy of black shale in dynamic tensile strength. Arab. J. Geosci., 2018, 11(2), 42.
https://doi.org/10.1007/s12517-018-3384-y
19. Wu, L., Liu, S., Wu, Y., Wang, C. Precursors for rock fracturing and failure ‒ Part I: IRR image abnormalities. Int. J. Rock Mech. Min. Sci., 2006, 43(3), 473‒482.
https://doi.org/10.1016/j.ijrmms.2005.09.002
20. Qi, K., Tan, Z. Experimental study on acoustoelastic character of rock under uniaxial compression. Geotech. Geol. Eng., 2018, 36(1), 247‒256.
https://doi.org/10.1007/s10706-017-0323-8
21. Ma, L., Sun, H., Zhang, Y., Zhou, T., Li, K., Guo, J. Characteristics of infrared radiation of coal specimens under uniaxial loading. Rock Mech. Rock Eng., 2016, 49(4), 1567‒1572.
https://doi.org/10.1007/s00603-015-0780-4
22. Wang, C., Lu, Z., Liu, L., Chuai, X., Lu, H. Predicting points of the infrared precursor for limestone failure under uniaxial compression. Int. J. Rock Mech. Min. Sci., 2016, 88(10), 34‒43.
https://doi.org/10.1016/j.ijrmms.2016.07.004
23. Zhao, Y., Jiang, Y. Acoustic emission and thermal infrared precursors associated with bump-prone coal failure. Int. J. Coal Geol., 2010, 83(1), 11‒20.
https://doi.org/10.1016/j.coal.2010.04.001
24. Wu, L., Liu, S., Wu, Y., Wu, H. Changes in infrared radiation with rock deformation. Int. J. Rock Mech. Min. Sci., 2002, 39(6), 825‒831.
https://doi.org/10.1016/S1365-1609(02)00049-7
25. Wu, L., Liu, S., Wu, Y., Wang, C. Precursors for rock fracturing and failure ‒ Part II: IRR T-curve abnormalities. Int. J. Rock Mech. Min. Sci., 2006, 43(3), 483‒493.
https://doi.org/10.1016/j.ijrmms.2005.09.001
26. Wang, X. J. A research on the inorganic carbon dioxide from rock by thermal simulation experiments. Advances in Earth Science, 2003, 18(4), 515–520 (in Chinese).
27. Li, Y.-X., Liu, J.-F. Study on deformation characteristic of surrounding rock by R/S method and fractal theory. Journal of Sichuan University (Engineering Science Edition), 2010, 42(3), 43‒48 (in Chinese).
28. Sun, X., Xu, H., He, M., Zhang, F. Experimental investigation of the occurrence of rockburst in a rock specimen through infrared thermography and acoustic emission. Int. J. Rock Mech. Min. Sci., 2017, 93, 250‒259.
https://doi.org/10.1016/j.ijrmms.2017.02.005
29. Liu, S., Wu, L., Wu, Y. Infrared radiation of rock at failure. Int. J. Rock Mech. Min. Sci., 2006, 43(6), 972‒979.
https://doi.org/10.1016/j.ijrmms.2005.12.009
30. Kivi, I. R., Ameri, M., Molladavoodi, H. An experimental investigation on deformation and failure behavior of carbonaceous Garau shale in Lurestan Basin, west Iran: Application in shale gas development. J. Nat. Gas Sci. Eng., 2018, 55, 135‒153.
https://doi.org/10.1016/j.jngse.2018.04.028
31. Liu, L. Q., Chen, G. Q., Liu, P. X., Chen, S. Y., Ma, J. Infrared measurement system for rock deformation experiment. Seismology & Geology, 2004, 26(3), 492‒501 (in Chinese).
32. Eberhardt, E., Stead, D., Stimpson, B., Read, R. S. Identifying crack initiation and propagation thresholds in brittle rock. Can. Geotech. J., 1998, 35(2), 222‒233..
https://doi.org/10.1139/t97-091
