A breaker composition for use in a fracturing fluid comprises at least one organic peroxide (e.g., tert-butyl hydroperoxide), at least one dye (e.g., an FD&C dye), and at least one alcohol (e.g., propylene glycol). A promoter composition for use in a fracturing fluid comprises at least one promoter (e.g., sodium thiosulfate), at least one dye (e.g., an FD&C dye). According to certain embodiments, the dye increases the efficiency of the promoter and/or the organic peroxide, so that the break time and the peak viscosity of the aqueous treatment fluid are reduced.

A viscosified aqueous solution, optionally for use in a subterranean wellbore, is made by reacting in aqueous solution (i) an initial polymer with either carboxylic acid or amino groups on its polymer chain, (ii) a second compound with an amino group or carboxylic acid group, and (iii) a coupling agent, so that molecules of the second compound join to the polymer chain through amide groups, thereby forming an aqueous solution of a modified polymer which, without separation from the aqueous solution, participates in cross-linking thereby enhancing viscosity of the solution. The second compound may include hydrophobic groups so that the modified polymer contains hydrophobic groups and is able to cross-link with itself or a viscoelastic surfactant through association of hydrophobic groups (without covalent bond formation) in aqueous solution. Such cross-links can reform after the fluid has been subjected to shear.

Shale inhibiting additives for subterranean drilling and/or treatment fluids that include polyvinyl alcohol (PVA) are provided. In some embodiments, the methods include: providing a treatment fluid including an aqueous base fluid and a shale inhibiting additive including polyvinyl alcohol; introducing the treatment fluid into at least a portion of a subterranean formation to contact at least a portion of the subterranean formation that comprises shale; and allowing the shale inhibiting additive to interact with the shale in the subterranean formation to at least partially inhibit the shale.

The present invention relates to multi-arm star macromolecules which are used as thickening agents or rheology modifiers, including use in hydraulic fracturing fluid compositions. In one aspect of the invention, a star macromolecule is capable of thickening via a dual mechanism comprising (1) self-assembly of the hydrophobic polymerized segments of the star macromolecules via hydrophobic interactions or associations, and (2) association, reaction, or combination of the hydroxyl-containing polymerized segments of one or more of the star macromolecules.

Proppant-free channels may be formed in a proppant pack in subterranean formations by using the miscibility and immiscibility of proppant-laden and proppant-free fluids. For example, a method of forming a proppant pack may include: introducing, in alternating order, a proppant-laden fluid and a proppant-free fluid into a wellbore penetrating a subterranean formation, wherein the proppant-laden fluid comprises an oil-external emulsion and a proppant, and wherein the proppant-free fluid is immiscible with the proppant-laden fluid; and forming a proppant pack in a fracture in the subterranean formation, wherein the proppant pack comprises proppant-laden clusters and proppant-free channels.

A composition and method for treating a subterranean formation that includes preparing a treatment gel of aqueous fluid, a thickening agent and nanoparticles. Placing the treatment gel in at least a portion of the subterranean formation and placing a gel breaker in at least a portion of the subterranean formation to break the treatment gel to a residual treatment fluid having decreased viscosity.

A crosslinked polymer comprising reactants of a first repeating unit, a second repeating unit, and a crosslinker that react to form the crosslinked polymer, wherein the first repeating unit is a sulfonic acid-containing monomer present from 1% to 45% by weight of the reactants, wherein the second repeating unit is selected from the group consisting of an N-vinyl amide-containing monomer, a terminal double bond-containing monomer, and any combination thereof, and is present from 55% to 99% by weight of the reactants, and wherein the crosslinker comprises at least two olefinic bonds.

A composition for use as a pressure-tolerant dual-crosslinker gel in a fracturing fluid that comprises polymer, the polymer operable to increase the viscosity of a fluid; boron-containing crosslinker, the boron-containing crosslinker operable to crosslink the polymer; and a transition metal oxide additive, the transition metal oxide additive operable to crosslink the polymer.

A fracturing fluid system for increasing hydrocarbon production in a subterranean reservoir formation comprising a fluid composition and a base fluid, the fluid composition comprising a nano-crosslinker, and a base polymer; and the base fluid operable to suspend the fluid composition, the base fluid comprising water; wherein the fluid composition and the base fluid are combined to produce the fracturing fluid system, wherein the fracturing fluid system is operable to stimulate the subterranean reservoir formation. In certain embodiments, the nano-crosslinker is an amine-containing nano-crosslinker and the base polymer is an acrylamide-based polymer. In certain embodiments, the fracturing fluid systems comprise proppants for enhancing hydraulic fracturing stimulation in a subterranean hydrocarbon reservoir.

A crosslinked polymer comprising reactants of a first repeating unit, a second repeating unit, and a crosslinker that react to form the crosslinked polymer, wherein the first repeating unit is a sulfonic acid-containing monomer present from 50% to 99% by weight of the reactants, wherein the second repeating unit is selected from the group consisting of an N-vinyl amide-containing monomer, a terminal double bond-containing monomer, and any combination thereof, and is present from 1% to 50% by weight of the reactants, and wherein the crosslinker comprises at least two olefinic bonds, and is present in the range of about 9% to about 25% by weight of the reactants.