Abstract: A method for enhancing the stability of a solids-stabilized water-in-oil emulsion by pretreating the oil prior to emulsification. The pretreatment step can be accomplished by adding dilute acid to the oil, adding a lignosulfonate additive to the oil, sulfonating the oil, thermally oxidizing the oil, thermally treating the oil in an inert environment, and combinations thereof. The emulsion can be used in enhanced oil recovery methods, including using the emulsion as a drive fluid to displace hydrocarbons in a subterranean formation, and using the emulsion as a barrier fluid for diverting flow of fluids in the formation.

Abstract: A method for enhancing the stability of a solids-stabilized water-in-oil emulsion by pretreating the oil prior to emulsification. The pretreatment step can be accomplished by adding dilute acid to the oil, adding a lignosulfonate additive to the oil, sulfonating the oil, thermally oxidizing the oil, thermally treating the oil in an inert environment, and combinations thereof. The emulsion can be used in enhanced oil recovery methods, including using the emulsion as a drive fluid to displace hydrocarbons in a subterranean formation, and using the emulsion as a barrier fluid for diverting flow of fluids in the formation.

Abstract: Novel water soluble terpolymers of acrylamide, an alkali metal or ammonium salt of acrylic acid and an oil soluble or hydrophobic alkyl acrylamide monomer have been found to provide efficient viscosification of water or brine solutions. The polymers are prepared by a free radical micellar polymerization of acrylamide and alkyl acrylamide followed by base catalyzed partial hydrolysis. These terpolymers, called HRAM, impart unique and useful rheological properties to aqueous solutions. In a water or brine solution the hydrophobic groups associate to increase hydrodynamic size and enhance thickening efficiency. Solutions containing the HRAM terpolymers show increased viscosification at higher polymer concentration and reduced salt sensitivity relative to polyacrylamide based HPAM solutions.

Abstract: Novel water soluble copolymers of acrylamide, oil soluble higher alkylacrylamide and alkali metal acrylate have been found to provide efficient viscosification of water or brine. The process for synthesizing them relies on the complete solubilization of the water insoluble monomer into an aqueous solution of the water soluble monomer(s) by means of a suitable water soluble surfactant. A redox initiator system is used in conjunction with high monomer concentration and a low reaction temperature. The surfactant chosen and its concentration is one that produces a clear, uniform, homogeneous mixture in the presence of the monomers and gives a product which remains a clear uniform, homogeneous mixture with no phase separation as the reaction proceeds toward completion. The molecular weight of the resulting polymer after isolation from the surfactant is sufficiently high that it gives an intrinsic viscosity greater than about 12 dl/g.

Abstract: The dispersed aqueous phase of a shear thickening composition, useful as a well control fluid which comprises a water-in-oil emulsion having hydratable, water-expandable hydrophillic clay, dispersed in the continuous, surfactant-containing oily phase thereof, hydratable, water-expandable hydrophillic clay, is prepared by mixing an aqueous solution of a polyacrylamide with an aqueous solution of polyacrylic acid wherein the concentration of the polymer in each separate solution used to prepare said aqueous phase is less than about 2 wt %.

Abstract: Novel water soluble copolymers of acrylamide, oil soluble higher alkylacrylamide and alkali metal acrylate have been found to provide efficient viscosification of water or brine. The process for synthesizing them relies on the complete solubilization of the water insoluble monomer into an aqueous solution of the water soluble monomer(s) by means of a suitable water soluble surfactant. A redox initiator system is used in conjunction with high monomer concentration and a low reaction temperature. The surfactant chosen and its concentration is one that produces a clear, uniform, homogeneous mixture in the presence of the monomers and gives a product which remains a clear uniform, homogeneous mixture with no phase separation as the reaction proceeds toward completion. The molecular weight of the resulting polymer after isolation from the surfactant is sufficiently high that it gives an intrinsic viscosity greater than about 12 dl/g.

Abstract: Surfactant-free stable aqueous foams may be produced by water soluble copolymers of acrylamide and N-alkylacrylamide with chain lengths greater than or equal to 6 carbons. Additionally, these polymers may contain an anionic monomer, such as a monovalent salt of acrylic acid. These copolymers and terpolymers are added to water or brine at a concentration of 0.005 to 2 parts per 100 of solvent. When the resulting solutions are subjected to intensive mixing with the addition of air or other gases, such as nitrogen or carbon dioxide, high quality, persistent foams are formed. These foams are formed at relatively low polymer concentrations without added surfactants. They have good high temperature stability and excellent salt tolerance.

Abstract: The copolymerization of water soluble monomers with water insoluble monomers can be effected by using a solution of a water soluble surfactant to solubilize the water insoluble monomer. The aqueous medium containing the surfactant and water insoluble monomer is therefore a homogeneous, isotropic, transparent dispersion, into which the water soluble monomer can be dissolved and, after addition of a suitable free radical initiator, can be copolymerized to give a reaction mixture which does not phase separate, or contain substantial amounts of particulates of insoluble monomer. The copolymers which may be isolated from the reaction mixture are good viscosifiers of water and brine.

Abstract: The copolymerization of water soluble monomers with water insoluble monomers can be effected by dissolving the water insoluble monomer into a homogeneous mixture of oil, surfactant, and cosurfactant and then diluting this with water containing the water soluble monomer to yield a predominently aqueous, homogeneous, transparent dispersion of microemulsion droplets. The polymerization is initiated with water soluble free radical initiators to give copolymers that are free of visible particulates and such that the reaction product remains homogenous. The components are chosen to yield copolymers that are water soluble and which viscosify at low concentrations.

Abstract: Water soluble acrylamide/alkylacrylamide copolymers which are efficient viscosifiers of water or brine are described. They are made by processes which finely disperse the water insoluble alkylacrylamide into a water-external microemulsion or a micellar surfactant solution.

Abstract: A method for reducing frictional drag of water in flow through pipes comprising adding about 5 to about 100 ppm of a water soluble copolymer to said water, said copolymer having the formula: ##STR1## wherein R.sub.1 is an alkyl or cycloalkyl group having about 6 to about 22 carbon atoms, R.sub.2 is the same or different alkyl group as R.sub.1 or hydrogen, x is about 90.0 to about 99.9 mole %, and y is about 0.1 to about 10.0 mole %.