The kinetics of colloidal deposits in porous media

Colloidal fluids are very common in natural and industrial systems. In particular, they are present at different stages in the petroleum system. Generated in situ, or added for production purposes, they lead to significant reductions in permeability and alter the flow properties of fluids. Controlling the behavior of these systems in porous media is therefore a major challenge for the oil industry and is an integral component of Improved Oil Recovery (IOR).

Lahcen Nabzar Expert Flow in Porous media lahcen.nabzar@ifpen.fr

The process adopted by IFPEN is based on the “colloidal” approach, combined with a dimensional analysis. This strategy has led to identification of deposit regimes and determination of kinetic laws for these, such as scale laws, with exponents that are universal and system independent since they are dictated by the colloidal character common to colloids. Hence, in a convection/diffusion regime, deposits take place within a diffusion layer δ_D according to a first-order reaction with a constant k.

The kinetic law of the deposit is therefore expressed as follows:

With two adimensional numbers:

D_a: Damkohler (reaction/diffusion) and
P_eg: Peclet grain (convection/diffusion)
where Γ: density of the deposit (mg/m²),
U: fluid speed,
dg: grain size
and D∞: diffusion coefficient.

Two limit regimes can be distinguished:

The figure illustrates the validity of this law for solids and emulsions in the DLD regime (s~0.66).

Hence, this colloidal approach combined with adimensional analysis enables development of a unified vision, using adimensional numbers to model the deposit kinetics of colloids in porous media.

Deposit kinetics for different colloids.

Publications

• L. Nabzar and M.E. Aguiléra, OGST- Rev. IFP Energies nouvelles, Vol. 63 (2008), 21-35. DOI: 10.251/ogst/2007083

• S. Buret, L. Nabzar, and A. Jada, SPE J., 15 (2), June 2010: 557-568. DOI: 10.2118/122060-PA

>> See also IFPEN Publications database