Hydraulic crack propagation and rock permeability under osmotic pressure gradients with implications for deep CO₂ sequestration and fraccing

Long-term deep sequestration of CO₂-rich brine in deep formations of ultramafic rock (e.g.Oman serpentinized harzburgite) will be feasible only if a network of hydraulic cracks could be produced and made to grow for years and decades.Fraccing of gas- or oil-bearing shales has a similar objective.The following points are planned to be made in the presentation in Golden.1) A branching of fracture can be analyzed only if the fracture is modeled by a band with triaxial tensorial damage, for which the new smooth Lagrangian crack band model is effective.2) To achieve a progressive growth of the fracture network one will need to manipulate the osmotic pressure gradients by changing alkali metal ion concentration in pore fluid.3) A standardized experimental framework to measure rock permeability at various ion concentrations and various osmotic pressure gradients is needed, and will be presented.