Oxygen transport in a matrix–fracture system under reactive conditions at pore-scale

• We modelled oxygen transport in a matrix fracture system at pore-scale.
• We studied the effect of oxygen flow rate, fracture width and reaction rate.
• Increasing oxygen flow rate and reaction rate favours the coke consumption.
• As fracture width is larger more oxygen is transported to matrix.

In this work, the oxygen transport in a nitrogen saturated matrix–fracture system at pore-scale was modelled. The microstructure of the porous matrix was modelled as a medium composed of circular particles periodically arranged. We considered the oxygen–coke reaction on the particle surface in order to simulate the combustion reaction encountered in an in-situ combustion process. The gas, coke and oxygen mass balances, and the gas momentum balance (assuming Newtonian fluid) were solved using a finite element solver. The oxygen distribution, in the matrix–fracture system, was studied in terms of the oxygen flow rate, fracture width and combustion reaction rate. It was found that increasing the oxygen flow rate, fracture width and combustion reaction rate favours the coke consumption. Moreover, these parameters increase the oxygen transport from the fracture to the porous zone.