摘要
为研究多重流动机制各向异性对页岩气运移的影响,基于Biot线弹性孔隙介质模型,考虑黏性流动、气体流动动态效应和表面吸附扩散等流动机制的各向异性,采用各向同性应力依赖模型,建立流-固耦合的视渗透率模型,对应力约束边界条件下的页岩气运移过程进行数值模拟,定量分析流动各向异性对页岩气运移的影响。结果表明各种流动机制的各向异性均对页岩气运移有显著影响:固有渗透率各向异性可明显改变页岩气运移开始时间和流通量大小,其影响随页岩储层渗透率增加而放大;当固有渗透率较小时,动态效应各向异性会削弱气体流动的动态效应,对页岩气运移开始时间和流通量的影响十分显著,但在固有渗透率较大时其影响可以忽略;表面吸附扩散各向异性的影响与固有渗透率各向异性相似。准确评估页岩气的运移能力和产能应考虑运移过程中的流动各向异性。
Based on Biot’s model of linear elastic porous medium,taking into account for the anisotropy of flow mechanisms such as viscous flow,dynamic effects of gas flow and surface adsorptive diffusion,and adopting the isotropic stress dependence model,a fluid-solid coupling apparent permeability model was established to investigate the effect of anisotropy of multiple flow mechanisms on shale gas transport.Numerical simulation on the shale gas migration process under the stress constraint boundary conditions was then conducted to quantitatively analyze the influence of flow anisotropy on shale gas transfer.The results show that the anisotropy of each flow mechanism has significant impact on shale gas transport.The anisotropy of intrinsic permeability can give rise to remarkable changes on the beginning of shale gas transfer and the gas flux,and such influence is enhanced by increasing the shale permeability.The anisotropy of dynamic effects can diminish the dynamic effects of gas flow and has a significant influence on the beginning of shale gas transfer and the gas flux when the intrinsic permeability is low.While the influence can be neglected in the case of large intrinsic permeability.The effect of anisotropy of surface adsorptive diffusion is similar to that of intrinsic permeability anisotropy.Therefore,it is necessary to consider the flow anisotropy in the migration process when accurately evaluating the migration ability and productivity of shale gas.
作者
赵静
古斌
ZHAO Jing;GU Bin(School of Manufacturing Science and Engineering,Southwest University of Science and Technology,Mianyang 621010,Sichuan,China;Key Laboratory of Testing Technology for Manufacturing Process,Ministry of Education,Southwest University of Science and Technology,Mianyang 621010,Sichuan,China)
出处
《西南科技大学学报》
CAS
2023年第1期40-46,共7页
Journal of Southwest University of Science and Technology
基金
国家自然科学基金面上项目(11872324)。
关键词
页岩气运移
多重流动机制
流动各向异性
视渗透率模型
数值模拟
Shale gas migration
Multiple flow mechanisms
Flow anisotropy
Apparent permeability model
Numerical simulation
