论文部分内容阅读
利用四川大学THMC岩石三轴试验系统,针对中国天然气储库杂质盐岩开展全过程渗透试验研究,并通过试验结果拟合出同时考虑围压、扩容体积应变以及杂质含量的多因素耦合杂质盐岩渗透模型。研究表明:杂质含量、杂质分布及成分对盐岩渗透性均有显著影响,不同杂质含量盐岩损伤恢复后渗透率均有所降低,其塑性变形可分为2个阶段,I阶段渗透率增长迅速,II阶段渗透率增速减缓甚至渗透率下降,盐岩破坏后渗透率明显增大,残余阶段能维持在相对稳定的水平;低渗夹层制约盐岩垂向渗透性,而泥质成分盐岩较钙芒硝质盐岩渗透率更低。由拟合的多因素耦合渗透模型可得到:围压越高渗透率越低,扩容体积应变越大渗透率越高。当杂质含量大于0.46时,渗透率随杂质含量的增大而增大,当杂质含量小于0.46时,渗透率随杂质含量的增大而减小。
Through the THMC rock triaxial test system of Sichuan University, the whole process of infiltration test is carried out for the salt rock of natural gas reservoir in China. Based on the experimental results, the multi-factor coupled impurity salt rock considering the confining pressure, volume expansion and volume strain and impurity content Penetration model. The results show that the impurity content, impurity distribution and composition have a significant effect on the permeability of salt rock. The permeability of salt rock with different impurity content is reduced after the damage, and the plastic deformation can be divided into two stages, the permeability of stage I increases Rapidly, the permeability of II phase slowed down or even decreased. After salt rock failure, the permeability increased obviously and the residual phase could be maintained at a relatively stable level. The low permeability sandstone restricted the vertical permeability of salt rock, while the shale salt rock Permeability than Glauber’s salt rocks is lower. From the fitted multi-factor coupled seepage model, the higher the confining pressure is, the lower the permeability is, and the larger the volumetric strain is, the higher the permeability is. When the impurity content is more than 0.46, the permeability increases with the increase of impurity content. When the impurity content is less than 0.46, the permeability decreases with the increase of impurity content.