Nano-sized metal silica oxide carriers capable of delivering a well treatment additive for a sustained or extended period of time in the environment of use, methods of making the nanoparticles, and uses thereof are described herein. The nanoparticles include an additive loaded in a silica oxide/metal nanoparticle. The metal can be a Column 2 metal, a Column 14 metal, or transition metal.

A thermochemical soap stick, system, and method for unloading liquid from a well, the thermochemical soap stick having thermochemical reagents and to be provided into a wellbore in a subterranean formation, the thermochemical soap stick to dissolve in the liquid giving a thermochemical reaction to generate gas to foam the liquid, and displacing the liquid from the wellbore via pressure of the subterranean formation.

A polymer gel may comprise a polymer gel base material and superparamagnetic nanoparticles. At least 25 wt. % of the superparamagnetic nanoparticles may have diameters in a first size range between a first diameter and a second diameter. At least 25 wt. % of the superparamagnetic nanoparticles may have diameters in a second size range between a third diameter and a fourth diameter. The Brownian relaxation time of the portion of the superparamagnetic nanoparticles in the first size range may be at least 5 times the Neel relaxation time of the portion of the superparamagnetic nanoparticles in the first size range. The Neel relaxation time of the portion of the superparamagnetic nanoparticles in the second size range may be at least 5 times the Brownian relaxation time of the portion of the superparamagnetic nanoparticles in the second size range. Methods for monitoring gel integrity in a wellbore are further included.

A well cleanup process involves removing an impermeable filter cake from a formation face with thermochemical and chelating agents to allow formation fluids to flow from a reservoir to a wellbore. The method may be used with oil and water-based drilling fluids with varied weighting agents, e.g., bentonite, calcium carbonate, or barite. Such thermochemical agents may involve two salts, e.g., NO.sub.2.sup.− and NH.sub.4.sup.+, which, when mixed together, can generate pressure and heat, in addition to hot H.sub.2O and/or N.sub.2. For example, the thermochemical agents may comprise Na.sup.+, K.sup.+, Li.sup.+, Cs.sup.+, Mg.sup.2+, Ca.sup.2+, and/or Ba.sup.2+ with NO.sub.2.sup.− and NH.sub.4.sup.+ with F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, CO.sub.3.sup.2−, NO.sub.3.sup.−, ClO.sub.4.sup.−, and/or .sup.−OH. The thermochemical agents in combination with a chelator such as EDTA can removed the filter cake after 6 hours with a removal efficiency of 89 wt % for the barite filter cake in water based drilling fluid, exploiting the generation of a pressure pulse and heat which may disturb the filter cake and/or enhance barite dissolution and polymer degradation.

Lost circulation materials may include pluralities of ceramic spheres having a size distribution in a range of from about 5 mm to about 25 mm and such that the lost circulation materials are porous and permeable. Methods of eliminating or reducing lost circulation from a well having a loss zone may include introducing the porous and permeable lost circulation materials into the well such that a porous and permeable flow barrier is created in the loss zone, wherein the porous and permeable flow barrier may prevent whole mud loss while drilling and allows hydrocarbon production after completion of the well. Carrier fluids may include water, viscosifiers, fluid loss additives, weighting agents, lost circulation materials containing pluralities of ceramic spheres having a size distribution in a range of from about 5 mm to about 25 mm.

A thermochemical soap stick, system, and method for unloading liquid from a well, the thermochemical soap stick having thermochemical reagents and to be provided into a wellbore in a subterranean formation, the thermochemical soap stick to dissolve in the liquid giving a thermochemical reaction to generate gas to foam the liquid, and displacing the liquid from the wellbore via pressure of the subterranean formation.

Disclosed herein are compositions and methods for reducing fluid loss in a well bore, methods for wellbore strengthening and increasing the integrity of the borehole of an oil or gas well. Also disclosed are methods for artificially increasing the temperature of a subsurface formation in the wellbore to increase the apparent wellbore strength. The mechanism for accomplishing this revolves around increasing fracture propagation pressure by actively manipulating thermal wellbore stresses.

An additive capable of suppressing generation of free water from a cement slurry even under a high temperature environment of 150° C. or more and a silica-based additive that suppresses, in a cement slurry for cementing in oil fields and gas oil fields, free water under high temperature and high pressure environments of 100° C. or more, the silica-based additive containing an aqueous silica sol containing nanosilica particles with a true density of 2.15 g/cm.sup.3 or more and less than 2.30 g/cm.sup.3, and a cement slurry for cementing that contains the silica-based additive.

A lost-circulation material including a mixture of an aqueous colloidal dispersion and fatty acid. The aqueous colloidal dispersion includes silica nanoparticles and has a pH of at least 8. Combining the colloidal dispersion and the fatty acid initiates gelation of the lost-circulation material when the pH of the lost-circulation material is less than 8 and a temperature of the lost-circulation material is in a range of 5° C. to 300° C. Sealing an opening in a portion of a wellbore or a portion of a subterranean formation in which the wellbore is formed may include providing the aqueous colloidal dispersion and the fatty acid to the wellbore, mixing the colloidal dispersion and the fatty acid to yield the lost-circulation material, initiating gelation of the lost-circulation material, and solidifying the lost-circulation material in the wellbore to yield a set gel.

Disclosed herein are degradable diverter materials comprising a polyacrylate compound. In particular, the degradable diverter material may be a particulate with each individual particle being having a polyacrylate compound and optionally at least one inert filler. The degradable diverter material may be introduced into a wellbore penetrating a subterranean formation. The degradable diverter material may then be allowed to divert at least a portion of fluid present downhole, the fluid being introduced from the surface or already present downhole. The degradable diverter material can then be allowed to at least partially degrade via dissolution.