Abstract: A method of removing hydrocarbon-based adherent, for example bitumen, from a solid substrate, for example tar sands comprises contacting the solid substrate which includes associated hydrocarbon-based adherent with a treatment formulation which includes a polymeric material which includes vinylalcohol and vinylacetate repeat units. The polymeric material may be a 70-95 mole % hydrolysed polyvinylalcohol.

Abstract: A method of fracturing a subterranean formation using a formulation comprising oil, polyvinylalcohol, water and, optionally, a proppant. The method involves introducing the formulation into the formation at a pressure sufficient to fracture the formation.

Abstract: There is disclosed a method of separating a mixture (e.g. dispersion) of oil and water into oil-rich and water-rich phases, the method comprising the steps: (i) selecting a mixture which comprises oil recovered from a subterranean formation and a treatment formulation, wherein said treatment formulation was added to the oil in order to facilitate its recovery and/or mobility, wherein said treatment formulation has an Interfacial Tension (IFT), measured against a sample of said oil in the range 2 to 20 mN/m; (ii) directing said mixture to a separation means; and (iii) in the absence of a chemical demulsifier, heating the mixture until separation is effected at least partially under gravity. Preferably the IFT is in the range 9 to 12 mN/m. The mixture of oil and water may be formed by treating oil in a subterranean formation.

Abstract: A treatment formulation for use in enhanced oil recovery is described which includes a dispersing polymer which may be a partly hydrolyzed polyvinyl alcohol and a displacing polymer which may be a partially hydrolysed polyacrylamide.