A method of forming a barrier to overcome lost circulation in a subterranean formation. The method includes injecting a polymer-sand nanocomposite into one or more lost circulation zones in the subterranean formation where the polymer-sand nanocomposite is formed from sand mixed with a polymer hydrogel. Further, the polymer hydrogel includes a hydrogel polymer, an organic cross-linker, and a salt. The sand additionally comprises a surface modification. The associated method of preparing a polymer-sand nanocomposite lost circulation material for utilization in forming the barrier is provided.

The disclosed hydraulic fracturing fluid can include a liquid solvent, one or more surfactants, a proppant-forming compound, and one or more curing agents. When injected into a wellbore, the hydraulic fracturing fluid reacts to form proppant pillars in-situ under downhole conditions. The proppant pillars are capable of maintaining conductive fractures.

Disclosed are surface-modified nanoparticles and surfactants used in compositions and methods for enhancing hydro-carbon recovery from subterranean formations.

Coated proppants include a proppant particle, a surface copolymer layer surrounding the proppant particle, and a resin layer surrounding the surface copolymer layer. The surface copolymer layer includes a copolymer of at least two monomers chosen from styrene, methyl methacrylate, ethylene, propylene, butylene, imides, urethanes, sulfones, carbonates, and acrylamides, where the copolymer is crosslinked by divinyl benzene. The resin layer includes a cured resin. Methods of preparing the coated proppants include preparing a first mixture including at least one polymerizable material, an initiator, and a crosslinker including divinyl benzene; contacting the first mixture to a proppant particle to form a polymerization mixture; heating the polymerization mixture to cure the polymerizable material and form a polymer-coated particulate; preparing a second mixture including the polymer-coated substrate, an uncured resin, and a solvent; and adding a curing agent to the second mixture to cure the uncured resin and form the coated proppant.

A method for producing hydrocarbons within a reservoir includes (a) injecting an aqueous solution into the reservoir. The aqueous solution includes water and a thermally activated chemical species. The thermally activated chemical species is urea, a urea derivative, or a carbamate. The thermally activated chemical agent is thermally activated at or above a threshold temperature less than 200 C. In addition, the method includes (b) thermally activating the thermally activated chemical species in the aqueous solution during or after (a) at a temperature equal to or greater than the threshold temperature to produce carbon-dioxide and at least one of ammonia, amine, and alkanolamine within the reservoir. Further, the method includes (c) increasing the water wettability of the subterranean formation in response to the thermally activation in (b). Still further, the method includes (d) waterflooding the reservoir with water after (a), (b) and (c).

A method includes injecting an aqueous-based injection fluid into a wellbore at a first temperature, where the aqueous-based injection fluid includes phase-changing nanodroplets having a liquid core and a shell. The method also includes exposing the phase-changing nanodroplets to a second temperature in the wellbore that is greater than or equal to a boiling point of the liquid core to change a liquid in the liquid core to a vapor phase and expand the phase-changing nanodroplets, thus removing debris from the wellbore and surrounding area.

A method for controlling fluid loss into the pores of an underground formation during fracturing operations is provided. Nanoparticles are added to the fracturing fluid to plug the pore throats of pores in the underground formation. As a result, the fracturing fluid is inhibited from entering the pores. By minimizing fluid loss, higher fracturing fluid pressures are maintained, thereby resulting in more extensive fracture networks. Additionally, nanoparticles minimize the interaction between the fracturing fluid and the formation, especially in water sensitive formations. As a result, the nanoparticles help maintain the integrity and conductivity of the generated, propped fractures.

Cementing compositions containing a hydraulic cement, halloysite nanoparticles, and silica flour. The cementing compositions may optionally include other additives such as a friction reducer, a defoamer, and a fluid loss additive. Cement samples made therefrom and methods of producing such cement samples are also specified. The addition of halloysite nanoparticles and silica flour provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to CO.sub.2 and salinity) to the cement, making them suitable cementing material for oil and gas wells.

Synthesizing Janus material including forming a lamellar phase having water layers and organic layers, incorporating nanosheets and a functional agent into the lamellar phase, and attaching the functional agent to the nanosheets in the lamellar phase to form Janus nanosheets.

Synthesizing Janus material including forming a lamellar phase having water layers and organic layers, incorporating nanosheets and a functional agent into the lamellar phase, and attaching the functional agent to the nanosheets in the lamellar phase to form Janus nanosheets.