Provided is an injection fluid that may include a nanoemulsion having an oil phase dispersed in an aqueous phase, and non-superparamagnetic magnetic nanoparticles that are present in the dispersed oil phase. Further provided is a method for preparing an injection fluid that may include preparing a nanoemulsion from an aqueous phase and an oil phase having non-superparamagnetic magnetic nanoparticles therein, and may be used to form nanodroplets of the non-superparamagnetic magnetic nanoparticles. Further provided is a method for tracking movement of an injection fluid. The method may include introducing a tagged injection fluid into a hydrocarbon-containing reservoir, the tagged injection fluid may be a nanoemulsion that includes: an aqueous phase, an oil phase dispersed in the aqueous phase, and non-superparamagnetic nanoparticles that are present in the dispersed oil phase; and tracking the movement of the tagged injection fluid.

The instant invention relates to a process for the encapsulation of a non-amine hydrophilic compound C, comprising the steps of: (E1) providing a reverse emulsion containing: an oil phase (O), comprising a curable mixture of isocyanate and polyalkyldiene hydroxylated or polyol dispersed in said oil phase, drops of an aqueous phase W.sup.1, containing: said non-amine hydrophilic compound C; and at least 5% by weight of a compound C carrying more than 2 amine groups; (E2) pouring the reverse emulsion of step (E1) in a second water phase W.sup.2 to make a multiple emulsion water/oil/water; and, then, (E3) curing into polyurethane all or part of the curable mixture contained in the oil phase.

Provided is an injection fluid that may include a nanoemulsion having an oil phase dispersed in an aqueous phase, and non-superparamagnetic magnetic nanoparticles that are present in the dispersed oil phase. Further provided is a method for preparing an injection fluid that may include preparing a nanoemulsion from an aqueous phase and an oil phase having non-superparamagnetic magnetic nanoparticles therein, and may be used to form nanodroplets of the non-superparamagnetic magnetic nanoparticles. Further provided is a method for tracking movement of an injection fluid. The method may include introducing a tagged injection fluid into a hydrocarbon-containing reservoir, the tagged injection fluid may be a nanoemulsion that includes: an aqueous phase, an oil phase dispersed in the aqueous phase, and non-superparamagnetic nanoparticles that are present in the dispersed oil phase; and tracking the movement of the tagged injection fluid.

Method for increasing lubricity of a wellbore fluid comprising the following steps: i) preparing a water in oil microemulsion that contains insoluble particles of metal hydroxides and/or metal oxides in the inner aqueous phase, the insoluble particles being synthesized from their salt precursors in the water droplets of the microemulsion; ii) adding to the wellbore fluid the water in oil microemulsion; iii) injecting the wellbore fluid into a subterranean formation and iv) performing the drilling, completion or coiled tubing operations in the subterranean formation.

A fiber silica composite microsphere for a shale stratum comprises a hollow silica sphere and fibers, and the fibers are partially coated on an outer surface of the hollow silica sphere and partially embedded into an interior of the hollow silica sphere. The hollow silica sphere has an outer diameter of 1-5 μm and an inner diameter of 0.8-4.7 μm; the fibers have a length of 5-10 μm and a width of 1-3 μm.

A water-in-oil emulsion that includes an oil phase (O) and an aqueous phase (A) at an O/A ratio of from about 1:8 to about 10:1; wherein the water-in-oil emulsion includes the oil phase as a continuous phase that includes an inert hydrophobic liquid, at least one water-insoluble hydrophobic monomer, and at least one surfactant, and the aqueous phase as a dispersed phase of distinct particles in the oil phase that includes water and a water soluble polymer that includes: (i) at least one acrylamide monomer and (ii) at least one acrylic acid monomer; wherein the water soluble polymer is present in an amount from about 10 to about 35 weight percent of the water-in-oil emulsion. Also provided is water-in-oil emulsion that includes an oil phase (O) and an aqueous phase (A) at an O/A ratio of from about 1:8 to about 10:1; wherein the water-in-oil emulsion includes the oil phase as a continuous phase that includes an inert hydrophobic liquid and at least one surfactant, and the aqueous phase as a dispersed phase of distinct particles in the oil phase that includes water and a water soluble polymer that includes: (i) at least one acrylamide monomer, (ii) at least one acrylic acid monomer, and (iii) at least one water soluble hydrophobic monomer; wherein the water soluble polymer is present in an amount from 10 to 35 weight percent of the water-in-oil emulsion. Methods of treating a portion of a subterranean formation with a water-in-oil emulsion are also provided.

The present invention relates to an aqueous multiphase particulate suspension comprising a water-soluble polymer and to an enhanced oil recovery method using said suspension. The invention further relates to the use of the multiphase suspension in a drilling, hydraulic fracturing and mining effluent treatment operation.

A method for hydraulic fracturing of a subterranean formation includes injecting an oil-based fracturing fluid into the subterranean formation through a well. The method also includes injecting a second fracturing fluid, for example a water-based fracturing fluid, into the subterranean formation through the well after completion of the injection of the oil-based fracturing fluid.

A polymer-encapsulated mineral acid solution and a method for forming the polymer-encapsulated mineral acid solution. Introducing a strong mineral acid solution to a monomer solution occurs such that a primary emulsion that is a water-in-oil type emulsion forms. Introducing the primary emulsion to a second aqueous solution forms a secondary emulsion that is a water-in-oil-in-water type double emulsion. The monomer in the secondary emulsion is cured such a polymerized shell forms that encapsulates the strong mineral acid solution and forms the capsule. The strong mineral acid solution has up to 30 wt. % strong mineral acid. A method of stimulating a hydrocarbon-bearing formation using the polymer-encapsulated mineral acid solution includes introducing a capsule suspension into a fissure in the hydrocarbon-bearing formation to be stimulated through a face in a well bore. The capsule is maintained within the fissure until the polymer shell degrades.

A polymer-encapsulated mineral acid solution and a method for forming the polymer-encapsulated mineral acid solution. Introducing a strong mineral acid solution to a monomer solution occurs such that a primary emulsion that is a water-in-oil type emulsion forms. Introducing the primary emulsion to a second aqueous solution forms a secondary emulsion that is a water-in-oil-in-water type double emulsion. The monomer in the secondary emulsion is cured such a polymerized shell forms that encapsulates the strong mineral acid solution and forms the capsule. The strong mineral acid solution has up to 30 wt. % strong mineral acid. A method of stimulating a hydrocarbon-bearing formation using the polymer-encapsulated mineral acid solution includes introducing a capsule suspension into a fissure in the hydrocarbon-bearing formation to be stimulated through a face in a well bore. The capsule is maintained within the fissure until the polymer shell degrades.