Abstract: This invention relates to a composition of matter and to a method for producing a controllable, residue-free break of an emulsion or a dispersion of a water-in-oil emulsion. An emulsion breaker is incorporated into the emulsion. It is temporarily-protected (deactivated) so that breaking of the emulsion is initially avoided. By removing the protection, the breaker becomes active, and it acts to break the emulsion into its separate phases.

Abstract: In a method of treating a subterranean formation, a well treatment composition comprising a dispersion of a water-in-oil emulsion in an aqueous medium is injected into the formation. The water-in-oil emulsion has an internal aqueous phase and an external phase containing a liquid hydrocarbon and a surfactant soluble in the hydrocarbon. The compositions can be designed to perform various well treatment applications including hydraulic fracturing and acidizing and can also be used to encapsulate or to transport well treatment materials and chemicals into the wellbore or formation. Treatment methods may also employ dispersions of a reactive simple or multiple emulsion. The distinct phases of the compositions may be selected to form treatment solutions upon mixing. Thus, improved acidizing may be achieved through an in situ reaction format.

Abstract: A method of treating a subterranean formation wherein a well treatment composition comprising a dispersion of a water-in-oil emulsion in an aqueous medium is injected into the formation. The water-in-oil emulsion has an internal aqueous phase and an external phase containing a liquid hydrocarbon and a surfactant soluble in the hydrocarbon. The compositions can be designed to perform various well treatment applications including hydraulic fracturing and acidizing and can also be used to encapsulate or transport well treatment materials and chemicals into the wellbore or formation.

Abstract: A method and apparatus for sampling the composition of fluid flowing through a conduit which includes a sampling conduit having an inlet disposed within said conduit and transverse to the axis of fluid flow in said conduit and an outlet connected to said conduit downstream of said inlet, and means for measuring the composition of fluid flowing through the sampling conduit. The sampling conduit is sized in relation to the conduit to cause isokinetic withdrawal of fluid from said conduit into said sampling conduit.

Abstract: A method of preventing the failure of a sand consolidation treatment due to contamination of the resinous material with aqueous rathole fluids during injection is described. The method involves displacing the aqueous rathole fluids with a dense, nonaqueous liquid prior to introducing the resinous material into the formation.

Abstract: A method is disclosed for generating or forming hydrofluoric acid in a subterranean siliceous formation by combining an injected aqueous solution of a fluoride salt and an injected aqueous acid solution in the pore spaces of the formation. This is accomplished according to this invention by immobilizing one of the aqueous solutions in the pore spaces of the formation by displacing the aqueous solution into the formation with a liquid that is substantially immiscible with the injected aqueous solution, thereby driving said aqueous solution to a saturation at or below its residual saturation. The other aqueous solution is then injected into the formation.

Abstract: The annular passage defined by the interior of a perforated liner and the exterior of a stinger pipe extending through the liner is substantially restricted so that the resistance to flow in the annular passage is increased sufficiently to maintain high fluid flow velocity outside the liner during gravel packing. The increased flow velocity prevents the premature settling of gravel and stabilizes the formation of gravel dunes in the wellbore annulus, thereby significantly increasing gravel packing efficiency in inclined wells. The proper flow restriction can be obtained using a wide diameter stinger pipe.

Abstract: A method of controlling the migration of fines in a subterranean formation comprising contacting the formation with a dilute resin solution; displacing the resin solution into the formation, preferably with an overflush oil, so as to leave behind a thin film of resin solution; extracting the diluent present in the resin, and then curing the resin to an infusible state. The preferred resin is a one-step phenolic type resin which cures at formation temperatures and which should comprise from about 5 to about 30 weight percent of the resin solution and preferably about 10 to 20 weight percent.

Abstract: A perforated liner is sealed at longitudinally spaced intervals with a removable sealant. The partially sealed liner maintains sufficiently high fluid flow velocity outside the liner during gravel packing so as to prevent the formation of gravel dunes. After packing is completed, the sealant is removed permitting the passage of fluids through the liner.

Abstract: A hydraulic fracturing method wherein a viscous oil-in-water emulsion is injected into a formation under sufficient pressure to fracture the formation. The emulsion contains from about 70 to about 90 volume percent of an internal liquid hydrocarbon phase, from about 10 to about 30 volume percent of an external aqueous phase and sufficient amounts of a nonionic surfactant to stabilize and viscosify the emulsion. The preferred hydrocarbon phase concentration is between about 75 and 85 volume percent. The nonionic surfactant also gives the emulsion a breaking temperature which is not greater than the temperature of the formation. Preferably, an electrolyte is used to adjust the temperature at which the emulsion will break. After fracturing is completed the emulsion is then left in the wellbore for a sufficient time to permit the temperature of the emulsion to reach its breaking temperature. Upon breaking, the emulsion reverts to a low viscosity fluid which is readily removable from the formation.

Abstract: A method of consolidating incompetent subterranean formation surrounding a well wherein a liquid resin diluted with a two-part diluent is injected into the formation and is followed by an overflush liquid to extract the diluent but leave the resin on the sand grains. The two-part diluent comprises a first component miscible with the resin and a second component immiscible with the resin but miscible with the first component and the overflush liquid.