Abstract：Aiming at the current problem that thick sandwiches are commonly developed in domestic salt mines, this study investigated whether thick sandwiches would collapse to allow connection of salt deposits above and below, consequently increase leaching height and expand single cavern capacity by laboratory experiments, numerical simulation and field tests. The analysis of water-soluble mechanism and changing patterns of mechanical parameters of sandwich layers after water immersion shows that: after water immersion, sandwiches dissolve into honeycomb structure with cracks that easily flake, and the residues occupy small space; after water immersion, mechanical strength of sandwiches decrease greatly, susceptible for failure and collapse. Based on the calculation model for critical limited span, the collapse timing was predicted. In addition, laws of thick sandwiches collapse were obtained by numerical simulation, which indicate that the smaller the thickness, the larger the depth, the larger the limited span and storage height of the sandwiches, the more likely the sandwich will collapse. The design idea of “full immersion and secondary cavity construction” was proposed, and cavern leaching design for a 12 meter thick sandwich in a gas storage was made, and tests on two wells were conducted. The results prove that thick sandwiches could collapse, increasing leaching height and single cavity capacity, and the technology is technologically and economically feasible.
[1] 郑雅丽, 赵艳杰. 盐穴储气库国内外发展概况[J]. 油气储运, 2010, 29(9): 652-655, 663. ZHENG Yali, ZHAO Yanjie. General situation of salt cavern gas storage worldwide[J]. Oil & Gas Storage and Transportation, 2010, 29(9): 652-655, 663. [2] 郭彬, 房德华, 王秀平, 等. 国外盐穴地下天然气储气库建库技术发展[J]. 断块油气田, 2002, 9(1): 78-80. GUO Bin, FANG Dehua, WANG Xiuping, et al. Construction and operation of underground storage cavern of nature gas in salt cavern[J]. Fault-Block Oil & Gas Field, 2002, 9(1): 78-80. [3] 唐立根, 王皆明, 丁国生, 等. 基于开发资料预测气藏改建储气库后井底流入动态[J]. 石油勘探与开发, 2016, 43(1): 127-130. TANG Ligen, WANG Jieming, DING Guosheng, et al. Downhole inflow-performance forecast for underground gas storage based on gas reservoir development data[J]. Petroleum Exploration and Development, 2016, 43(1): 127-130. [4] 丁国生. 金坛盐穴地下储气库建库关键技术综述[J]. 天然气工业, 2007, 27(3): 111-113. DING Guosheng. General introduction on key technologies of the construction of Jintan underground salt cavern gas storage[J]. Natural Gas Industry, 2007, 27(3): 111-113. [5] 班凡生, 袁光杰, 赵志成. 盐穴储气库溶腔夹层应力分布规律[J]. 科技导报, 2014, 32(16): 45-48. BAN Fansheng, YUAN Guangjie, ZHAO Zhicheng. Stress distribution rules of interlayer in salt caverns gas storage[J]. Science & Technology Review, 2014, 32(16): 45-48. [6] 施锡林, 李银平, 杨春和, 等. 盐穴储气库水溶造腔夹层垮塌力学机制研究[J]. 岩土力学, 2009, 30(12): 3615-3620. SHI Xilin, LI Yinping, YANG Chunhe, et al. Research on mechanical mechanism of interlayer collapse in solution mining for salt cavern gas storage[J]. Rock and Soil Mechanics, 2009, 30(12): 3615-3620. [7] 施锡林, 李银平, 杨春和, 等. 多夹层盐矿油气储库水溶建腔夹层垮塌控制技术[J]. 岩土工程学报, 2011, 33(12): 1957-1963. SHI Xilin, LI Yinping, YANG Chunhe, et al. Collapse control technology for interbeds in solution mining for oil/gas storage in multi-interbedded salt formation[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(12): 1957-1963. [8] 姜德义, 张军伟, 陈结, 等. 岩盐储库建腔期难溶夹层的软化规律研究[J]. 岩石力学与工程学报, 2014, 33(5): 865-873. JIANG Deyi, ZHANG Junwei, CHEN Jie, et al. Research on softening law of insoluble interlayer during salt cavern building[J]. Chinese Journal of Rock Mechanics and Engineering, 2014, 33(5): 865-873. [9] 郭凯, 李建君, 郑贤斌. 盐穴储气库造腔过程夹层处理工艺: 以西气东输金坛储气库为例[J]. 油气储运, 2015, 34(2): 162-166. GUO Kai, LI Jianjun, ZHENG Xianbin. Interlayer treatment process in cavity building for salt cavern gas storage: A case study of Jintan Gas Storage of West-to-East Gas Pipeline[J]. Oil & Gas Storage and Transportation, 2015, 34(2): 162-166. [10] 袁炽. 层状盐岩储库夹层垮塌的理论分析[J]. 科学技术与工程, 2015, 15(2): 14-20. YUAN Chi. Theoretical analysis of the interlayer collapse in solution mining of the salt cavern[J]. Science Technology and Engineering, 2015, 15(2): 14-20. [11] 孟涛, 梁卫国, 陈跃都, 等. 层状盐岩溶腔建造过程中石膏夹层周期性垮塌理论分析[J]. 岩石力学与工程学报, 2015, 34(增刊1): 3267-3273. MENG Tao, LIANG Weiguo, CHEN Yuedu, et al. Theoretical analysis of periodic fracture for gypsum interlayer during construction of bedded salt cavern[J]. Chinese Journal of Rock Mechanics and Engineering, 2015, 34(Supp. 1): 3267-3273.
2017, Vol. 44 
