Abstract
Transport of emulsions in porous media is relevant to several subsurface applications. Many enhanced oil recovery (EOR) processes lead to emulsion formation and as a result conformance originating in the flow of a dispersed phase may arise. In some EOR processes, emulsion is injected directly as a mobility control agent. Modeling the flow of emulsion in porous media is extremely challenging due to the complex nature of the associated flows and numerous interfaces. The descriptions based on effective viscosity are not valid when the drop size is of the same order of magnitude as the pore-throat characteristic length scale. An accurate model of emulsion flow through porous media should describe this local change in mobility. The available filtration models do not take into account the variation of the straining and capturing rates with the local capillary number. In this work, we present experiments of emulsion flow through sandstone cores of different permeability and a first step on a capillary network model that uses experimentally determined pore-level constitutive relationships between flow rate and pressure drop in constricted capillaries to obtain representative macroscopic flow behavior emerging from microscopic emulsion flow at the pore level. A parametric analysis is conducted to study the effect of the permeability and dispersed phase droplet size on the flow response to emulsion flooding in porous media. The network model predictions qualitatively describe the oil-water emulsion flow behavior observed in the experiments.
Highlights
Oil-water emulsion injection has been found to play an important role in enhanced-oil recovery (EOR) processes
McAuliffe [2] compared water flooding to a dilute emulsion flooding. They observed a delay in the water breakthrough time, indicating a more uniform sweep, and an increase in the volume of oil produced in the case of emulsion flooding
Similar improvement in sweep efficiency and volume of oil recovery observed in other EOR processes, such as alkalinesurfactant [6,7,8] and alkaline-surfactant-polymer [9] flooding, can be explained by the action of emulsion flow at the pore scale
Summary
Oil-water emulsion injection has been found to play an important role in enhanced-oil recovery (EOR) processes. Similar improvement in sweep efficiency and volume of oil recovery observed in other EOR processes, such as alkalinesurfactant [6,7,8] and alkaline-surfactant-polymer [9] flooding, can be explained by the action of emulsion flow at the pore scale. Several experimental analyses of flow of emulsion through porous media have shown that oil drops of the emulsion can block pore throats, which in turn leads to local permeability reduction [1,14,15]. The experiments consisted of injecting oil-water emulsion with known drop size distribution through sandstone cores with two different permeability values to analyze the effect of drop to pore throat diameter ratio on the steady state pressure drop−flow rate relationship.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have