Investigation on gas migration in saturated materials with low permeability

摘要: Investigation of the hydro-mechanical effects on gas migration in saturated materials with low permeability is great theoretical and practical significances many engineering fields. The conventional two-phase flow (visco-capillary flow) theory, which regards capillary pressure as only controlling factor gas migration processes, is commonly adopted to describe flow geo-materials. However, formaterials with lowpermeability, two-phase theory cannot properly gasmigration. In this work, coupled injection tests were conducted. volumetric variation the liquid for applying confining specimen cell rate monitored. Test results indicate that influenced by mechanical stress simultaneously. The two key parameters entry Pentry induced-dilatancy pressure Pdilatancy are introduced description respect mechanical stress effects, respectively. When smaller than the Pdilatancy, balance between will lead an intermittent gas flow. Sudden increase could be observed once approaches the or Pdilatancy. For higher pressures, migration could not neglected. sudden flux under high pressures caused by channels, induced-continuous pathways, as well failure sealing-efficiency. sealing-efficiency closely related difference between rather properties material tested. Monitoring volume liquid helpful detecting failure of sealing efficiency mechanism breakthrough.