Abstract: 1,1-dichloro-2,2,2-trifluoroethane or 1,1-dichloro-1-fluoroethane are employed as solvents to remove oleophylic material from mineral particulates. In one aspect the method of this invention includes the steps of transporting oil-based mud-laden cuttings to a solid feed tank wherein the oil-based cuttings are subjected to turbulent mixing to leave the surface of the cuttings substantially free of oil. The cuttings are then subjected to countercurrent flow of solvent in order to separate oily solvent and fines smaller than a chosen diameter from the heavier solids. The heavier solids are cleaned of any remaining oil-based muds, separated from cleaning solvent and ultimately returned to the sea environment.

Abstract: An improved sulfonate suitable for waterflooding is formed by sulfonating a blend of two alkyl aromatic feedstocks, one being a high molecular weight monoalkylbenzene while the second is a mixture of normal alkyl aromatic compounds such as monoalkyl benzenes, dialkylbenzenes, and diphenyl alkanes. This feedstock is either sulfonated after blending or before blending to provide a blended non-sulfonate/sulfonate ratio in the range of 0.10 to 0.25. The sulfonate effectiveness of this system increases as the non-sulfonate/sulfonate ratio increases.

Abstract: Filterability of aqueous solutions of polymers employed to thicken waterfloods such as biopolymers (e.g. heteropolysaccharides) is improved by addition of a surfactant (e.g. a sulfated alkoxylated alcohol). Filterability is further enhanced by addition of an ethoxylated alcohol surfactant and/or an alcohol.

Abstract: In an enhanced recovery process involving flooding of subterranean formations with aqueous mixtures of biopolymers, filterability of the biopolymer is synergistically enhanced by treatment with ESPERASE.RTM. enzyme at a pH range of 12.5 to 13.0. The range is narrow and exclusive since pHs as high as 12.1 give poor results. The biopolymer can be any one containing debris which must be reduced by the enzyme.