Flow of Oil-in-Water Emulsions Through Tubes and Porous Media
Authors: Alvarado D.A. , Marsden S.S. 
Published: December 2007

The flow of oil-in-water macroemulsions through both porous media and capillary tubes has been studied experimentally and described mathematically. Macroemulsions are those emulsions with most of their droplet diameters greater than I AM, which is the same order of magnitude as the pore constrictions.

The emulsions were pumped with a positive displacement pump through several porous media and capillary tubes connected in series.

The rheological behavior of macroemulsions with oil concentrations ranging from 10 to 70 vol% was obtained using capillary tube data. Emulsions with oil concentrations less than 50% behaved like Newtonian fluids, white those with concentrations greater than 50% behaved like pseudoplastic fluids. Viscoelastic effects were not observed for these fluids.

A correlation, which uses both capillary and core flow data, was developed for describing the flow of non-Newtonian macroemulsions through porous media. This led to a general equation that reduced to Darcy's law for Newtonian fluids. The average relative error found when applying the method of correlation was +/- 4 %.

Introduction

The subject of emulsions is a broad field that includes many instances of application in industry. We are interested mainly in one specific area of application here - the oil industry. The study of emulsions has received considerable attention in petroleum research laboratories during the past 15 petroleum research laboratories during the past 15 years. The development of new methods of secondary recovery and the potential application of crude oil transportation through pipelines as stable emulsions have increased the number of research programs dealing with emulsions. programs dealing with emulsions. Macroemulsions, or ordinary emulsions, are dispersions of one liquid within another liquid. third component in an emulsion is the emulsifying agent or emulsifier, which has two principal functions:to decrease the interfacial tension between the liquids, thereby enabling easier formation of the greatly extended interface, andto stabilize the dispersed phase against coalescence once it is formed. With water or brine as one of the liquids, two types of emulsions are possible - oil-in-water (O/W) and water-in-oil (W/O) emulsions.

Note that most of worlds's crude oil is produced in emulsion form. These emulsions are generally water-in-crude oil emulsions, which are more viscous than either of their constituents. Since we are interested only in maximum economical oil production, it is a common practice to separate emulsions production, it is a common practice to separate emulsions into their components, thereby obtaining reduced viscosity. This is accomplished in the oil field by using chemical and heat treatments. In contrast to W/O emulsions, O/W emulsions have lower viscosities than their oil constituent. This was considered by some investigators during the development of systems for producing and transporting crude oil as O/W emulsions.

During the last decade or so, a number of new secondary oil recovery processes have been developed. These methods include the use of high-viscosity emulsions to displace oil, the use of emulsion slugs between the displacing fluid (water) and the displaced fluid (Oil), and controlled viscosity microemulsions. We see that, for an engineer to describe properly the flow behavior of emulsions in both pipelines and reservoirs, he must know the properties of emulsions and the physical laws properties of emulsions and the physical laws controlling their flow through tubes and porous media.

The purpose of this research was to study the flow of O/W macroemulsions through both porous media and capillary tubes. The rheological characteristics of emulsions were analyzed by using capillary viscometers.

SPEJ

P. 369