A well treatment composition for use in a hydrocarbon-bearing reservoir comprising a reversible aminal gel composition is disclosed. The reversible aminal gel composition includes a liquid precursor composition. The liquid precursor composition is operable to remain in a liquid state at about room temperature. The liquid precursor composition comprises an organic amine composition; an aldehyde composition; a polar aprotic organic solvent; and a metal salt composition with valence 3, 4, or 5. The liquid precursor composition transitions from the liquid state to a gel state responsive to an increase in temperature in the hydrocarbon-bearing reservoir. The gel state is stable in the hydrocarbon-bearing reservoir at a temperature similar to a temperature of the hydrocarbon-bearing reservoir, and the gel state is operable to return to the liquid state responsive to a change in the hydrocarbon-bearing reservoir selected from the group consisting of: a decrease in pH in the hydrocarbon-bearing reservoir and an addition of excess metal salt composition in the hydrocarbon-bearing reservoir.

A nanosilica containing fluid system for shale stabilization in a shale formation. The nanosilica containing fluid system comprising a functionalized nanosilica composition operable to react with shale at the surface of the shale formation to form a barrier on the shale formation. The functionalized nanosilica composition comprising a nanosilica particle, the nanosilica particle having a mean diameter, and a functionalization compound, the functionalization compound appended to the surface of the nanosilica particle. And an aqueous-based fluid, the aqueous-based fluid operable to carry the functionalized nanosilica composition into the shale formation. The functionalization compound is an amino silane. The aqueous-based fluid is selected from the group consisting of water, deionized water, sea water, brine, and combinations thereof.

Nano-sized clay minerals enhance the viscosity of aqueous fluids that have increased viscosity due to the presence of viscoelastic surfactants (VESs). In one non-limiting theory, the nano-sized phyllosilicate mineral viscosity enhancers associate, link, connect, or relate the VES elongated micelles into associations thereby increasing the viscosity of the fluid, possibly by mechanisms involving chemisorption or surface charge attractions. The nano-sized phyllosilicate mineral particles, also called clay mineral nanoparticles, may have irregular surface charges. The higher fluid viscosity is beneficial to crack the formation rock during a fracturing operation, to reduce fluid leakoff, and to carry high loading proppants to maintain the high conductivity of fractures.

Nano-sized clay minerals enhance the viscosity of aqueous fluids that have increased viscosity due to the presence of viscoelastic surfactants (VESs). In one non-limiting theory, the nano-sized phyllosilicate mineral viscosity enhancers associate, link, connect, or relate the VES elongated micelles into associations thereby increasing the viscosity of the fluid, possibly by mechanisms involving chemisorption or surface charge attractions. The nano-sized phyllosilicate mineral particles, also called clay mineral nanoparticles, may have irregular surface charges. The higher fluid viscosity is beneficial to crack the formation rock during a fracturing operation, to reduce fluid leakoff, and to carry high loading proppants to maintain the high conductivity of fractures.

A method of treating a lost circulation zone in a wellbore includes contacting an accelerant composition comprising triethanolamine with a cement composition in the lost circulation zone, the cement composition comprising at least: from 1 weight percent (wt. %) to 90 wt. % cement precursor based on the total weight of the cement composition; and from 5 wt. % to 70 wt. % water based on the total weight of the cement composition; where a weight ratio of triethanolamine to the cement precursor is from 0.1 percent (%) to 60%; and curing the cement composition in the lost circulation zone to form a cured cement, where the triethanolamine accelerates the curing rate of the cement composition and the cured cement seals the lost circulation zone.

Drilling fluid compositions include invert emulsion fluids having an oleaginous phase, an aqueous phase, and an emulsifier composition that includes an ethoxylated alcohol compound and a polyaminated fatty acid compound. The ethoxylated alcohol compound has the formula R.sup.1—(OCH.sub.2CH.sub.2).sub.n—OH, where R.sup.1 is a hydrocarbyl group having from 8 to 22 carbon atoms and n is from 1 to 8. The ethoxylated alcohol compound has a Hydrophilic-Lipophilic Balance (HLB) of less than or equal to 6. The polyaminated fatty acid compound has the formula R.sup.2—CO—NH—CH.sub.2—CH.sub.2—N(COR.sup.2)—CH.sub.2—CH.sub.2—NH—CO—R.sup.3, where R.sup.2 is a hydrocarbyl group having from 1 to 20 carbon atoms and R.sup.3 is a hydrocarbyl group having from 1 to 10 carbon atoms or an alkylene carboxylate group having formula —R.sup.4—COOH, where R.sup.4 is a saturated or unsaturated hydrocarbylene having from 1 to 10 carbon atoms. Methods of drilling wells include operating a drill in a wellbore in the presence of drilling fluid compositions.

The present invention relates to a method for increasing oil recovery from an oil-bearing formation including the following successive stages of treating the formation: injecting an invert emulsion in a volume of 3-5 m.sup.3/m of perforated interval thickness followed by squeezing down an acidic composition or a composition containing a nonionic surfactant in a volume of 2-3 m.sup.3/m of perforated interval thickness to the formation, injecting a highly stable direct emulsion containing a colloidal solution of silicon dioxide nanoparticles in a volume of 3-7 m.sup.3/m of perforated interval thickness followed by squeezing down a liquid from a reservoir pressure maintenance system to the formation.

A method and a system for preventing water production in subterranean formations are provided. An exemplary system disclosed a water shutoff material for a wellbore. The water shutoff material includes a gel formed from an acidic suspension of nanosilica particles and an activator.

A chemical gel system having a polymer and a silicon oxide Janus nanosheets crosslinker for treating thief zones in carbonate formations. The polymer and silicon oxide Janus nanosheets crosslinker may form a crosslinked polymer gel to reduce or prevent water production via thief zones during hydrocarbon production. The silicon oxide Janus nanosheets crosslinker includes a first side having negatively charged functional groups and a second side having amines. The negatively charged functional groups may include negatively charged oxygen groups and hydroxyl groups. Methods of reducing water production in a thief zone using the silicon oxide Janus nanosheets crosslinker and methods of manufacturing the silicon oxide Janus nanosheets crosslinker are also provided.

A chemical gel system having a polymer and a graphene oxide Janus nanosheets crosslinker for treating thief zones in carbonate formations. The polymer and graphene oxide Janus nanosheets crosslinker may form a crosslinked polymer gel to reduce or prevent water production via thief zones during hydrocarbon production. The graphene oxide Janus nanosheets crosslinker includes a first side having negatively charged functional groups and a second side having amines. The negatively charged functional groups may include carboxyl groups, negatively charged oxygen groups, and hydroxyl groups. Methods of reducing water production in a thief zone using the graphene oxide Janus nanosheets crosslinker and methods of manufacturing the graphene oxide Janus nanosheets crosslinker are also provided.