Page 268 - Reservoir Formation Damage

248 Reservoir Formation Damage

deposit over the similar wettability type pore surfaces. They can also
be captured at and detained behind the pore throats under favorable
conditions. The intermediately wet particles most likely move directly
towards the pore throats and are captured there under certain conditions,
because they migrate along the interface.

Surface Deposition

The volumetric rate of deposition of the particle species j from phase
J over a similar wetting pore surface can be expressed by (Civan, 1996):

= d = k djjjs(a.j (11-33)

subject to the initial condition

-jJS (11-34)

In Eq. 11-33, k djjjs is a deposition rate constant, a y is a stationary
deposition constant, 0 is a porosity, and f js is the fraction of the pore
surface of the same wettability type of the particle species j.
Similar to Gruesbeck and Collins (1982), Liu and Civan (1996) assumed
that the porosity variation by deposition of small amounts of particles is
negligible (i.e., (|) is a constant). Liu and Civan (1996) considered a
homogeneous wettability porous media, hence f js = 1, and neglected the
stationary deposition, therefore oc y =0.

Pore Throat Plugging

The volumetric rate of retention of particles in the pore space following
the pore throat plugging can be expressed by (Gruesbeck and Collins,
1982, Civan, 1996):

= d (11-35)

subject to the initial condition

(11-36)

Liu and Civan (1996) assumed the porosity change is negligible in
Eq. 11-35 (i.e., (}) = constant). In Eq. 11-35, k tiJtS denotes the rate