Surfactants surfactant-polymer systems

The present study investigates the adsorption and trapping of polymer molecules in flow experiments through unconsolidated oil field sands. Static tests on both oil sand and Ottawa sand indicates that mineralogy plays a major role in the observed behavior. Effect of a surfactant slug on polymer-rock interaction is also reported. Corroborative studies have also been conducted to study the anomalous pressure behavior and high tertiary oil recovery in surfactant dilute-polymer systems(ll,12). 

The earliest investigations of SPI in EOR were done by Trushenski and coworkers (1, 6). They reported that high mobility and phase separation can occur due to SPI. Szabo (7 ) studied several surfactant-polymer systems, and found that mixtures of sulfonates and polymer solutions separated into two or three phases. The above groups investigated aqueous solutions only, and the mechanism of interaction was not clearly defined. 

Most adsorption systems of practical importance contain strongly adsorbing species (multivalent cations and anions, surfactants, polymers). Systems without specific adsorption are difficult to realize even under laboratory conditions due to omnipresent strongly adsorbing impurities (cf. Chapter 3). On the other hand, the primary surface charging occurs also in more complex systems and it must be taken into account in modeling of specific adsorption. 

This paper presents observations on the difference in behavior of emulsification processes which can occur during surfactant and caustic flooding in enhanced recovery of petroleum. Cinephotomicrographic observations on emulsion characteristics generated at the California crude oil-alkaline solution interface as well as in the Illinois crude oil-petroleum sulfonate system are reported. The interdroplet coalescence behavior of oil-water emulsion systems appear to be quite different in enhanced oil recovery processes employing various alkaline agents as opposed to surfactant/polymer systems. 

Polymer-surfactant interactions are the basis for the rheological behavior of MHAPs. Other surfactant-polymer systems have previously been investigated. One example is the interaction of surfactants with polymers such as poly(ethylene oxide), which results in greater solution viscosities than with the polymer alone (e.g., ref. 25 and references therein). The interaction of surfactants or latexes with hydrophobically modified water-soluble polymers has also been shown to produce unique rheology (2, 5, 26, 27). In these systems, the latex particles or the surfactant micelles serve as reversible cross-link points with a hydrophobic region of a polymer molecule in dynamic association with a latex particle or surfactant micelle (27). 

With respect to the rheological parameters fliey come to the conclusion that surface elasticity effects are superior to surface viscosity effects. This, however, apphes to pure surfactant layers and may be different for pure protein or mixed surfactant/protein adsorption layers. It has been stressed also by Langevin (26), in her review on foams and emulsions, fliat studies on the dynamics of adsorption and dilational rheology studies for mixed systems, in particular surfactant-polymer systems, are desirable in order to understand these most common stabilizing systems. 

Part Two, Surfactants, contains chapters on the four major classes of surfactants, i.e. anionics, nonionics, cationics and zwitterionics, as well as chapters on polymeric surfactants, hydrotropes and novel surfactants. The physico-chemical properties of surfactants and properties of liquid crystalline phases are the topics of two comprehensive chapters. The industrially important areas of surfactant-polymer systems and environmental aspects of surfactants are treated in some detail. Finally, one chapter is devoted to computer simulations of surfactant systems. 

Surfactant-polymer systems have additional technological significance because surfactants are normally used in emulsion polymerization processes. 

---