Action of Fluid Loss Agents

Reduced fluid loss is achieved by plugging a porous rock in some way. The basic mechanisms are shown in Table 2-1. 

A monograph concerning the mechanism of invasion of particles into the formation is given by Chin [375]. 

The hydrodynamic forces acting on the suspended colloids determine the rate of cake buildup and therefore the fluid loss rate. A simple model has been proposed in literature [907] that predicts a power law relationship between the filtration rate and the shear stress at the cake surface. The model shows that the cake formed will be inhomogeneous with smaller and smaller particles being deposited as the filtration proceeds. An equilibrium cake thickness is achieved when no particles small enough to be deposited are available in the suspension. The cake thickness as a function of time can be computed from the model. 

Macroscopic particles Microscopic particles Chemical grouting 

Suspended particles may clog the pores, forming a filter-cake with reduced permeability. 

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