Multiphase flow computational model for extraction of gas hydrates in marine soft soils
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摘要: 天然气水合物是一种储量巨大的非常规清洁能源,其安全、高效开采对于保障我国能源安全意义重大。降压法是目前水合物开采中使用最广、最具前景的一种开采方式。本文针对水合物降压开采中动态多相渗流过程开展理论及数值模拟研究。考虑水合物分解与多相渗流之间的动态耦合,建立了耦合水合物动力学分解与多孔介质非饱和渗流的数学模型,并基于COMSOL多物理场耦合有限元软件进行数值实现。模型通过与Masuda水合物分解试验进行对比验证了有效性。基于数学模型对水合物开采的关键影响因素开展敏感性分析,分析结果表明:水合物饱和度降低速率随储层渗透率、降压幅度的增加而加快。Abstract: The gas hydrate is a type of unconventional clean energy with substantial reserves. The successful and safely extraction of gas hydrates is of great significance in guaranteeing the energy safety of China. At present the depressurization method is a kind of the most widely used and promising extraction means for the gas hydrates. The problems of multiphase flow in the reservoir caused by hydrate phase transition are studied theoretically and numerically. Firstly, a mathematical model for coupling the kinetic decomposition of the gas hydrates and the multiphase flow in porous media is established. The proposed model is numerically implemented by the software COMSOL Multiphysics, and its effectiveness is validated through the Masuda's experiments. Then, the sensitivity analysis for the key factors which have impact on the extraction of the gas hydrates is conducted. The results show that the gas production rate increases with the increase of the permeability and pressure drop amplitude.
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Keywords:
- gas hydrate /
- depressurization method /
- multiphase flow /
- phase transition /
- energy geotechnics
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表 1 数值模型参数表
Table 1 Parameters of numerical model
物性参数 取值 单位 初始水合物饱和度 0.443 — 初始水饱和度 0.351 — 储层孔隙度 0.182 — 储层绝对渗透率 96.7 mD 初始孔隙压力 3.75 MPa 降压边界压力 2.84 MPa 水合物地层温度 275.45 K 水的密度ρw 1000 kg/m3 甲烷天然气密度ρg 0.684 kg/m3 水合物密度ρh 917 kg/m3 水合物摩尔质量Mh 0.124 kg/mol 甲烷天然气摩尔质量Mg 0.016 kg/mol 水摩尔质量Mw 0.018 kg/mol 气相动力黏度μg 1.84×10 -5 Pa·s 液相动力黏度μw 1.01×10-5 Pa·s 液相残余饱和度Swr 0.1 — 气相残余饱和度Sgr 0.05 — VG模型参数m 0.45 — 初始毛细管力pc0 1 kPa 表 2 敏感性分析参数表
Table 2 Parameters for sensitivity analysis
编号 影响因素 取值 单位 1 初始渗透率 40,60,80,100 mD 2 井筒降压大小 1.5,2.0,2.5,2.84 MPa -
[1] SUM A K, KOH C A, SLOAN E D. Clathrate hydrates: from laboratory science to engineering practice[J]. Industrial & Engineering Chemistry Research, 2009, 48(16): 7457–7465.
[2] 田慧会, 韦昌富, 颜荣涛, 等. 粉土中二氧化碳水合物分解过程的核磁试验研究[J]. 中国科学: 物理学力学天文学, 2019, 49(3): 173–180. doi: 10.3969/j.issn.0253-2778.2019.03.001 TIAN Hui-hui, WEI Chang-fu, YAN Rong-tao, et al. A NMR-based analysis of carbon dioxide hydrate dissociation process in silt[J]. Scientia Sinica (Physica, Mechanica & Astronomica), 2019, 49(3): 173–180. (in Chinese) doi: 10.3969/j.issn.0253-2778.2019.03.001
[3] DAI S, SEOL Y. Water permeability in hydrate-bearing sediments: A pore-scale study[J]. Geophysical Research Letters, 2014, 41(12): 4176–4184. doi: 10.1002/2014GL060535
[4] 刘乐乐, 张准, 宁伏龙, 等. 含水合物沉积物渗透率分形模型[J]. 中国科学: 物理学力学天文学, 2019, 49(3): 165–172. https://www.cnki.com.cn/Article/CJFDTOTAL-JGXK201903013.htm LIU Le-le, ZHANG Zhun, NING Fu-long, et al. A fractal model for the relative permeability prediction of hydrate-bearing sediments[J]. Scientia Sinica (Physica, Mechanica & Astronomica), 2019, 49(3): 165–172. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-JGXK201903013.htm
[5] SINGH H, MYSHAKIN E M, SEOL Y. A nonempirical relative permeability model for hydrate-bearing sediments[J]. Society of Petroleum Engineers Journal, 2019, 24(2): 547–562.
[6] 蔡建超, 夏宇轩, 徐赛, 等. 含水合物沉积物多相渗流特性研究进展[J]. 力学学报, 2020, 52(1): 208–223. https://www.cnki.com.cn/Article/CJFDTOTAL-LXXB202001019.htm CAI Jian-chao, XIA Yu-xuan, XU Sai, et al. Advances in multiphase seepage characteristics of natural gas hydrate sediments[J]. Chinese Journal of Theoretical and Applied Mechanics, 2020, 52(1): 208–223. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-LXXB202001019.htm
[7] KIM H C, BISHNOI P R, HEIDEMANN R A, et al. Kinetics of methane hydrate decomposition[J]. Chemical Engineering Science, 1987, 42(7): 1645–1653. doi: 10.1016/0009-2509(87)80169-0
[8] SUN X, NANCHARY N, MOHANTY K K. 1-D modeling of hydrate depressurization in porous media[J]. Transport in Porous Media, 2005, 58(3): 315–338. doi: 10.1007/s11242-004-1410-x
[9] KAMATH V A. A perspective on gas production from hydrates[C]// JNOC's Methane Hydrate International Symposium, 1998: 20–22.
[10] SUN X, LUO H, SOGA K. A coupled thermal-hydraulic- mechanical-chemical (THMC) model for methane hydrate bearing sediments using COMSOL Multiphysics[J]. Journal of Zhejiang University-SCIENCE A, 2018, 19(8): 600–623. doi: 10.1631/jzus.A1700464
[11] VAN GENUCHTEN M T. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J]. Soil Science Society of America Journal, 1980, 44(5): 892–898. doi: 10.2136/sssaj1980.03615995004400050002x
[12] MASUDA Y. Numerical calculation of gas production performance from reservoirs containing natural gas hydrates[C]// Annual Technical Conference, San Antonio, Texas, 1997.
[13] HARDWICK J S, MATHIAS S A. Masuda's sandstone core hydrate dissociation experiment revisited[J]. Chemical Engineering Science, 2018, 175: 98–109. doi: 10.1016/j.ces.2017.09.003
-
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