Embodiments of the present disclosure are directed to double emulsified acids, specifically water in oil in water (W/O/W) double emulsions with an acidic interior water phase. The double emulsified acid may include two or more emulsifying agents. In addition to improving the stability of the emulsions, the emulsifying agents may help slow the acid reaction rate. The first emulsifying agent may have an HLB greater than 7 and the second emulsifying agent may have an HLB less than or equal to 7. Other embodiments are directed to methods for producing a double emulsified acid and methods for acidizing a carbonate formation including a double emulsified acid.

An emulsion for hydraulic fracturing to provide a one-step delivery of a fracturing fluid and a breaker for hydraulic fracturing of a hydrocarbon-bearing formation is provided. The emulsion for hydraulic fracturing is a water-in-oil-in-water emulsion having an internal aqueous phase that includes a breaker, an external aqueous phase that includes a fracturing fluid and a proppant, and an intermediate hydrocarbon phase separating the internal aqueous phase and external aqueous phase. The emulsion may include nanometer-sized or micrometer-sized particles to form a Pickering emulsion.

An emulsion for hydraulic fracturing to provide a one-step delivery of a fracturing fluid and a breaker for hydraulic fracturing of a hydrocarbon-bearing formation is provided. The emulsion for hydraulic fracturing is a water-in-oil-in-water emulsion having an internal aqueous phase that includes a breaker, an external aqueous phase that includes a fracturing fluid and a proppant, and an intermediate hydrocarbon phase separating the internal aqueous phase and external aqueous phase. The emulsion may include nanometer-sized or micrometer-sized particles to form a Pickering emulsion.

A system and methods for breaking friction reducers in subterranean formations in-situ during hydraulic fracturing operations are disclosed. A method of fracturing a subterranean formation is disclosed, including providing a well treating fluid, adding a friction reducer into a water phase of an emulsion, adding a breaker into the water phase, and injecting the well treating fluid into the subterranean formation at a pressure sufficient to fracture the subterranean formation and invert the emulsion and double emulsion, thereby allowing the breaker to break the friction reducer. A friction reducer-breaker system for breaking a friction reducer polymer in-situ is also disclosed, including an oil phase, a water phase including friction reducer polymers and breakers in double emulsion dispersed throughout the water phase, wherein the emulsion and double emulsion are configured to invert under shear, thereby providing for mixing between the friction reducer polymers and the breakers.

Embodiments of the present disclosure are directed to double emulsified acids, specifically water in oil in water (W/O/W) double emulsions with an acidic interior water phase. The double emulsified acid may include two or more emulsifying agents. In addition to improving the stability of the emulsions, the emulsifying agents may help slow the acid reaction rate. The first emulsifying agent may have an HLB greater than 7 and the second emulsifying agent may have an HLB less than or equal to 7. Other embodiments are directed to methods for producing a double emulsified acid and methods for acidizing a carbonate formation including a double emulsified acid.

The invention relates to an emulsion containing or consisting of (A) 40.00 to 97.98 wt. % of at least one hydrocarbon, (B) 2.00 to 59.98 wt. % of water or an aqueous solution of a salt which does not fall under the following definition according to (C) and (C) 0.02 to 8.00 wt. % of a salt of an amino amide of a fatty acid, containing at least one primary, secondary or tertiary amino group, and an acid component of general formula (I)

##STR00001## in which R.sup.1 is a linear or branched, saturated or mono-unsaturated or poly-unsaturated hydrocarbon radical with 1 to 40 C atoms, R.sup.2 is an alkylene radical or arylalkylene radical with 2 to 20 C atoms and X is a radical which contains at least one acid group, m=0 or 1, n=1 to 30, wherein the weight proportions of components (A), (B) and (C) relate to the sum of the masses of these components and this is 100 wt. %. The invention also relates to a method for the production of the emulsion, to an oil-based drilling mud and to a method for creating and stabilizing a drill hole.

The present disclosure generally relates to a system and methods for breaking friction reducers in subterranean formations in-situ during hydraulic fracturing operations. A method of fracturing a subterranean formation is disclosed, including providing a well treating fluid, adding a friction reducer into a water phase of an emulsion, adding a breaker into the water phase, and injecting the well treating fluid into the subterranean formation at a pressure sufficient to fracture the subterranean formation and invert the emulsion and double emulsion, thereby allowing the breaker to break the friction reducer. A friction reducer-breaker system for breaking a friction reducer polymer in-situ is also disclosed, including an oil phase, a water phase including friction reducer polymers and breakers in double emulsion dispersed throughout the water phase, wherein, the emulsion and double emulsion are configured to invert under shear, thereby providing for mixing between the friction reducer polymers and the breakers.

An emulsion for hydraulic fracturing to provide a one-step delivery of a fracturing fluid and a breaker for hydraulic fracturing of a hydrocarbon-bearing formation is provided. The emulsion for hydraulic fracturing is a water-in-oil-in-water emulsion having an internal aqueous phase that includes a breaker, an external aqueous phase that includes a fracturing fluid and a proppant, and an intermediate hydrocarbon phase separating the internal aqueous phase and external aqueous phase. The emulsion may include nanometer-sized or micrometer-sized particles to form a Pickering emulsion.

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.