Published 12 issues per year
ISSN Print: 1091-028X
ISSN Online: 1934-0508
Indexed in
SEQUENTIALLY COUPLED MODEL FOR MULTIPHASE FLOW, MEAN STRESS, AND REACTIVE SOLUTE TRANSPORT WITH KINETIC CHEMICAL REACTIONS: APPLICATIONS IN CO2 GEOLOGICAL SEQUESTRATION
ABSTRACT
The significance of thermal-hydrological-mechanical-chemical (THMC) interactions is well identified during the operation of CO2 geosequestration. Geomechanical and geochemical effects may significantly affect aqueous phase composition, porosity, and permeability of the formation, which in turn influence flow and transport. A mean stress formulation is proposed to represent the geomechanical effects such as stresses, displacements, and rock deformation. The geochemistry is described mathematically under equilibrium and kinetic conditions. Based on these theories, a sequentially coupled computational framework is proposed and used to simulate reactive transport of water, supercritical CO2, and species in subsurface formation with geomechanics. A practical reactive transport example with complex chemical compositions is presented to analyze the THMC processes quantitatively on the coupled effects of geochemical reaction and geomechanics for CO2 geosequestration. The results indicate that the THMC coupling effects are not obvious during CO2 sequestration. The geomechanical effect dominates the early period of CO2 injection, and the geochemical reaction dominates the long-term fate of CO2. The efficacy of mineral trapping of supercritical CO2 with respect to 30% plagioclase feldspar minerals in a sandstone reservoir increases to 65% after 10,000 years.