A numerical procedure for the evaluation of equivalent permeability tensor for fractured vuggy porous media is presented.At first we proposed a new conceptual model,i.e.,discrete fracture-vug network model,to model th...A numerical procedure for the evaluation of equivalent permeability tensor for fractured vuggy porous media is presented.At first we proposed a new conceptual model,i.e.,discrete fracture-vug network model,to model the realistic fluid flow in fractured vuggy porous medium on fine scale.This new model consists of three systems:rock matrix system,fractures system,and vugs system.The fractures and vugs are embedded in porous rock,and the isolated vugs could be connected via discrete fracture network.The flow in porous rock and fractures follows Darcy’s law,and the vugs system is free fluid region.Based on two-scale homogenization theory,we obtained an equivalent macroscopic Darcy’s law on coarse scale from fine-scale discrete fracture-vug network model.A finite element numerical formulation for homogenization equations is developed.The method is verified through application to a periodic model problem and then is applied to the calculation of equivalent permeability tensor of porous media with complex fracture-vug networks.The applicability and validity of the method for these more general fractured vuggy systems are assessed through a simple test of the coarse-scale model.展开更多
During the long-time operation of salt rock storage cavern,between its formations,damaged interfaces induced by discontinuous creep deformations between adjacent layers will possibly lead to serious gas leakage.In thi...During the long-time operation of salt rock storage cavern,between its formations,damaged interfaces induced by discontinuous creep deformations between adjacent layers will possibly lead to serious gas leakage.In this paper,damaged interfaces are considered as main potential leakage path:firstly in meso-level,gas flow rule along the interface is analyzed and the calculation of equivalent permeability is discussed.Then based on porous media seepage theory,gas leakage simulation model including salt rock,cavity interlayers and interface is built.With this strategy,it is possible to overcome the disadvantage of simulation burden with porous-fractured double medium.It also can provide the details of gas flowing along the damaged zones.Finally this proposal is applied to the salt cavern in Qianjian mines(East China).Under different operation pressures,gas distributions around two adjacent cavities are simulated;the evolvement of gas in the interlayers and salt rock is compared.From the results it is demonstrated that the domain of creep damage area has great influence on leakage range.And also the leakage in the interface will accelerate the development of leakage in salt rock.It is concluded that compared with observations,this new strategy provides closer answers.The simulation result proves its validity for the design and reasonable control of operating pressure and tightness evaluation of group bedded salt rock storage caverns.展开更多
文摘A numerical procedure for the evaluation of equivalent permeability tensor for fractured vuggy porous media is presented.At first we proposed a new conceptual model,i.e.,discrete fracture-vug network model,to model the realistic fluid flow in fractured vuggy porous medium on fine scale.This new model consists of three systems:rock matrix system,fractures system,and vugs system.The fractures and vugs are embedded in porous rock,and the isolated vugs could be connected via discrete fracture network.The flow in porous rock and fractures follows Darcy’s law,and the vugs system is free fluid region.Based on two-scale homogenization theory,we obtained an equivalent macroscopic Darcy’s law on coarse scale from fine-scale discrete fracture-vug network model.A finite element numerical formulation for homogenization equations is developed.The method is verified through application to a periodic model problem and then is applied to the calculation of equivalent permeability tensor of porous media with complex fracture-vug networks.The applicability and validity of the method for these more general fractured vuggy systems are assessed through a simple test of the coarse-scale model.
基金We acknowledge the following funds to give financial supports.They are China National Program on National natural sciences foundation of China Grant no.51104108 and 41172284,Key Basic Research Project(973 Program)Grant no.2009CB724603.
文摘During the long-time operation of salt rock storage cavern,between its formations,damaged interfaces induced by discontinuous creep deformations between adjacent layers will possibly lead to serious gas leakage.In this paper,damaged interfaces are considered as main potential leakage path:firstly in meso-level,gas flow rule along the interface is analyzed and the calculation of equivalent permeability is discussed.Then based on porous media seepage theory,gas leakage simulation model including salt rock,cavity interlayers and interface is built.With this strategy,it is possible to overcome the disadvantage of simulation burden with porous-fractured double medium.It also can provide the details of gas flowing along the damaged zones.Finally this proposal is applied to the salt cavern in Qianjian mines(East China).Under different operation pressures,gas distributions around two adjacent cavities are simulated;the evolvement of gas in the interlayers and salt rock is compared.From the results it is demonstrated that the domain of creep damage area has great influence on leakage range.And also the leakage in the interface will accelerate the development of leakage in salt rock.It is concluded that compared with observations,this new strategy provides closer answers.The simulation result proves its validity for the design and reasonable control of operating pressure and tightness evaluation of group bedded salt rock storage caverns.
