Methods for treating a hydrocarbon-containing formation may include preheating a gelant that contains a crosslinkable polymer, one or more crosslinking agents, and an aqueous fluid; and injecting the gelant into the formation, wherein the gelant forms a gel in the formation. Methods for enhanced oil recovery may include preheating a gelant that contains a crosslinkable polymer, one or more crosslinking agents, and an aqueous fluid; injecting the gelant into a high permeability zone of a hydrocarbon-containing formation, wherein the gelant forms a gel; and stimulating a flow of hydrocarbons from a low permeability zone of the hydrocarbon-containing formation.

Disclosed herein is a crosslinked HPG fluid system using a very low concentration of HPG polymer. The fluid system is able to be used at low HPG concentrations while maintaining stable viscosity for over two hours at elevated temperatures.

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.

An aqueous caustic composition comprising: a caustic component; an alkanolamine additive adapted to provide an extended buffering effect to the caustic composition when such is exposed to acid; and water. Uses and methods of using such compositions are also disclosed.

A treatment fluid system for reducing permeability of high permeability zones in a subterranean reservoir formation comprising a fluid composition comprising a nano-crosslinker, the nano-crosslinker comprising a nanomaterial, and a crosslinker, wherein the crosslinker comprises a chemical group selected from the group consisting of carbonyl, sulfhydryl, amine and imine, wherein the nano-crosslinker is produced by a method selected from the group consisting of pre-treating the nanomaterial with the crosslinker such that the crosslinker has been functionalized onto the nanomaterial, embedding the crosslinker on the nanoparticle, grafting the crosslinker onto the nanomaterial, and coating the crosslinker on the nanomaterial, a base polymer, and a base fluid, the base fluid operable to suspend the fluid composition, wherein the base fluid comprises water, wherein the treatment fluid system is operable to reduce permeability of a high permeability zone in the subterranean reservoir formation.

The invention is directed to delayed gelation agents comprising a degradable polymeric cage containing therein one or more gelation agents. The cage degrades in situ, e.g, in an oil reservoir, thus releasing the gelation agent(s), which can then crosslink second polymers in situ to form a gel.

Disclosed herein are compositions and methods for delaying crosslinking in injectable compositions for hydraulic fracturing and related applications. The compositions and methods are effective in injectable compositions comprising or substantially excluding dissolved reactive species. The compositions and methods provide delayed crosslinking at high temperatures and pressures, such as those encountered by hydraulic fracturing compositions injected into subterranean environments. Compositions include injectable solutions comprising a competing agent that is the reaction product of a dialdehyde having 2 to 4 carbon atoms with a non-polymeric cis-hydroxyl compound. Also provided are methods of making and using delayed-crosslinking compositions comprising crosslinker compositions containing zirconium complexes and the competing agents.

An aqueous caustic composition comprising: a caustic component; an amino acid additive adapted to provide an extended buffering effect to the caustic composition when such is exposed to an acid; and water, wherein the caustic component and the amino acid additive are present in a molar ratio ranging from 15:1 to 5:1. Methods of using such compositions are also disclosed.

Methods of treating a subterranean formation are disclosed that include placing a treatment fluid into a subterranean formation, the treatment fluid containing a one or more polymers capable of consolidating to form a polymeric structure at a downhole location. Also disclosed are treatment fluids including a polymeric structure for treating a subterranean formation.

A system and process for defining, blending and monitoring fresh water with subterranean produced formation fluids, with particular constituents of the blended waters being controlled for proper use in gel-type hydraulic fracturing operations. On-site measurements and calculations of clay stabilization replacement, through a Potassium Chloride (KCl) Equivalency calculation, provide feedback on water constituent adjustments that may be needed just prior to the gel-based hydraulic fracturing process. This assures adequate gel cross-linking times, delayed gel cross-linking times, and clay stabilization in the formation to be fractured.