Oil-soluble polymers

Chemicals of various types are used in every stage of drilling, completing, and producing oil and gas wells. This review describes these chemicals, why they are used, and recent developments. These chemicals include common inorganic salts, transition metal compounds, common organic chemicals and solvents, water-soluble and oil-soluble polymers, and surfactants. As existing fields become depleted, use of chemistry to maintain production via well stimulation, more efficient secondary recovery operations, and enhanced oil recovery become ever more important. 

Polymers with phenyl pendant groups such as those present in polystyrene undergo all of the characteristic reactions of benzene, such as alkylation, halogenation, nitration, and sulfonation. Thus, oil-soluble polymers (e.g., poly(vinyl cyclohexylbenzene) used as viscosity improvers in lubricating oils are obtained by the Friedel-Crafts reaction of polyst3frene... 

A novel alternative to the use of hydrogenated or saturated fats for structural stability in oil-continuous emulsions is the addition of oil-soluble polymers as thickening or texturizing agents (160). These polymers are condensation products of hydroxyacids or polyhydric alcohols and polybasic acids. Currently they are not approved for food use. Another option to hydrogenated oUs is to base the product on an oil-in-water emulsion. Such a product, which contains 80% liquid canola oil, has been introduced in the United States (140). 

Organocopper compounds inhibit oxidation of thin films of mineral oil (and ester) at 250°C [14, 21]. Under these conditions, polycondensation and polymerisation reactions are suppressed such that only medium-sized, oil-soluble polymers are formed. This leads to an improved control of viscosity [103]. A further stabilisation step, mainly in the upper part of the piston, may result from an interaction... 

The non-amphiphilic polymers can be widely considered as homopolymers or random copolymers. Most of the studies focussed on water-soluble polymers, but some studies on oil-soluble polymers exist as well. The water-soluble polymers can be uncharged or... 

Figure 4.9 Phase diagram of the system water-decane-CioE4 at equal volume fractions of water and decane as a function of the temperature T and the surfactant concentration cf>7. At low (f>7 there is a three-phase coexistence, while at moderate cf>7 the one-phase bicontinuous microemulsion appears. At even higher cf>7 the lamellar phase appears. At high and low temperatures a microemulsion phase coexists with either excess water or oil. The polymer fraction cf>p is raised symmetrically for the water- and oil-soluble polymers, and the one-phase microemulsion window closes continuously. The 2 K temperature shift is due to the use of heavy water. (From Ref. [40], reprinted with permission of the American Chemical Society.)...

Figure 20.28. On addition of a water-soluble non-associating polymer to a system of a bicontinuous microemulsion in equilibrium with excess water and oil, the distribution of the polymer will be very different for different molecular weights. A low-molecular-weight polymer is soluble in the microemulsion phase (a), whereas coils that are larger than the pore size of the microstructure are insoluble in the microemulsion phase and confined to the excess water phase (b) (or excess oil phase in the case of an oil-soluble polymer). (Redrawn from A. Kabalnov, B. Lindman, U. Olsson, L. Piculell, K. Thuresson and H. Wennerstrom, Colloid Polym. ScL, 274 (1996) 297)...

Polymers used in drag reduction are of two broad types Water soluble, and oil soluble. Some water soluble polymers include poly(ethylene oxide), PEO, polyacrylamide, PAM, partly hydrolyzed polyacrylamide, PAMH, and guar gum, GGM. Some oil soluble polymers include polyisobutylene, PIB, poly (methyl methacrylate), PMMA, and polydimethylsiloxane, PDMS. Table 14.10 (123) summarizes the molecular weight and concentration (in terms of weight parts per million, wppm) of the polymers illustrated in Figure 14.35 (123). 

The most spectacular success of polymer drag reducers has been the use of oil-soluble polymers in the trans-Alaska pipeline (122). Flow through the pipeline has been greatly increased by appropriate polymer addition. 

Water- and oil-soluble polymers are commercially available or can be synthesized by different routes. Among the most important requirements for technological applications of the water-soluble polymers, there are the high solubility in water, and easy and cheap route of synthesis, an adequate molecular weight and molecular weight distribution, chemical stability, high affinity for one or more metal ions, and selectivity for the metal ion of interest. The most usual synthetic procedures... 

The poly(alkylene oxide)s are linear or branched-chain polymers that contain ether linkages in their main polymer chain structure and are derived from monomers that are vicinal cyclic oxides, or epoxides, of aliphatic olefins, principally ethylene and propylene and, to a much lesser extent, butylene. These polyethers are commercially produced over a range of molecular weights from a few hundred to several million for use as functional materials and as intermediates. Lower polymers are liquids, increasing in viscosity with molecular weight. The high polymers can be thermoplastic. Solubilities range from hydrophilic water-soluble polymers that are principally derived from ethylene oxide, to hydrophobic, oil-soluble polymers of propylene oxide and butylene oxide. A wide variety of copolymers is produced, both random copolymers and block copolymers. The latter may be used for their surface-active characteristics. 

Microemulsions are thermodynamically stable oil-in-water emulsions, in which the droplet size (10-100 nm) is smaller than that in conventional emulsions (maaoemulsions 1-100 pm) and miniemulsions (50-500 nm). To prepare a stable miaoemul-sion, large amounts of anionic or cationic surfactants (more than 10-20% in the formulation or at similar levels as the monomer) and short-chain alcohols (e.g., n-pentanol) or other cosurfactants are employed. Upon polymerization of the microemulsion with a suitable initiator (either water soluble or oil soluble), polymer latexes with particle sizes in the 10-50 nm range and very high molar masses (>10 gmoT ) can be synthesized. 

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