Characterisation of Formation Damage Systems from Laboratory Coreflood Pressure Measurements

Abstract

Abstract During reactive flows in porous media with precipitation of a solid chemical reaction product, the permeability reduction occurs. The mathematical model for reactive flow in porous media formulated contains two empirical parameters – the kinetics rate coefficient, determining the reaction rate along with reagent's concentrations, and the formation damage coefficient, reflecting the permeability reduction due to the solid precipitation. These parameters are determined from the laboratory coreflood tests with commingled injection of reacting fluids. A routine laboratory method determines the kinetics rate coefficient from expensive and cumbersome reagent concentration at the core effluent; then, the formation damage coefficient is calculated from inexpensive and simple pressure drop measurements. In the current paper, a laboratory method for determining both coefficients from pressure measurements only is developed. The method utilises pressure measurements at the core inlet, effluent and some intermediate core port during commingled quasi steady state flow of incompatible fluids. The data treatment is based on the analytical model for one-dimensional commingled flow of reacting fluids. The formulae for determining the model coefficients from pressure measurements are derived. The intervals for inverse solution existence, uniqueness and stability are established. Good agreement between the model constants as determined by the routine and three-point-pressure methods validates the proposed method.