| Can Emulsions Show Better Placement Properties than Gelants When Used as Blocking Agents? (No.) |
| Analysis of the literature (Refs. 70-103 in Ref. 13) suggests no reason to believe that emulsions have any placement or permeability-reduction advantages over gelants and gels.13 For concentrated emulsions (either oil-in-water or water-in-oil), their behavior in porous media can be described using standard relative-permeability concepts.92-93 Therefore, the placement properties of concentrated emulsions are similar to those of viscous gelants.18 Also, the literature indicates that concentrated emulsions provide very low permeability-reduction values (residual resistance factors less than 1.5).13,92,93 Furthermore, residual resistance factors provided by concentrated emulsions do not increase with increasing initial rock permeability.92,93 |
| Dilute emulsions show behavior that can be described by a modified deep-bed filtration theory.94-96 Ref. 13 contains a detailed examination of the literature and models that describe the flow of dilute emulsions through porous media. We can summarize the results of this analysis as follows: although several features of emulsion flow through porous media remain unanswered, our analysis of the literature indicates that emulsions or emulsion/gel combinations will not perform significantly better than gels as blocking agents, particularly in the areas of placement characteristics and permeability-reduction properties. Our calculations indicate that at best, the placement properties of emulsions will approach those for a low-viscosity gelant. |