页岩油藏多重孔隙介质耦合流动数值模拟
|
摘要
页岩孔隙类型多样,微纳米尺度孔隙发育,借助分段压裂水平井技术能够实商业化开采。原油分子与孔隙壁面作用较甲烷分子更加复杂,目前页岩油在无机和有机纳米孔中的运移机制尚不清楚。准确模拟页岩油微观运移机制和多重孔隙介质间耦合流动对页岩油藏产能评价和生产预测具有重要意义。结合润湿特性,考虑液体吸附、速度滑移及物性变化等机制,引入复杂结构参数(迂曲度、孔隙度和有机孔含量),建立了微纳米多孔介质液体表观渗透率模型,研究了不同运移机制对微纳米多孔介质表观渗透率影响。在此基础上,建立了基质-天然裂缝-人工裂缝耦合的页岩油藏分段压裂水平井数学模型,利用有限元方法求解,进行产能影响因素分析。结果表明,孔隙半径小于10 nm时,微纳米孔隙速度滑移影响明显,而孔隙半径大于100 nm时,微观运移机制作用可以忽略;有机孔隙含量越小、裂缝条数越多则分段压裂水平井产能越大;最优的缝网模式为缝网无间距且不重叠。本研究的重点是丰富微纳米孔隙内油气运移理论,为页岩油藏开发模拟研究提供理论方法。
Shale reservoirs are characterized by various pores with micro-and nano-pores well developed. Commercial shale oil development can be achieved by means of staged fracturing in horizontal wells. The interaction between oil molecules and pore wall is more complex than that between methane molecules and pore wall,but it is still unclear about the migration mechanism of shale oil in inorganic and organic nano-pores at present. Accurate simulation of the microscopic migration mechanisms of shale oil and the coupled flow in multi-pore media is of great significance to productivity evaluation and production prediction in shale oil reservoirs. Considering wettability and mechanisms of liquid adsorption,velocity slip and physical property change,we established the apparent permeability model for fluids in micro-and nano-scale multi-pore media based on the complex structural parameters( including tortuosity,porosity and organic pore content),to explore the effects of different migration mechanisms on the apparent permeability of micro-and nano-scale multi-pore media. Subsequently,the mathematical model with matrix,natural fracture and artificial fracture coupled was set up for multistage fractured horizontal wells in shale oil reservoirs. Besides,the finite element method was used to solve the model,and to analyze the factors affecting productivity. The results show that when the pore radius is less than 10 nm,the effect of velocity slip in micro-and nano-pores is significant,while when the pore radius is greater than 100 nm,the effect of microscopic migration mechanisms may be neglected. The less the number of organic pores and the more the number of fractures,the greater the productivity of multistage fractured horizontal wells will be. The optimal fracture network is that has neither spacing nor overlapping between the adjacent fractures. The highlight of the study is to enrich the theories on oil and gas migration in micro-and nano-pores,so as to contribute to the development simulation of shale reservoirs with theoretical methods.
Shale reservoirs are characterized by various pores with micro-and nano-pores well developed. Commercial shale oil development can be achieved by means of staged fracturing in horizontal wells. The interaction between oil molecules and pore wall is more complex than that between methane molecules and pore wall,but it is still unclear about the migration mechanism of shale oil in inorganic and organic nano-pores at present. Accurate simulation of the microscopic migration mechanisms of shale oil and the coupled flow in multi-pore media is of great significance to productivity evaluation and production prediction in shale oil reservoirs. Considering wettability and mechanisms of liquid adsorption,velocity slip and physical property change,we established the apparent permeability model for fluids in micro-and nano-scale multi-pore media based on the complex structural parameters( including tortuosity,porosity and organic pore content),to explore the effects of different migration mechanisms on the apparent permeability of micro-and nano-scale multi-pore media. Subsequently,the mathematical model with matrix,natural fracture and artificial fracture coupled was set up for multistage fractured horizontal wells in shale oil reservoirs. Besides,the finite element method was used to solve the model,and to analyze the factors affecting productivity. The results show that when the pore radius is less than 10 nm,the effect of velocity slip in micro-and nano-pores is significant,while when the pore radius is greater than 100 nm,the effect of microscopic migration mechanisms may be neglected. The less the number of organic pores and the more the number of fractures,the greater the productivity of multistage fractured horizontal wells will be. The optimal fracture network is that has neither spacing nor overlapping between the adjacent fractures. The highlight of the study is to enrich the theories on oil and gas migration in micro-and nano-pores,so as to contribute to the development simulation of shale reservoirs with theoretical methods.
引文
[1]陈康,张金川,唐玄,等.湘鄂西地区下志留统龙马溪组页岩吸附能力主控因素[J].石油与天然气地质,2016,37(1):23-29.Chen Kang,Zhang Jinchuan,Tang Xuan. et al. Main controlling factors on shale adsorption capacity of the Lower Silurian Longmaxi Formation in western Hunan-Hubei area[J]. Oil&Gas Geology,2016,37(1):23-29.
[2]王民,关莹,李传明,等.济阳坳陷沙河街组湖相页岩储层孔隙定性描述及全孔径定量评价[J].石油与天然气地质,2018,39(6):1107-1119.Wang Min,Guan Ying,Li Chuanming,et al. Qualitative description and ful pore size quantitative evaluation of pores in lacustrine shale reservoir of Shahejie Formation,Jiyang Depression[J]. Oil&Gas Geology,2018,39(6):1107-1119.
[3]李文浩,卢双舫,薛海涛,等.江汉盆地新沟嘴组页岩油储层物性发育主控因素[J].石油与天然气地质,2016,37(1):56-61.Li Wenhao,Lu Shuangfang,Xue Haitao,et al. Major controlling factors of poroperm characteristics of shale oil reservoirs in the Xingouzui Formation,Jianghan Basin[J]. Oil&Gas Geology,2016,37(1):56-61.
[4] Wang S,Javadpour F,Feng Q. Molecular dynamics simulations of oil transport through inorganic nanopores in shale[J]. Fuel,2016,171:74-86.
[5] Wang S,Javadpour F,Feng Q. Fast mass transport of oil and supercritical carbon dioxide through organic nanopores in shale[J]. Fuel,2016,181:741-58.
[6] Yan B,Alfi M,Wang Y,et al. A new approach for the simulation of fluid flow in unconventional reservoirs through multiple permeability modeling[C]//SPE Annual Technical Conference and Exhibition,New Orleans,LA:SPE; 2013.
[7] Wu K,Chen Z,Li X,et al. A model for multiple transport mechanisms through nanopores of shale gas reservoirs with real gas effectadsorption-mechanic coupling[J]. International Journal of Heat and Mass Transfer,2016,93:408-26.
[8]邹才能,朱如凯,吴松涛,等.常规与非常规油气聚集类型、特征、机理及展望———以中国致密油和致密气为例[J].石油学报,2012,33(2):173-187.Zou Caineng,Zhu Rukai,Wu Songtao,et al. Types,characteristics,genesis and prospects of conventional and unconventional hydrocarbon accumulations:taking tight oil and tight gas in China as an instance[J]. Acta Petrolei Sinica,2012,33(2):173-187.
[9] Ambrose R J,Hartman R C,Diaz Campos M,et al. New pore-scale considerations for shale gas in place calculations[C]//SPE Unconventional Gas Conference. Pittsburgh,PA:SPE,2010.
[10] Wu K,Chen Z,Li X,et al. Flow behavior of gas confined in nanoporous shale at high pressure:Real gas effect[J]. Fuel,2017,205:173-183.
[11] Wu K,Chen Z,Li X. Real gas transport through nanopores of varying cross-section type and shape in shale gas reservoirs[J]. Chemical Engineering Journal,2015,281:813-825.
[12] Mattia D,Calabro F. Explaining high flow rate of water in carbon nanotubes via solid-liquid molecular interactions[J]. Microfluidics&Nanofluidics,2012; 13:125-30.
[13] Wang S,Feng Q,Javadpour F,et al. Oil adsorption in shale nanopores and its effect on recoverable oil-in-place[J]. International Journal of Coal Geology,2015,147-148:9-24.
[14] Afsharpoor A,Javadpour F. Liquid slip flow in a network of shale noncircular nanopores[J]. Fuel,2016,180:580-90.
[15] Whitby M,Quirke N. Fluid flow in carbon nanotubes and nanopipes[J]. Nature Nanotechnology,2007,2(2):87-94.
[16] Barrat J,Bocquet Lydéric. Large slip effect at a nonwetting fluid-solid interface[J]. Physical Review Letters,1999,82(23):4671-4674.
[17] Falk K,Sedlmeier F,Joly L,et al. Ultralow liquid/solid friction in carbon nanotubes:comprehensive theory for alcohols,alkanes,OMCTS,and water[J]. Langmuir,2012,28(40):14261-72.
[18] Mattia D. Explaining high flow rate of water in carbon nanotubes via solid-liquid molecular interactions[J]. Microfluidics&Nanofluidics,2012,13(1):125-130.
[19] Cui J,Sang Q,Li Y. Liquid permeability of organic nanopores in shale:Calculation and analysis[J]. Fuel,2017,202:426-434.
[20] Wang S,Javadpour F,Feng Q. Fast mass transport of oil and supercritical carbon dioxide through organic nanopores in shale[J]. Fuel,2016,181:741-758.
[2]王民,关莹,李传明,等.济阳坳陷沙河街组湖相页岩储层孔隙定性描述及全孔径定量评价[J].石油与天然气地质,2018,39(6):1107-1119.Wang Min,Guan Ying,Li Chuanming,et al. Qualitative description and ful pore size quantitative evaluation of pores in lacustrine shale reservoir of Shahejie Formation,Jiyang Depression[J]. Oil&Gas Geology,2018,39(6):1107-1119.
[3]李文浩,卢双舫,薛海涛,等.江汉盆地新沟嘴组页岩油储层物性发育主控因素[J].石油与天然气地质,2016,37(1):56-61.Li Wenhao,Lu Shuangfang,Xue Haitao,et al. Major controlling factors of poroperm characteristics of shale oil reservoirs in the Xingouzui Formation,Jianghan Basin[J]. Oil&Gas Geology,2016,37(1):56-61.
[4] Wang S,Javadpour F,Feng Q. Molecular dynamics simulations of oil transport through inorganic nanopores in shale[J]. Fuel,2016,171:74-86.
[5] Wang S,Javadpour F,Feng Q. Fast mass transport of oil and supercritical carbon dioxide through organic nanopores in shale[J]. Fuel,2016,181:741-58.
[6] Yan B,Alfi M,Wang Y,et al. A new approach for the simulation of fluid flow in unconventional reservoirs through multiple permeability modeling[C]//SPE Annual Technical Conference and Exhibition,New Orleans,LA:SPE; 2013.
[7] Wu K,Chen Z,Li X,et al. A model for multiple transport mechanisms through nanopores of shale gas reservoirs with real gas effectadsorption-mechanic coupling[J]. International Journal of Heat and Mass Transfer,2016,93:408-26.
[8]邹才能,朱如凯,吴松涛,等.常规与非常规油气聚集类型、特征、机理及展望———以中国致密油和致密气为例[J].石油学报,2012,33(2):173-187.Zou Caineng,Zhu Rukai,Wu Songtao,et al. Types,characteristics,genesis and prospects of conventional and unconventional hydrocarbon accumulations:taking tight oil and tight gas in China as an instance[J]. Acta Petrolei Sinica,2012,33(2):173-187.
[9] Ambrose R J,Hartman R C,Diaz Campos M,et al. New pore-scale considerations for shale gas in place calculations[C]//SPE Unconventional Gas Conference. Pittsburgh,PA:SPE,2010.
[10] Wu K,Chen Z,Li X,et al. Flow behavior of gas confined in nanoporous shale at high pressure:Real gas effect[J]. Fuel,2017,205:173-183.
[11] Wu K,Chen Z,Li X. Real gas transport through nanopores of varying cross-section type and shape in shale gas reservoirs[J]. Chemical Engineering Journal,2015,281:813-825.
[12] Mattia D,Calabro F. Explaining high flow rate of water in carbon nanotubes via solid-liquid molecular interactions[J]. Microfluidics&Nanofluidics,2012; 13:125-30.
[13] Wang S,Feng Q,Javadpour F,et al. Oil adsorption in shale nanopores and its effect on recoverable oil-in-place[J]. International Journal of Coal Geology,2015,147-148:9-24.
[14] Afsharpoor A,Javadpour F. Liquid slip flow in a network of shale noncircular nanopores[J]. Fuel,2016,180:580-90.
[15] Whitby M,Quirke N. Fluid flow in carbon nanotubes and nanopipes[J]. Nature Nanotechnology,2007,2(2):87-94.
[16] Barrat J,Bocquet Lydéric. Large slip effect at a nonwetting fluid-solid interface[J]. Physical Review Letters,1999,82(23):4671-4674.
[17] Falk K,Sedlmeier F,Joly L,et al. Ultralow liquid/solid friction in carbon nanotubes:comprehensive theory for alcohols,alkanes,OMCTS,and water[J]. Langmuir,2012,28(40):14261-72.
[18] Mattia D. Explaining high flow rate of water in carbon nanotubes via solid-liquid molecular interactions[J]. Microfluidics&Nanofluidics,2012,13(1):125-130.
[19] Cui J,Sang Q,Li Y. Liquid permeability of organic nanopores in shale:Calculation and analysis[J]. Fuel,2017,202:426-434.
[20] Wang S,Javadpour F,Feng Q. Fast mass transport of oil and supercritical carbon dioxide through organic nanopores in shale[J]. Fuel,2016,181:741-758.