Activating a reaction of a sealant, such as cement, with a fiber optic cable, the reaction causing hardening of the sealant. The sealant may be used in wellbore cementing operations to cement a casing in a wellbore. The fiber optic cable may be deployed by attaching it to the outside of a casing during insertion into the wellbore. The activation of the sealant can be via thermal or optical initiation in order to causing a hydration reaction or polymerization.

A vinyl alcohol copolymer, wherein the vinyl alcohol copolymer includes a vinyl alcohol unit and a constituent unit derived from an unsaturated monomer (A), the unsaturated monomer (A) is at least one selected from the group consisting of an unsaturated carboxylic acid, a salt thereof, an anhydride thereof, and an alkyl ester thereof, a content of the constituent unit derived from the unsaturated monomer (A) with respect to total constituent units of the vinyl alcohol copolymer is 1.00 mol % or more and 5.00 mol % or less, and 70 mol % or more of the constituent unit derived from the unsaturated monomer (A) forms a lactone ring structure.

In accordance with one or more embodiments of the present disclosure, a drilling fluid may include a base fluid and one or more formaldehyde-based resins. The drilling fluid may further comprise one or more water-soluble acid catalyst precursors or the reaction products of such water-soluble acid catalyst precursors. The base fluid may include an aqueous or non-aqueous solution. The present disclosure also describes sealed subterranean petroleum formations that include such drilling fluids and methods for sealing subterranean wellbores by utilizing such drilling fluids.

Embodiments of the disclosure include swellable smart gel sealants and methods of using smart gel sealants. In certain embodiments, the smart gel sealants reversibly swell when exposed to a certain trigger, such as carbonic acid and/or sulfuric acid. In specific embodiments, the smart gel is comprised within a cement composition.

A method may include introducing a resin treatment fluid into a wellbore, the resin treatment fluid including a resin, a hardening agent, and a neutron contrasting agent; and allowing the resin treatment fluid to set to form a hardened mass.

A method may include introducing a resin treatment fluid into a wellbore, the resin treatment fluid including a resin, a hardening agent, and a neutron contrasting agent; and allowing the resin treatment fluid to set to form a hardened mass.

A method may include: introducing a silane based aqueous soluble resin into a wellbore, wherein the silane based aqueous soluble resin comprises a glycidyl alkoxy silane containing resin and an amino alkoxy silane hardener. The silane based aqueous soluble resin may include 3-glycidoxypropyl trimethoxy silane and n-(3-(trimethoxysilyl)propyl)ethylenediamine.

A method may include: introducing a silane based aqueous soluble resin into a wellbore, wherein the silane based aqueous soluble resin comprises a glycidyl alkoxy silane containing resin and an amino alkoxy silane hardener. The silane based aqueous soluble resin may include 3-glycidoxypropyl trimethoxy silane and n-(3-(trimethoxysilyl)propyl)ethylenediamine.

Embodiments of the disclosure include swellable smart gel sealants and methods of using smart gel sealants. In certain embodiments, the smart gel sealants reversibly swell when exposed to a certain trigger, such as temperature or pH. In specific embodiments, the smart gel is disposed within voids in a well and triggered to swell in order to seal the voids. One application of the smart gel sealant is to seal the casing of a well against the leakage of gas, such as H.sub.2S.

Embodiments of the disclosure include swellable smart gel sealants and methods of using smart gel sealants. In certain embodiments, the smart gel sealants reversibly swell when exposed to a certain trigger, such as temperature or pH. In specific embodiments, the smart gel is disposed within voids in a well and triggered to swell in order to seal the voids. One application of the smart gel sealant is to seal the casing of a well against the leakage of gas, such as H.sub.2S.