Abstract
Most of the rock salt of China is bedded, in which non-salt layers and rock salt layers alternate. Due to the poor solubility of the non-salt layers, many blocks overhang on the walls of the caverns used for gas storage, constructed by water leaching. These overhanging blocks may collapse at any time, which may damage the tubing and casing string, and even cause instability of the cavern. They are one of the main factors threatening the safety of caverns excavated in bedded rock salt formations. In this paper, a geomechanical model of the JJKK-D salt cavern, located in Jintan salt district, Jintan city, Jiangsu province, China, is established to evaluate the stability of the overhanging blocks on its walls. The characters of the target formation, property parameters of the rock mass, and actual working conditions are considered in the geomechanical model. An index system composed of stress, displacement, plastic zone, safety factor, and equivalent strain is used to predict the collapse length of the overhanging blocks, the moment the collapse will take place, and the main factors causing the collapse. The sonar survey data of the JJKK-D salt cavern are used to verify the reliability and accuracy of the proposed geomechanical model. The results show that the proposed geomechanical model has a good reliability and accuracy, and can be used for the collapse prediction of the overhanging blocks on the wall of the JJKK-D salt cavern. The collapse length of the overhanging block is about 8 m. We conclude that the collapse takes place during the debrining. The reason behind the collapse is the sudden decrease of the fluid density, leading to the increase of the self-weight of the overhanging blocks. This study provides a basis for the collapse prediction method of the overhanging blocks of Jintan salt cavern gas storage, and can also serve as a reference for salt cavern gas storage with similar conditions to deal with overhanging blocks.
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Abbreviations
- A :
-
Material constant
- I 1 :
-
First invariant of the stress tensor, I 1 = σ 1 + σ 2 + σ 3
- J 2 :
-
Second invariant of the deviatoric stress tensor, \(J_{2} = \frac{1}{6}\left[ {\left( {\sigma_{1} - \sigma_{2} } \right)^{2} + \left( {\sigma_{2} - \sigma_{3} } \right)^{2} + \left( {\sigma_{3} - \sigma_{1} } \right)^{2} } \right]\)
- SFvs :
-
Safety factor for dilatancy
- n :
-
Stress index, and is usually valued as 3–6 for rock salt
- \(\overline{\sigma }\) :
-
Deviatoric stress, \(\overline{\sigma } = \sigma_1-\sigma_3\)
- σ 1 :
-
Maximum principal stress
- σ 2 :
-
Intermediate principal stress
- σ 3 :
-
Minimum principal stress
- \(\dot{\varepsilon }\) :
-
Steady-state creep rate
- ε dev :
-
Deviatoric strain tensor
- ε eq :
-
Equivalent strain
References
ANSYS Inc. (2012) ANSYS 14.5 mechanical APDL verification manual. Canonsburg, Pennsylvania, USA. Home page at: http://www.ansys.com
Bérest P (2013) The mechanical behavior of salt and salt caverns. In: Proceedings of the ISRM International Symposium EUROCK 2013, Wroclaw, Poland, 23–26 October 2013. ISRM-EUROCK-2013-002. International Society for Rock Mechanics, pp 17–30
Bérest P, Bergues J, Brouard B, Durup JG, Guerber B (2001) A salt cavern abandonment test. Int J Rock Mech Min Sci 38(3):357–368
Deng JQ, Yang Q, Liu YR, Pan YW (2015) Stability evaluation and failure analysis of rock salt gas storage caverns based on deformation reinforcement theory. Comput Geotech 68:147–160
Djizanne H, Bérest P, Brouard B (2014) The mechanical stability of a salt cavern used for compressed air energy storage (CAES). In: Proceedings of the 2014 Spring SMRI Technical Conference, San Antonio, Texas, USA, 4–7 May 2014
Guo YT, Yang CH, Mao HJ (2012) Mechanical properties of Jintan mine rock salt under complex stress paths. Int J Rock Mech Min Sci 56:54–61
Han G, Bruno MS, Lao K, Young J, Dorfmann L (2007) Gas storage and operations in single-bedded salt caverns: stability analyses. SPE Prod Oper 22(03):368–376
Heusermann S, Rolfs O, Schmidt U (2003) Nonlinear finite-element analysis of solution mined storage caverns in rock salt using the LUBBY2 constitutive model. Comput Struct 81(8):629–638
Im S, Atluri SN (1987) A study of two finite strain plasticity models: an internal time theory using Mandel’s director concept, and a general isotropic/kinematic-hardening theory. Int J Plast 3:163–191
Itasca Consulting Group Inc. (2005) FLAC3D version 3.0 users’ manual. Itasca Consulting Group, Inc., New York, USA
Langer M, Heusermann S (2001) Geomechanical stability and integrity of waste disposal mines in salt structures. Eng Geol 61(2–3):155–161
Li YP, Liu W, Yang CH, Daemen JJK (2014) Experimental investigation of mechanical behavior of bedded rock salt containing inclined interlayer. Int J Rock Mech Min Sci 69:39–49
Sobolik SR, Ehgartner BL (2006) Analysis of cavern shapes for the strategic petroleum reserve. No. SAND2006-3002. Sandia National Laboratories, Albuquerue, NM, USA
Staudtmeister K, Rokahr RB (1997) Rock mechanical design of storage caverns for natural gas in rock salt mass. Int J Rock Mech Min Sci 34:300.e1–300.e13
Swift GM, Reddish DJ (2005) Underground excavations in rock salt. Geotechn Geol Eng 23:17–42
Tecplot Inc. (2013) Tecplot 360 user’s manual. Tecplot Inc., Bellevue, Washington, USA. Available online at: https://www.scc.kit.edu/downloads/sca/tpum.pdf. Accessed 21 July 2016
Van Sambeek LL, Ratigan JL, Hansen FD (1993) Dilatancy of rock salt in laboratory tests. Int J Rock Mech Min Sci Geomech Abstr 30:735–738
Wang TT, Yan XZ, Yang XJ, Yang HL (2010) Dynamic subsidence prediction of ground surface above salt cavern gas storage considering the creep of rock salt. Sci China Tech Sci 53(12):3197–3202
Wang TT, Yan XZ, Yang HL, Yang XJ (2011) Stability analysis of the pillars between bedded salt cavern gas storages by cusp catastrophe model. Sci China Tech Sci 54:1615–1623
Wang TT, Yang CH, Yan XZ, Daemen JJK (2015) Allowable pillar width for bedded rock salt caverns gas storage. J Petrol Sci Eng 127:433–444
Wang TT, Yang CH, Ma HL, Li YP, Shi XL, Li JJ, Daemen JJK (2016) Safety evaluation of salt cavern gas storage close to an old cavern. Int J Mech Min Sci 83:95–106
Wu W, Hou ZM, Yang CH (2005) Investigations on evaluating criteria of stabilities for energy (petroleum and natural gas) storage caverns in rock salt. Chin J Rock Mech Eng 24:2497–2505 (in Chinese)
Yang CH, Daemen JJK, Yin JH (1999) Experimental investigation of creep behavior of salt rock. Int J Rock Mech Min Sci 36:233–242
Yang CH, Li YP, Chen F (2009) Mechanics theory and engineering of bedded salt rock. Science Press, Beijing (in Chinese)
Yang CH, Li YP, Zhou HW (2015a) Failure mechanism and protection of salt caverns for large-scale underground energy storage. Science Press, Beijing (in Chinese)
Yang CH, Wang TT, Li YP, Yang HJ, Li JJ, Qu DA, Xu BC, Yang Y, Daemen JJK (2015b) Feasibility analysis of using abandoned salt caverns for large-scale underground energy storage in China. Appl Energy 137:467–481
Acknowledgments
The authors wish to acknowledge the financial supports of the National Natural Science Foundation of China (grant nos. 41502296, 41472285, 51404241, 51304187) and Youth Innovation Promotion Association CAS (grant no. 2016296). Thanks go to Professor J.J.K. Daemen, Mackay School of Earth Sciences and Engineering, University of Nevada (Reno), for the careful proof-reading and constructive suggestions. We would like to thank an anonymous reviewer for their helpful and constructive comments and suggestions.
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Wang, T., Yang, C., Li, J. et al. Failure Analysis of Overhanging Blocks in the Walls of a Gas Storage Salt Cavern: A Case Study. Rock Mech Rock Eng 50, 125–137 (2017). https://doi.org/10.1007/s00603-016-1102-1
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DOI: https://doi.org/10.1007/s00603-016-1102-1