Methods including preparing a treatment fluid comprising an aqueous base fluid, a gelling agent, and crosslinker-coated particulates, wherein the crosslinker-coated particulates are formed by at least partially coating a particulate with a stabilizing agent, and at least partially coating the particulate with a first crosslinking agent atop the stabilizing agent, wherein the stabilizing agent imparts a hydrophobic nature to the particulate when the stabilizing agent is at least partially coated onto the particulate; introducing the treatment fluid into a subterranean formation, and reacting the first crosslinking agent with the gelling agent in the treatment fluid so as to crosslink the gelling agent and suspend the crosslinker-coated particulates.

The present disclosure relates to a crosslinking composition for use in crosslinking an aqueous suspension of guar, for use as a well treatment fluid and/or proppant carrier fluid for natural gas extraction. The present crosslinking composition is an aqueous suspension of hydroboracite. The composition may also comprise varying amounts of borax, canola oil, xanthan, glycerol, and/or NaOH. The composition may be selected to effect a desired delay in the crosslinking reaction in order to customize the viscosity and reaction time to the method of use, thereby maximizing proppant delivery while minimizing pump pressure.

A well treatment fluid is disclosed containing water, a crosslinkable component, a crosslinker; and an enzyme breaker containing a cellulase enzyme, the well treatment fluid having a total dissolved solids content of at least about 75,000 mg/L up to about 250,000 mg/L. A method of treating a subterranean formation is also disclosed including placing the well treatment fluid in the subterranean formation. It is also disclosed that the well treatment fluid can be a combination of a first fluid including water, the crosslinkable component, the crosslinker, and the enzyme breaker, and having a total dissolved content A with formation water having a total dissolved content B which is higher than the total dissolved content A of the first fluid.

Dual-purpose additives that may be used as viscosifying agents and surface active agents in fluids, subterranean treatments and oilfield operations are provided. In one embodiment, the methods comprise: providing a treatment fluid comprising a base fluid and a polymeric dual-purpose additive comprising a base polymer comprising a plurality of monomer units, and one or more hydrophobic groups bonded to at least one of the monomer units; introducing the treatment fluid into at least a portion of a subterranean formation; and depolymerizing at least a portion of the dual-purpose additive to form one or more surface active fragments, each of the surface active fragments comprising one or more of the hydrophobic groups bonded to one or more of the monomer units.

Various embodiments disclosed relate to delayed crosslinking compositions or reaction products thereof for treatment of a subterranean formation. In various embodiments, the present invention provides a method of treating a subterranean formation including placing in a subterranean formation a subterranean treatment composition including at least one of a delayed crosslinking composition and a reaction product thereof. The delayed crosslinking composition includes a crosslinker including a functionality chosen from —B(OH).sub.2, —B.sup.−(OH).sub.2, —O—B(OH)—O—B(OH)—O—, —O—B(OH)—O—B.sup.−(OH)(—O—).sub.2, a salt thereof, an ester thereof, and a combination thereof. The delayed crosslinking composition also includes a glycol including at least one of a 1,2-diol and a 1,3-diol.

This disclosure provides drilling fluids and additives as well as fracturing fluids and additives that contain cellulose nanofibers and/or cellulose nanocrystals. In some embodiments, hydrophobic nanocellulose is provided which can be incorporated into oil-based fluids and additives. These water-based or oil-based fluids and additives may further include lignosulfonates and other biomass-derived components. Also, these water-based or oil-based fluids and additives may further include enzymes. The drilling and fracturing fluids and additives described herein may be produced using the AVAP® process technology to produce a nanocellulose precursor, followed by low-energy refining to produce nanocellulose for incorporation into a variety of drilling and fracturing fluids and additives.

Various embodiments disclosed relate to crosslinked polymers including sulfonic acid groups or salts or esters thereof as viscosifiers and fluid loss additives for subterranean treatment. In various embodiments, the present invention provides a method of treating a subterranean formation. The method includes placing in a subterranean formation a composition including a crosslinked viscosifier polymer including an ethylene repeating unit including an —S(O).sub.2OR.sup.1 group wherein at each occurrence R.sup.1 is independently chosen from —H, substituted or unsubstituted (C.sub.1-C.sub.20)hydrocarbyl, and a counterion.

The instant invention relates to a method for sealing a subterranean environment, wherein a polyurethane encapsulated polyamine is injected into the subterranean environment and is released in situ in the presence of a reactive species able to form a gel or a precipitate by a physical association and/or a chemical reaction with the released polyamine.

The invention relates to synthetic nanocompounds in the form of microparticles that allow major deformations before breaking and are especially useful for preparing low-density synthetic propping agents to be used in non-conventional oil and gas extraction processes (fracking). The invention also describes the process for obtaining said nanocompounds, propping agents and fracturing fluids for oil and gas extraction processes.

Crosslinked polymer additives that may be used as thinners and/or deflocculants in subterranean treatment fluids are provided. In one embodiment, the methods comprise: providing a treatment fluid comprising an aqueous base fluid, a viscosifying agent, and a crosslinked synthetic polymer that comprises a copolymer of at least a first monomer comprising 2-acrylamido-2-methylpropane sulfonic acid or any salt thereof, and a second monomer comprising an N-vinyl amide, and at least one crosslinking agent, wherein the average molecular weight of the crosslinked synthetic polymer is less than about 3,000,000 grams per mole; and introducing the treatment fluid into at least a portion of a well bore penetrating at least a portion of a subterranean formation.