Oilfield Scaling – Part I: Mathematical and Laboratory Modelling

Abstract

The BaSO4 scaling is a chronicle disaster in waterflood projects with incompatible injected and formation waters. This is usually due to precipitation of barium sulphate from the mixture of both waters and consequent permeability reduction. The effect of porous media on the BaSO4 scaling kinetics is studied. A new methodology for determination of kinetic constant from coreflood tests consists of the sequence of diffusivity tests, of transient tests with chemical reaction, and of steady state tests on simultaneous injection of both injected and formation waters. The diffusion coefficient versus flow velocity is found from the diffusivity tests. Steady state tests allow determination of chemical reaction rate constant versus velocity. The transient test data as compared with the mathematical modelling data validates the results of steady state tests treatment. The test data are treated using semi-analytical and numerical models. The main result of the work is the proportionality between the chemical reaction constant and flow velocity in the range studied.