Abstract: Propped fractures in formations from which fluids are produced are described that have wormholes extending out into the formations from the faces of the fractures at locations distant from boreholes. Methods are given for creating such propped fractures having wormholes in which either a closed propped fracture is formed and then the wormholes are formed, or the entire fracture and channel system is formed before the closure occurs.

Abstract: Propped fractures in formations from which fluids are produced are described that have wormholes extending out into the formations from the faces of the fractures at locations distant from boreholes. Methods are given for creating such propped fractures having wormholes in which either a closed propped fracture is formed and then the wormholes are formed, or the entire fracture and channel system is formed before the closure occurs.

Abstract: Propped fractures in formations from which fluids are produced are described that have wormholes extending out into the formations from the faces of the fractures at locations distant from boreholes. Methods are given for creating such propped fractures having wormholes in which either a closed propped fracture is formed and then the wormholes are formed, or the entire fracture and channel system is formed before the closure occurs.

Abstract: A low-temperature, low-rheology synthetic cement comprises an epoxy resin, catalyst and hardener and further including an aromatic solvent have the formula ##STR1## wherein R and R' are independently selected from hydrogen and C1 to C4 hydrocarbons.

Abstract: The invention comprises a selective plugging treatment with good penetration for acid diversion or water control. The fluid comprises a foamed delayed gelation system.

Abstract: The invention concerns delayed gelation systems which are injected under the shape of a foam in the chosen formations.The choise of an either oil compatible, or water compatible foaming agent allows obtaining a remarkable process selectivity.Plugging; acid diversion; water control treatments are carried out.

Abstract: A method is disclosed for recovering petroleum from a subterranean reservoir penetrated by at least one injection well and at least one production well comprising: injecting into the reservoir through the injection well a surfactant slug comprising an aqueous solution containing about 0.001 to about 5% by weight of an amphoteric surfactant and an effective amount of a high molecular weight homopolysaccharide gum thickener derived from fungus strains of the genus Schlerotium to provide the surfactant slug with a viscosity exceeding the viscosity of the petroleum in the reservoir; and recovering fluid from the production well.

Abstract: An improved method for enhanced oil recovery utilizing caustic or alkaline water flooding which avoids precipitation of hydroxides in the injection water or plugging of the reservoir. A lignosulfonate material is blended with the injection water before the addition of the alkaline chemical, the amount of lignosulfonate being sufficient to prevent formation of any precipitates.

Abstract: This invention relates to a process for separating heavy water from solutions. An anionic surfactant system is added to a solution of deuterium oxide in water. The separating agent added to the solution will form a first phase containing a majority of the surfactant with an increased concentration of D.sub.2 O and a second phase containing excess water with a decreased concentration of D.sub.2 O. The first stage is separated from the second stage, and the process is optionally repeated in a multi-stage or a continuous operation.

Abstract: Water-in-oil microemulsions useful as fire-resistant hydraulic fluids are prepared from an oil, such as mineral oil, water, emulsifiers, and an aliphatic diol, such as 2-ethyl-1,3-hexanediol.

Abstract: The optimal salinity of an emulsifier system comprising an alcohol and a neutralized oxidized solvent extracted oil can be controlled to match the salinity of the brine used in the tertiary oil recovery process by controlling the acid number of the solvent extracted oil during the oxidation procedure, controlling the extent of the neutralization during neutralization of the oxidized solvent extracted oil, or both.