Abstract: The present invention relates to a method of stabilizing argillaceous rocks containing reactive clays in the presence of water, wherein said argillaceous rocks are placed in contact with an aqueous solution containing a polymer with hydrophilic groups and hydrophobic groups.

Abstract: Enhanced gel properties (e.g., faster gel time, higher attainable gel strengths) are achieved by reducing the pH and/or increasing the salt of a monovalent and/or divalent cation concentration of an aqueous reaction medium in which a polymer is reacted with an organic crosslinking agent. In addition, the gelation time of an aqueous composition comprising a polymer and an organic crosslinking agent is reduced by heating the composition above about 48.9.degree. C. (120.degree. F.) prior to injecting the composition into a subterranean formation. Alternatively, the gelation time of the aqueous composition is increased by incorporating a pH increasing agent into the composition.

Abstract: Visible gels are formed by mixing an inorganic crosslinking agent with a low viscosity aqueous solution having a low polyacrylamide concentration and devoid of polymers containing a vicinal diol pendant group. The visible gels are employed to reduce the water/hydrocarbon permeability ratio of subterranean formations.

Abstract: A gelable composition and process are disclosed that delay the gelation and increase the gel strength of gelled water soluble acrylamide-containing polymers contains: (1) a water dispersible first crosslinking compound selected from the group consisting of p-aminosalicylic acid, furfuryl alcohol, RArOC(O)R' and HOArC(O)OR" wherein Ar represents a phenyl group which can be substituted or non-substituted; R is a hydrogen or a carboxylic group; R' is a C.sub.1 -C.sub.6 alkyl; R" is a hydrogen, a phenyl group, or a C.sub.1 -C.sub.6 alkyl; and when R is a carboxylic group, R and C(O)OR" can be at ortho, meta, or para position with respect to the OC(O)R' group and the OH group, respectively; (2) a water dispersible second crosslinking compound selected from the group consisting of aldehydes and aldehyde-generating compounds; (3) a water soluble acrylamide-containing polymer; and (4) water.