Hydrophobically associating polymers

X HE RHEOLOGICAL PROPERTIES OF WATER-BASED FLUIDS can be controlled with hydrophobically associating polymers. Hydrophobically associating polymers are synthetically derived, water-soluble polymers that contain a small number of oil-soluble or hydrophobic groups. When these polymers are dissolved in aqueous solution, the hydrophobic groups aggregate to minimize their exposure to water, in a fashion analogous to that of surfactants... 

HEUR hydrophobically associating polymer (hydrophobically modified, ethoxy-lated urethane resin)... 

J. Bock and co-workers, "Hydrophobically Associating Polymers," ia G. A. Stahl and D. N. Schul2, eds., Water-Soluble Polymers for Petroleum Recorey, Plenum Press, New York, 1988, pp. 147—160. 

Some works were reported in which thermosensitive polymers were conjugated with hydrophobic groups. End-capping random poly(NIPA-co-dimethylacrylamide) [55] and grafting poly(NIPA-co-hydroxymethylacryl-amide) [56] with cholesterol moieties led to self-associating polymers with different morphologies. By dissolution of the copolymers in dimethylfor-... 

The conversion of dextran with 1,2-epoxy-3-phenoxypropane, epoxyoctane or epoxydodecane may be exploited for the preparation of amphiphilic dextran derivatives. Polymeric surfactants prepared by hydrophobic modification of polysaccharides have been widely studied, starting with the pioneering work of Landoll [261]. Neutral water-soluble polymeric surfactants can be obtained by reaction of dextran with 1,2-epoxy-3-phenoxypropane in 1 M aqueous NaOH at ambient temperature (Fig. 35, [229,233]). The number n of hydrophobic groups per 100 Glcp units varies between 7 and 22 depending on the reaction conditions. 2-Hydroxy-3-phenoxy propyl dextran ethers (DexP) behave like classical associative polymers in aqueous solution. In dilute solution, the intrinsic viscosity decreases significantly whereas... 

In conclusion, lowering surface tension, which translates Into some surface accumulation, while necessary for foaming. Is only part of the process. A companion effect Is the formation of viscous surface and subsurface layers which can stabilize the lamellae. The new polymer would seem Ideal for the latter effect. A depiction of the situation prevailing Is attempted In Figure 6 which shows Inter-and Intramolecular bonds between hydrophobic groups In the polymer chains. Polymers which exhibit these types of Interaction are referred to as associating polymers. It should be noted that considerable levels of surface vlsco-elastlclty were also detected In adsorbed films of the polymer. 

Copolymerization of the CD-complexed macromonomer 8a with hydrophilic comonomers 2-acrylamido-2-methylpropansulfonate (AMPS) and A,A-dimethyl-acrylamide (DMAA) leads to formation of hydrophobically associative polymers (Fig. 14) [48],... 

The polymer is hydrophobically associating water soluble, meaning it contains one or more water-soluble monomers (acrylamides) and a small fraction (0.5 to 4%) of water-insoluble (hydrophobic) monomers. A typical hydrophobically associating polymer (HAP) structure is... 

This shear reversibihty is very beneficial in enhanced oil recovery field applications. It improves the well injectivity because of the shear thinning effect at the perforation and near the wellbore. Far away from the wellbore, flow velocity is reduced and viscosity is restored. For the hydrophobically associating polymers, both shear thickening and shear thinning were observed by Bock et al. (1988). It has also been reported that the viscosity after shearing was stopped was higher than that before shearing (McCormick et al., 1988). 

Core flood results show that the oil recovery factor using hydrophobically associating polymers was a few percent higher than that using the HPAM type of polymers (Wang et al., 1999c On-Yang et al., 2004 Luo et al., 2006). The... 

Chen, H., Zhang, S.H., Chu, Y.B., Yang, H.X., Liu, F.L., 2004. Development and application of hydrophobically associating polymer gel in high-temperature and high-salinity reservoirs for profile modification. Oilfield Chemistry 21 (4), 343-346. 

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