Slow migration of mobilised fines during flow in reservoir rocks: Laboratory study

Permeability decline during high rate flows has been widely reported for corefloods and for production wells. The phenomenon is attributed to mobilisation of fine particles at elevated velocities, their migration in porous space with the following straining in thin pores and attachment to pore walls. Sixteen sets of corefloods with piecewise constant rate have been performed under increasing flow rate. The particularities of this study are long injection periods, allowing estimating permeability stabilisation times, and pressure measurements in intermediate core points, permitting for evaluation of the permeability profile variation along the core. It was found out that the mobilised particles drift with speeds significantly lower than the carrier fluid velocity, resulting in long permeability stabilisation periods.