水合物沉积物的力学本构模型及参数离散元计算
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摘要
为有效描述水合物沉积物在不同水合物饱和度与围压情况下的力学行为,该文基于广义Hooke(胡克)定律建立了水合物沉积物的应力-应变关系方程和弹性模量弱化方程;基于三轴压缩试验确定了水合物沉积物的软化系数和软化指数,基于颗粒流程序(PFC~(3D))开发了水合物沉积物初始弹性模量的离散元算法(DEM).利用建立的应力-应变关系方程、弹性模量弱化方程和初始弹性模量DEM,数值模拟了水合物沉积物在6种不同水合物饱和度与围压情况下的力学行为.数值模拟结果与三轴压缩试验结果的对比表明,建立的应力-应变关系方程、弹性模量弱化方程和初始弹性模量DEM,能有效预测水合物沉积物的力学行为,可为水合物井筒设计与安全开采提供理论基础和计算方法.
To soundly describe the mechanical behaviors of hydrate-bearing sediments in the cases of different saturation levels of hydrate and various confining pressures, the stress-strain relation equations and elastic modulus weak-form equations for hydrate-bearing sediments were developed based on the generalized Hooke's law. The softening coefficient and softening exponent of the hydrate-bearing sediments were determined according to the triaxial compression test results. A discrete element method(DEM) to calculate the initial elastic moduli of hydrate-bearing sediments was proposed based on the 3 D particle flow code(PFC~(3 D)). The mechanical behaviors of hydrate-bearing sediments under 6 various conditions related to saturation levels of hydrate and confining pressures, were numerically simulated with the stress-strain relation equations, elastic modulus softening equations and the DEM together. Numerical results show that, the proposed stress-strain relation equations, elastic modulus softening equations and the DEM can effectively predict the mechanical behaviors of hydrate-bearing sediments under various saturation levels of hydrate and confining pressures. The work gives a theoretical basis and a computational method for the investigations on the mechanical behaviors of hydrate boreholes and the safe exploitation of hydrate.
To soundly describe the mechanical behaviors of hydrate-bearing sediments in the cases of different saturation levels of hydrate and various confining pressures, the stress-strain relation equations and elastic modulus weak-form equations for hydrate-bearing sediments were developed based on the generalized Hooke's law. The softening coefficient and softening exponent of the hydrate-bearing sediments were determined according to the triaxial compression test results. A discrete element method(DEM) to calculate the initial elastic moduli of hydrate-bearing sediments was proposed based on the 3 D particle flow code(PFC~(3 D)). The mechanical behaviors of hydrate-bearing sediments under 6 various conditions related to saturation levels of hydrate and confining pressures, were numerically simulated with the stress-strain relation equations, elastic modulus softening equations and the DEM together. Numerical results show that, the proposed stress-strain relation equations, elastic modulus softening equations and the DEM can effectively predict the mechanical behaviors of hydrate-bearing sediments under various saturation levels of hydrate and confining pressures. The work gives a theoretical basis and a computational method for the investigations on the mechanical behaviors of hydrate boreholes and the safe exploitation of hydrate.
引文
[1] 思娜, 安雷, 邓辉, 等. 天然气水合物开采技术研究进展及思考[J]. 中国石油勘探, 2016, 21(5): 52-61.(SI Na, AN Lei, DENG Hui, et al. Discussion on natural gas hydrate production technologies[J]. China Petroleum Exploration, 2016, 21(5): 52-61.(in Chinese))
[2] 张旭辉, 鲁晓兵, 刘乐乐. 天然气水合物开采方法研究进展[J]. 地球物理学进展, 2014, 29(2): 858-869.(ZHANG Xuhui, LU Xiaobing, LIU Lele. Advances in natural gas hydrate recovery methods[J]. Progress in Geophysics, 2014, 29(2): 858-869.(in Chinese))
[3] SULTAN N, COCHONAT P, FOUCHER J P, et al. Effect of gas hydrates melting on seafloor slope instability[J]. Marine Geology, 2004, 213(1/4): 379-401.
[4] 于锋, 宋永臣, 李洋辉, 等. 含冰甲烷水合物的应力与应变关系[J]. 石油学报, 2011, 32(4): 687-692.(YU Feng, SONG Yongchen, LI Yanghui, et al. A study on stress-strain relations of methane hydrates[J]. Acta Petrolei Sinica, 2011, 32(4): 687-692.(in Chinese))
[5] SONG Y, YU F, LI Y, et al. Mechanical property of artificial methane hydrate under triaxial compression[J]. Journal of Energy Chemistry, 2010, 19(3): 246-250.
[6] LI Y, LIU W, ZHU Y, et al. Mechanical behaviors of permafrost-associated methane hydrate-bearing sediments under different mining methods[J]. Applied Energy, 2016, 162: 1627-1632.
[7] 鲁晓兵, 张旭辉, 石要红, 等. 黏土水合物沉积物力学特性及应力应变关系[J]. 中国海洋大学学报(自然科学版), 2017, 47(10): 9-13.(LU Xiaobing, ZHANG Xuhui, SHI Yaohong, et al. Mechanical properties of hydrate-bearing silty-clay and stress-strain relation[J]. Periodical of Ocean University of China, 2017, 47(10): 9-13.(in Chinese))
[8] ZHU Y, LI Y, LIU W, et al. Dynamic strength characteristics of methane hydrate-bearing sediments under seismic load[J]. Journal of Natural Gas Science & Engineering, 2015, 26: 608-616.
[9] ZHANG X, LIU L, ZHOU J, et al. A model for the elastic modulus of hydrate-bearing sediments[J]. International Journal of Offshore & Polar Engineering, 2015, 25(4): 314-319.
[10] YU F, SONG Y, LIU W, et al. Analyses of stress strain behavior and constitutive model of artificial methane hydrate[J]. Journal of Petroleum Science & Engineering, 2011, 77(2): 183-188.
[11] YU F, SONG Y, LI Y, et al. Analysis of stress-strain behavior and constitutive relation of methane hydrate-bearing sediments with various porosity[J]. International Journal of Offshore & Polar Engineering, 2011, 21(4): 316-322.
[12] SONG Y, ZHU Y, LIU W, et al. Experimental research on the mechanical properties of methane hydrate-bearing sediments during hydrate dissociation[J]. Marine & Petroleum Geology, 2014, 51(2): 70-78.
[13] SONG Y, ZHU Y, LIU W, et al. The effects of methane hydrate dissociation at different temperatures on the stability of porous sediments[J]. Journal of Petroleum Science & Engineering, 2016, 147: 77-86.
[14] 吴二林, 魏厚振, 颜荣涛, 等. 考虑损伤的含天然气水合物沉积物本构模型[J]. 岩石力学与工程学报, 2012, 31(S1): 3045-3050.(WU Erlin, WEI Houzhen, YAN Rongtao, et al. Constitutive model for gas hydrate-bearing sediments considering damage[J]. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(S1): 3045-3050.(in Chinese))
[15] 杨期君, 赵春风. 含气水合物沉积物弹塑性损伤本构模型探讨[J]. 岩土力学, 2014, 35(4): 991-997.(YANG Qijun, ZHAO Chunfeng. A constitutive model coupling elastoplasticity and damage formethane hydrate-bearing sediments[J]. Rock and Soil Mechanics, 2014, 35(4): 991-997.(in Chinese))
[16] 刘乐乐, 张旭辉, 刘昌岭, 等. 含水合物沉积物三轴剪切试验与损伤统计分析[J]. 力学学报, 2016, 48(3): 720-729.(LIU Lele, ZHANG Xuhui, LIU Changling, et al. Triaxial shear tests and statistical analyses of damage for methane hydrate-bearing sediments[J]. Chinese Journal of Theoretical and Applied Mechanics, 2016, 48(3): 720-729.(in Chinese))
[17] 李彦龙, 刘昌岭, 刘乐乐, 等. 含水合物松散沉积物三轴试验及应变关系模型[J]. 天然气地球科学, 2017, 28(3): 383-390.(LI Yanlong, LIU Changling, LIU Lele, et al. Triaxial shear test and strain analysis of unconsolidated hydrate-bearing sediments[J]. Natural Gas Geoscience, 2017, 28(3): 383-390.(in Chinese))
[18] 李彦龙, 刘昌岭, 刘乐乐. 含水合物沉积物损伤统计本构模型及其参数确定方法[J]. 石油学报, 2016, 37(10): 1273-1279.(LI Yanlong, LIU Changling, LIU Lele. Damage statistic constitutive model of hydrate-bearing sediments and the determination method of parameters[J]. Acta Petrolei Sinica, 2016, 37(10): 1273-1279.(in Chinese))
[19] 颜荣涛, 梁维云, 韦昌富, 等. 考虑赋存模式影响的含水合物沉积物的本构模型研究[J]. 岩土力学, 2017, 38(1): 10-18.(YAN Rongtao, LIANG Weiyun, WEI Changfu, et al. A constitutive model for gas hydrate-bearing sediments considering hydrate occurring habits[J]. Rock and Soil Mechanics, 2017, 38(1): 10-18.(in Chinese))
[20] MASUI A, HANEDA H, OGATA Y, et al. Effects of methane hydrate formation on shear strength of synthetic methane hydrate sediments[C]//International Society of Offshore and Polar Engineers Conference. Seoul, 2005: 364-369.
[21] LIU L, ZHANG X, LI Y, et al. A damage-softening statistical constitutive model of composite hydrate-bearing sediments[C]//9th International Conference on Gas Hydrates. Denver, Colorado, 2017.
[2] 张旭辉, 鲁晓兵, 刘乐乐. 天然气水合物开采方法研究进展[J]. 地球物理学进展, 2014, 29(2): 858-869.(ZHANG Xuhui, LU Xiaobing, LIU Lele. Advances in natural gas hydrate recovery methods[J]. Progress in Geophysics, 2014, 29(2): 858-869.(in Chinese))
[3] SULTAN N, COCHONAT P, FOUCHER J P, et al. Effect of gas hydrates melting on seafloor slope instability[J]. Marine Geology, 2004, 213(1/4): 379-401.
[4] 于锋, 宋永臣, 李洋辉, 等. 含冰甲烷水合物的应力与应变关系[J]. 石油学报, 2011, 32(4): 687-692.(YU Feng, SONG Yongchen, LI Yanghui, et al. A study on stress-strain relations of methane hydrates[J]. Acta Petrolei Sinica, 2011, 32(4): 687-692.(in Chinese))
[5] SONG Y, YU F, LI Y, et al. Mechanical property of artificial methane hydrate under triaxial compression[J]. Journal of Energy Chemistry, 2010, 19(3): 246-250.
[6] LI Y, LIU W, ZHU Y, et al. Mechanical behaviors of permafrost-associated methane hydrate-bearing sediments under different mining methods[J]. Applied Energy, 2016, 162: 1627-1632.
[7] 鲁晓兵, 张旭辉, 石要红, 等. 黏土水合物沉积物力学特性及应力应变关系[J]. 中国海洋大学学报(自然科学版), 2017, 47(10): 9-13.(LU Xiaobing, ZHANG Xuhui, SHI Yaohong, et al. Mechanical properties of hydrate-bearing silty-clay and stress-strain relation[J]. Periodical of Ocean University of China, 2017, 47(10): 9-13.(in Chinese))
[8] ZHU Y, LI Y, LIU W, et al. Dynamic strength characteristics of methane hydrate-bearing sediments under seismic load[J]. Journal of Natural Gas Science & Engineering, 2015, 26: 608-616.
[9] ZHANG X, LIU L, ZHOU J, et al. A model for the elastic modulus of hydrate-bearing sediments[J]. International Journal of Offshore & Polar Engineering, 2015, 25(4): 314-319.
[10] YU F, SONG Y, LIU W, et al. Analyses of stress strain behavior and constitutive model of artificial methane hydrate[J]. Journal of Petroleum Science & Engineering, 2011, 77(2): 183-188.
[11] YU F, SONG Y, LI Y, et al. Analysis of stress-strain behavior and constitutive relation of methane hydrate-bearing sediments with various porosity[J]. International Journal of Offshore & Polar Engineering, 2011, 21(4): 316-322.
[12] SONG Y, ZHU Y, LIU W, et al. Experimental research on the mechanical properties of methane hydrate-bearing sediments during hydrate dissociation[J]. Marine & Petroleum Geology, 2014, 51(2): 70-78.
[13] SONG Y, ZHU Y, LIU W, et al. The effects of methane hydrate dissociation at different temperatures on the stability of porous sediments[J]. Journal of Petroleum Science & Engineering, 2016, 147: 77-86.
[14] 吴二林, 魏厚振, 颜荣涛, 等. 考虑损伤的含天然气水合物沉积物本构模型[J]. 岩石力学与工程学报, 2012, 31(S1): 3045-3050.(WU Erlin, WEI Houzhen, YAN Rongtao, et al. Constitutive model for gas hydrate-bearing sediments considering damage[J]. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(S1): 3045-3050.(in Chinese))
[15] 杨期君, 赵春风. 含气水合物沉积物弹塑性损伤本构模型探讨[J]. 岩土力学, 2014, 35(4): 991-997.(YANG Qijun, ZHAO Chunfeng. A constitutive model coupling elastoplasticity and damage formethane hydrate-bearing sediments[J]. Rock and Soil Mechanics, 2014, 35(4): 991-997.(in Chinese))
[16] 刘乐乐, 张旭辉, 刘昌岭, 等. 含水合物沉积物三轴剪切试验与损伤统计分析[J]. 力学学报, 2016, 48(3): 720-729.(LIU Lele, ZHANG Xuhui, LIU Changling, et al. Triaxial shear tests and statistical analyses of damage for methane hydrate-bearing sediments[J]. Chinese Journal of Theoretical and Applied Mechanics, 2016, 48(3): 720-729.(in Chinese))
[17] 李彦龙, 刘昌岭, 刘乐乐, 等. 含水合物松散沉积物三轴试验及应变关系模型[J]. 天然气地球科学, 2017, 28(3): 383-390.(LI Yanlong, LIU Changling, LIU Lele, et al. Triaxial shear test and strain analysis of unconsolidated hydrate-bearing sediments[J]. Natural Gas Geoscience, 2017, 28(3): 383-390.(in Chinese))
[18] 李彦龙, 刘昌岭, 刘乐乐. 含水合物沉积物损伤统计本构模型及其参数确定方法[J]. 石油学报, 2016, 37(10): 1273-1279.(LI Yanlong, LIU Changling, LIU Lele. Damage statistic constitutive model of hydrate-bearing sediments and the determination method of parameters[J]. Acta Petrolei Sinica, 2016, 37(10): 1273-1279.(in Chinese))
[19] 颜荣涛, 梁维云, 韦昌富, 等. 考虑赋存模式影响的含水合物沉积物的本构模型研究[J]. 岩土力学, 2017, 38(1): 10-18.(YAN Rongtao, LIANG Weiyun, WEI Changfu, et al. A constitutive model for gas hydrate-bearing sediments considering hydrate occurring habits[J]. Rock and Soil Mechanics, 2017, 38(1): 10-18.(in Chinese))
[20] MASUI A, HANEDA H, OGATA Y, et al. Effects of methane hydrate formation on shear strength of synthetic methane hydrate sediments[C]//International Society of Offshore and Polar Engineers Conference. Seoul, 2005: 364-369.
[21] LIU L, ZHANG X, LI Y, et al. A damage-softening statistical constitutive model of composite hydrate-bearing sediments[C]//9th International Conference on Gas Hydrates. Denver, Colorado, 2017.