作者中心
专家审稿
编委审稿
主编审稿
3D NUMERICAL EVALUATION OF GAS HYDRATE PRODUCTION PER FORMANCE OF THE DEPRESSURIZATION AND BACKFILLING WITH IN-SITU SUPPLEMENTAL HEAT METHOD
-
摘要: 天然气水合物是未来极具潜力的新型高效清洁替代能源。在分析水合物开采面临的瓶颈问题的基础上，提出了一种全新的天然气水合物开采方法——原位补热降压充填开采法。该方法将氧化钙(CaO)粉末注入天然水合物储层，降压开采天然气，天然气水合物分解产生的水和氧化钙粉末迅速反应，产生的大量热量补充天然气水合物的分解热。本文利用基于有限体积法的新型天然气水合物模拟器，构建三维地质模型对该方法进行产能数值模拟评价。模拟结果表明相较于常规水平井方法以及水平井结合压裂开采方案，该方法对生产的促进效应明显，尤其是与水平井结合压裂开采方案相比该方法的累积产气量明显提高，但累积产水量没有显著变化，开采效率显著提升。施工工艺中裂缝等效渗透率和氧化钙注入量两个关键参数的敏感性分析结果表明在压裂过程中，压裂技术的增产效果会随着等效渗透率的提高而逐渐减弱。除此之外，氧化钙注入量越大，增产效应越明显，并且提高氧化钙注入量只会提高产气量，不会显著提高产水量，所以理论上注入量越大，产气效率越高。与此同时，该方法在不同渗透性能的天然气水合物储层中均有一定的适用性，其中针对低渗储层的促进效应更为显著。综合上述结论，本文从三维模型理论计算的角度定量化验证了原位补热降压充填开采方法的潜在价值，期待为将来的水合物试采工作提供一定参考。Abstract: Natural gas hydrate(NGH) is a promising clean alternative energy resource for world in future. Based on the analysis of the challenges in the commercial exploitation, the depressurization and backfilling with in-situ supplemental heat method had been proposed to enhance the gas production of methane hydrate reservoir. In this method, the calcium oxide(CaO) powder is injected into the hydrate reservoir, and the natural gas is exploited by depressurization. The water produced by the decomposition of natural gas hydrate will react with the calcium oxide powder rapidly, which would provide amounts heat for supplement thermal energy of the decomposition of natural gas hydrate. This novel method is evaluated by a numerical simulator based on the finite volume method in this work. A three-dimensional reservoir model was constructed. The simulation results indicate that comparing with the conventional horizontal well method and the horizontal well combined fracturing method, this method has a better production performance. Comparing with the horizontal well combined fracturing method, the cumulative gas production of this method is improved, but the cumulative water production has changed slightly simultaneously. Therefore, the recovery efficiency has been significantly improved. The results of the sensitivity analysis of the equivalent permeability of fractures and the mass of CaO injection show that the increasing effect of fracturing on gas production declines with the improvement of equivalent permeability of fractures. In addition, the greater the amount of injected calcium oxide, the more obvious the effect of increasing production. Increasing the amount of injected calcium oxide only increase the gas production, but not significantly increase the water production. Therefore, theoretically the larger the injection, the higher the gas production efficiency. Simultaneously, the feasibility of this method has been testified in reservoirs with different flow capacity. Herein, the improving effect on low-permeability reservoir is more obviously than other cases. Based on the above conclusions, this work quantitatively verifies the potential value of the depressurization and backfilling with in-situ supplemental heat method from the perspective of the theoretical calculation of the three-dimensional model, which looks forward to providing the reference for following work of hydrate recovery.
-
图 1 天然气水合物原位补热降压充填开采方法示意图(李守定等，2020)
Figure 1. Schematics of the method of depressurization and backfilling with in-situ supplemental heat(Li et al., 2020)
图 3 本文模拟方法与T+H模拟器水合物分解产生甲烷气体速率比较
Figure 3. Comparison of the volumetric rates of CH4 release from hydrate dissociation between self-developed simulator and T+H
图 4 本文模拟方法与T+H模拟器水合物分解累积产生甲烷气体量比较
Figure 4. Comparison of the cumulative volumes of CH4 release from hydrate dissociation between self-developed simulator and T+H
图 6 岩芯尺度数值模拟出口温度演变
a. t=4min；b. t=6min；c. t=8min；d. t=15min；e. t=30min
Figure 6. The variation of the outlet temperature and the numerical modelling of this work
图 7 不同网格数量下累积产气量比较
Figure 7. Comparison of cumulative gas production under different grid numbers
图 8 不同网格数量下累积产水量比较
Figure 8. Comparison of cumulative water production under different grid numbers
图 9 天然气水合物储层地质模型示意图
Figure 9. Schematic diagram of numerical simulation geological model of hydrate reservoir
图 10 数值计算模拟网格示意图
Figure 10. Schematic of the mesh structure used in the numerical simulation
图 11 模拟储层天然气水合物饱和度时空演化规律
a. 常规水平井开采方法；b. 水平井结合压裂开采方法；c. 水平井结合压裂及氧化钙注入开采方法
Figure 11. Temporal and spatial evolution of the hydrate saturation(S_hyd)in the simulated reservoir
图 12 参考计算案例累积产气量演化
case 1. 常规水平井方案；case 2-1.水平井结合压裂；case 3-1. 水平井结合压裂及氧化钙注入
Figure 12. Evolution of cumulative gas production in the base cases
图 13 参考计算案例累积产水量演化
case 1. 常规水平井方案；case 2-1. 水平井结合压裂；case 3-1. 水平井结合压裂及氧化钙注入
Figure 13. Evolution of cumulative gas production in the base cases
图 14 参考计算案例累积气水比演化
case 1. 常规水平井方案；case 2-1. 水平井结合压裂；case 3-1. 水平井结合压裂及氧化钙注入
Figure 14. Evolution of gas water ratio in the base cases
图 15 模拟储层温度时空演化规律
a. 常规水平井开采方法；b. 水平井结合压裂开采方法；c. 水平井结合压裂及氧化钙注入开采方法
Figure 15. Temporal and spatial evolution of the temperature in the simulated reservoir
图 16 模拟储层压力时空演化规律
a. 常规水平井开采方法；b. 水平井结合压裂开采方法；c. 水平井结合压裂及氧化钙注入开采方法
Figure 16. Temporal and spatial evolution of the pressure in the simulated reservoir
图 17 不同裂缝等效渗透率累积产气量演化
case 1. 未压裂；case 2-1. 10mD；case 2-2. 40mD；case 2-3. 70mD；case 2-4. 100mD
Figure 17. Evolution of cumulative gas production in the cases of different fracture equivalent permeability
图 18 不同裂缝等效渗透率累积产水量演化
case 1. 未压裂；case 2-1. 10mD；case 2-2. 40mD；case 2-3. 70mD；case 2-4. 100mD
Figure 18. Evolution of cumulative water production in the cases of different fracture equivalent permeability
图 19 不同裂缝等效渗透率气水比演化
case 1. 未压裂；case 2-1. 10mD；case 2-2. 40mD；case 2-3. 70mD；case 2-4. 100mD
Figure 19. Evolution of gas water ratio in the cases of different fracture equivalent permeability
图 20 不同氧化钙注入量累积产气量演化
case 2-1. 未注入；case 3-1. 5t；case 3-2. 10t；case 3-3. 15t；case 3-4. 20t
Figure 20. Evolution of cumulative gas production in the cases of different CaO injection mass
图 21 不同氧化钙注入量累积产水量演化
case 2-1. 未注入；case 3-1. 5 t；case 3-2. 10 t；case 3-3. 15 t；case 3-4. 20 t
Figure 21. Evolution of cumulative water production in the cases of different CaO injection mass
图 22 不同氧化钙注入量气水比演化
case 2-1. 未注入；case 3-1. 5 t；case 3-2. 10 t；case 3-3. 15 t；case 3-4. 20 t
Figure 22. Evolution of gas water ratio in the cases of different CaO injection mass
图 23 不同含水合物沉积物层渗透率累积产气量演化
case 4-1. 5 t/1 mD；case 4-2. 5 t/10 mD；case 4-3. 5 t/20 mD；case 4-4. 5 t/30 mD
Figure 23. Evolution of cumulative gas production in the cases of different permeability of HBL
图 24 不同含水合物沉积物层渗透率累积产水量演化
case 4-1. 5 t/1 mD；case 4-2. 5 t/10 mD；case 4-3. 5 t/20 mD；case 4-4. 5 t/30 mD
Figure 24. Evolution of cumulative water production in the cases of different permeability of HBL
图 25 不同含水合物沉积物层渗透率累积气水比演化
case 4-1. 5 t/1 mD；case 4-2. 5 t/10 mD；case 4-3. 5 t/20 mD；case 4-4. 5 t/30 mD
Figure 25. Evolution of gas water ratio in the cases of different permeability of HBL
表 1 T+H手册参考算例参数设置(Moridis，2014)
Table 1. Model settings of the reference case in T+H manual(Moridis, 2014)
参数 取值 模型长度/m 1 网格数 10 初始压力/MPa 4 初始温度/K 274.35 边界温度/K 318.15 孔隙度 0.3 本征渗透率/mD 30 热导系数/W·(m·K)-1 3.1 
下载: 导出CSV
表 2 岩芯尺度模型主要物性及参数设置
Table 2. The parameters used in the core-scale model
参数 取值 圆柱长度/cm 15.0 圆柱内径/cm 2.5 边界温度/℃ 2.5 初始气体压力/MPa 3.33 出口压力/MPa 0.1 渗透率/mD 20 导热系数/W·(m·K)-1 1.75 孔隙度 0.38 初始水合物质量/g 13.2
下载: 导出CSV
表 3 网格依赖性验证算例主要物性及参数设置
Table 3. The main physical properties and parameter settings of the grid dependence verification case
参数 取值 含水合物沉积物层厚/m 20 上覆层厚度/m 15 下伏层厚度/m 15 模型长度/m 50 模型顶面初始压力/MPa 14.6 模型顶面初始温度/K 286 模型固有渗透率/mD 1 含水合物沉积层初始水合物饱和度 0.44 含水合物沉积层初始水饱和度 0.56 热导系数/W·(m·K)-1 2 孔隙度 0.3
下载: 导出CSV
表 4 储层模型主要物性及参数设置
Table 4. Main physical properties and parameters of reservoirs model in this work
参数 取值 参数 取值 含水合物沉积物层厚/m 20 孔隙度 0.3 上覆层厚度/m 30 固有渗透率/mD 1 下伏层厚度/m 30 裂缝等效渗透率/mD 10~100 含水合物沉积层底初始压力/MPa 15.9 干热导率/W·(m·K)-1 1.0 含水合物沉积层底初始温度/K 288 湿热导率/W·(m·K)-1 3.1 含水合物沉积层初始水合物饱和度 0.44 残余水饱和度 0.3 含水合物沉积层初始水饱和度 0.56 残余气饱和度 0.05 渗透率降低系数nA 4.5 地温梯度/K·km-1 45 渗透率降低系数nG 3.5 van Genuchten系数/m 0.45 相对渗透率模型(水) 相对渗透率模型(气) $ {k_{{\rm{rA}}}} = \max \left\{ {0, \min \left\{ {{{\left[ {\frac{{{S_{\rm{A}}} - {S_{{\rm{irA}}}}}}{{1 - {S_{{\rm{irA}}}}}}} \right]}^n}} \right\}, 1} \right\}$ ${k_{{\rm{rG}}}} = \max \left\{ {0, \min \left\{ {{{\left[ {\frac{{{S_{\rm{G}}} - {S_{{\rm{irG}}}}}}{{1 - {S_{{\rm{irA}}}}}}} \right]}^{{n_{\rm{G}}}}}} \right\}, 1} \right\} $
下载: 导出CSV
表 5 计算案例设置
Table 5. Basic cases description
编号 裂缝等效渗透率/mD 氧化钙注入/t 含水合物沉积物层渗透率/mD 1 / / 1 2-1 10 / 1 2-2 40 / 1 2-3 70 / 1 2-4 100 / 1 3-1 10 5 1 3-2 10 10 1 3-3 10 15 1 3-4 10 20 1 4-1 40 5 1 4-2 40 5 10 4-3 40 5 20 4-4 40 5 30
下载: 导出CSV
表 6 氧化钙注入理论供热值及理论消耗水量
Table 6. Ideal heat supplement and water consumption of CaO injection
编号 氧化钙注入量/t 理论供热值/J 理论耗水量/m3 3-1 5 6.0×109 1.6 3-2 10 1.2×1010 3.2 3-3 15 1.8×1010 4.8 3-4 20 2.4×1010 6.4
下载: 导出CSV
-
Boswell R, Collett T S. 2011. Current perspectives on gas hydrateresources[J]. Energy & Environmental Science, 4 (4): 1206-1215. Chen C, Yang L, Jia R, et al. 2017. Simulation study on the effect of fracturing technology on the production efficiency of natural gashydrate[J]. Energies, 10(8): 1241. doi: 10.3390/en10081241 Chen L, Yamada H, Kanda Y, et al. 2017. Investigation on the dissociation flow of methane hydrate cores: Numerical modeling and experimental verification[J]. Chemical Engineering Science, 163 : 31-43. doi: 10.1016/j.ces.2017.01.032 Criado Y A, Alonso M, Abanades J C. 2014. Kinetics of the CaO/Ca(OH)2 hydration/dehydration reaction for thermochemical energy storageapplications[J]. Industrial & Engineering Chemistry Research, 53 (32): 12594-12601. Feng Y C, Chen L, Suzuki A, et al. 2019. Enhancement of gas production from methane hydrate reservoirs by the combination of hydraulic fracturing and depressurization method[J]. Energy Conversion and Management, 184 : 194-204. doi: 10.1016/j.enconman.2019.01.050 Guo K, Fan S S, Wang Y H, et al. 2020. Physical and chemical characteristics analysis of hydrate samples from northern South ChinaSea[J]. Journal of Natural Gas Science and Engineering, 81: 103476. doi: 10.1016/j.jngse.2020.103476 Huang L, Yin Z, Wan Y, et al. 2020. Evaluation and comparison of gas production potential of the typical four gas hydrate deposits in Shenhu area, South ChinaSea[J]. Energy, 204: 117955. doi: 10.1016/j.energy.2020.117955 International Journal of Energy Research, 41 (7): 1004-1013. Ito T, Igarashi A, Yamamoto K. 2011. Laboratory experiments of hydraulic fracturing in unconsolidatedsands[J]. Journal of MMIJ, 127(6-7): 243-248. http://www.researchgate.net/publication/274823852_Laboratory_Experiments_of_Hydraulic_Fracturing_in_Unconsolidated_Sands Ju X, Liu F, Fu P, et al. 2020. Gas production from hot water circulation through hydraulic fractures in methane hydrate-bearing sediments: thc-coupled simulation of production mechanisms[J]. Energy & Fuels, 34 (4): 4448-4465. doi: 10.1021/acs.energyfuels.0c00241 Kamath V A. 1984. Study of heat transfer characteristics during dissociation of gas hydrates in porous media[R]. PA, USA: Pittsburgh University. Konno Y, Jin Y, Yoneda J, et al. 2016. Hydraulic fracturing in methane-hydrate-bearingSand[J]. RSC Advances, 6 (77): 73148-73155. doi: 10.1039/C6RA15520K Li B, Ma X, Zhang G, et al. 2020. Enhancement of gas production from natural gas hydrate reservoir by reservoir stimulation with the stratification split grouting foam mortarmethod[J]. Journal of Natural Gas Science and Engineering, 81: 103473. doi: 10.1016/j.jngse.2020.103473 Li S D, Li X, Wang S J, et al. 2020. A novel method for natural gas hydrate production: Depressurization and backfilling with in-situ supplementalheat[J]. Journal of Engineering Geology, 28 (2): 282-293. Li S D, Sun Y M, Chen W C, et al. 2019. Analyses of gas production methods and offshore production tests of natural gashydrates[J]. Journal of Engineering Geology, 27 (1): 55-68. http://en.cnki.com.cn/Article_en/CJFDTotal-GCDZ201901007.htm Li X D, Li G H, Wei J S, et al. 2018. Evaluating the effect of delayed gel breaking by P(Vac-AA)core-shell microsphere fracturing fluid gelbreaker[J]. Drilling Fluid & Completion Fluid, 35 (6): 122-125. http://www.researchgate.net/publication/332710392_Evaluating_the_Effect_of_Delayed_Gel_Breaking_by_PVac-AA_Core-Shell_Microsphere_Fracturing_Fluid_Gel_Breaker Liu X, Zhang W, Qu Z, et al. 2020. Feasibility evaluation of hydraulic fracturing in hydrate-bearing sediments based on analytic hierarchy process-entropy method(AHP-EM)[J]. Journal of Natural Gas Science and Engineering, 81: 103434. doi: 10.1016/j.jngse.2020.103434 Long X F, Dai L, Lou B, et al. 2017. The kinetics research of thermochemical energy storage system Ca(OH)2/CaO[J]. International Journal of Energy Research, 41(7): 1004-1013. doi: 10.1002/er.3688 Masuda Y, Fujinaga Y, Naganawa S. 1999. Modeling and experimental studies on dissociation of methane gas hydrates in Berea sandstone cores[C]//The 3rd International Conference on GasHydrates. Salt Lake City, Utah: [s. n. ]. Moridis G J, Reagan M T, Queiruga A F, et al. 2019. Evaluation of the performance of the oceanic hydrate accumulation at site NGHP-02-09 in the Krishna-Godavari Basin during a production test and during single and multi-well productionscenarios[J]. Marine and Petroleum Geology, 108 : 660-696. doi: 10.1016/j.marpetgeo.2018.12.001 Moridis. 2014. User's manual for the hydrate v1.5 option of TOUGH+v1.5: A code for the simulation of system behavior in hydrate-bearing geologic media[R]. Berkeley, CA(United States): Lawrence Berkeley National Lab. (LBNL). Reagan M, Moridis G J, Reagan M T, et al. 2008. The use of horizontal wells in gas production from hydrate accumulations[C]//6th International Conference on Gas Hydrates. United State: [s. n. ]. Ruan X K, Li X S, Xu C G. 2020. A review of numerical research on gas production from natural gas hydrates inChina[J]. Journal of Natural Gas Science and Engineering, 85: 103713. http://www.sciencedirect.com/science/article/pii/S1875510020305679 Schaube F, Koch L, Wrner A, et al. 2012. A thermodynamic and kinetic study of the De-and rehydration of Ca(OH)2 at high H2O partial pressures for thermo-chemical heatstorage[J]. Thermochimica Acta, 538 : 9-20. doi: 10.1016/j.tca.2012.03.003 Shan L, Fu C, Liu Y, et al. 2020. A feasibility study of using frac-packed wells to produce natural gas from subsea gas hydrateresources[J]. Energy Science & Engineering, 8 (4): 1247-1259. doi: 10.1002/ese3.590 Shen P F, Li G, Li X S, et al. 2021. Application of fracturing technology to increase gas production in Low-permeability hydrate reservoir: A numericalstudy[J]. Chinese Journal of Chemical Engineering, 34 : 267-277. doi: 10.1016/j.cjche.2020.07.019 Sun J X, Ning F L, Liu T L, et al. 2019. Gas production from a silty hydrate reservoir in the South China Sea using hydraulic fracturing: A numericalsimulation[J]. Energy Science & Engineering, 7 (4): 1106-1122. Sun Y M, Li S D, Lu C, et al. 2021. The characteristics and its implications of hydraulic fracturing on hydrate-bearing clayey silt[J]. Journal of Natural Gas Science and Engineering, 95: 104189. doi: 10.1016/j.jngse.2021.104189 Van Genuchten M T. 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils[J]. Soil Science Society of America Journal, 44 (5): 892-898. doi: 10.2136/sssaj1980.03615995004400050002x Wu N Y, Li Y L, Wan Y Z, et al. 2020. Prospect of marine natural gas hydrate stimulation theory and technologysystem[J]. Natural Gas Industry, 40 (8): 100-115. http://www.sciencedirect.com/science/article/pii/S2352854021000243 Yang L, Chen C, Jia R, et al. 2018. Influence of reservoir stimulation on marine gas hydrate conversion efficiency in different accumulation conditions[J]. Energies, 11(2): 339. doi: 10.3390/en11020339 Yang L, Shi F K, Zhang X H, et al. 2020. Experimental studies on the propagation characteristics of hydraulic fracture in clay hydratesediment[J]. Chinese Journal of Theoretical and Applied Mechanics, 52 (1): 224-234. Ye J L, Qin X W, Xie W W, et al. 2020. Main progress of the second gas hydrate trial production in the South ChinaSea[J]. Geology in China, 47 (3): 557-568. Zhao E, Hou J, Liu Y, et al. 2020. Enhanced gas production by forming artificial impermeable barriers from unconfined hydrate deposits in Shenhu area of South ChinaSea[J]. Energy, 213: 118826. doi: 10.1016/j.energy.2020.118826 李守定, 李晓, 王思敬, 等. 2020. 天然气水合物原位补热降压充填开采方法[J]. 工程地质学报, 28 (2): 282-293. doi: 10.13544/j.cnki.jeg.2020-061 李守定, 孙一鸣, 陈卫昌, 等. 2019. 天然气水合物开采方法及海域试采分析[J]. 工程地质学报, 27 (1): 55-68. doi: 10.13544/j.cnki.jeg.2019-065 李晓丹, 李光辉, 未九森, 等. 2018. P(Vac-AM)核壳微球型压裂液破胶剂延迟破胶效果评价[J]. 钻井液与完井液, 35 (6): 122-125. https://www.cnki.com.cn/Article/CJFDTOTAL-ZJYW201806022.htm 吴能友, 李彦龙, 万义钊, 等, 2020. 海域天然气水合物开采增产理论与技术体系展望[J]. 天然气工业, 40 (8): 100-115. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG202008013.htm 杨柳, 石富坤, 张旭辉, 等. 2020. 含水合物粉质黏土压裂成缝特征实验研究[J]. 力学学报, 52 (1): 224-234. https://www.cnki.com.cn/Article/CJFDTOTAL-LXXB202001020.htm 叶建良, 秦绪文, 谢文卫, 等. 2020. 中国南海天然气水合物第二次试采主要进展[J]. 中国地质, 47 (3): 557-568. https://www.cnki.com.cn/Article/CJFDTOTAL-DIZI202003002.htm -
点击查看大图
计量
- 文章访问数: 164
- HTML全文浏览量: 30
- PDF下载量: 34
- 被引次数: 0
