Suspension Flow in Petroleum Reservoirs: Fractional Flow Theory

Abstract

AbstractTransport of particle suspensions in oil reservoirs occurs during sea- or produced water injection with particle capture and consequent injectivity decline, produced water disposal in aquifers and subterranean water contamination, drilling fluid invasion causing formation damage, fines migration during production of heavy oils in low consolidated reservoirs resulting in productivity decline and during sand production control by gravel packs and sand screens.Previous studies derive micro- and macro scale equations for deep bed filtration in rocks. A finite size particle cannot enter smaller pore; it also cannot approach the wall of the larger pore closer that its radius. Therefore, mono dispersed suspension and clean water move in separate parts of porous space, and have different viscosities and densities. The suspension "saturation" is so-called accessibility factor. Relative permeabilities for each "phase" in modified Darcy's law depend on saturation and on deposited particle concentration. It closes system of equations for mono dispersed suspension transport in porous media. Finally, so-called flux reduction factor turned to be the fractional flow function. The closed macro scale system has fractional flow type. The developed model significantly differs from the classical filtration model.In the current work, the laboratory data on injectivity impairment with suspension coreflood were treated. The model exhibits good agreement with experimental data.