Abstract: A plasmonic substrate includes a base, a metallic film on the base, and a semiconducting photocatalyst on the metallic film. A method for producing a plasmonic substrate includes depositing a first metal layer having a thickness ranging from 10 to 200 nm and having a first metal through a physical vapor deposition technique onto a base, depositing a second metal layer having a second metal through a physical vapor deposition technique onto the first metal layer forming a multilayered metal template, immersing the multilayered metal template into a solution having a salt or complex of the second metal for a period of time forming a metallic film, and depositing a semiconducting photocatalyst on the metallic film. A method of catalyzing hydrogen production includes immersing a plasmonic substrate in a photocatalytic solution, exposing the plasmonic substrate to light, and generating hydrogen at a surface of the semiconducting photocatalyst.

Abstract: A fluid control device includes a housing, a fluid channel defined within the housing, the fluid channel having an inlet, and a restriction assembly. The restriction assembly includes a cantilever device disposed within the fluid channel and defining a restricted fluid path, the cantilever device configured to deform to reduce an area of the restricted fluid path and restrict a flow rate of fluid flowing therethrough based on a property of the fluid.

Abstract: A system for controlling a flow of fluid includes a flow control device having a fluid channel configured to transport a fluid between a subterranean region and a borehole conduit, a resonant sensing assembly including a resonator body disposed in fluid communication with the fluid channel, and a controller configured to cause the resonator body to vibrate according to an expected resonance frequency of the resonator body. The system also includes a processing device configured to acquire a measurement signal generated by the resonator body, estimate a property of the fluid based on the measurement signal, and control a flow of the fluid through the flow control device based on the property of the fluid.

Abstract: A method of controlling lost circulation includes introducing into a wellbore a lost circulation fluid comprising: an external oil phase, an internal aqueous phase, an emulsifier, a wetting agent, a magnesia sealant, and a; retarder; contacting the lost circulation fluid with a lost circulation zone; and forming a plug adjacent the lost circulation zone by reacting the magnesia sealant with water at a wellbore temperature, thereby reducing fluid loss into the lost circulation zone.

Abstract: A treatment fluid comprises: a base fluid; a viscoelastic surfactant gelling agent and hydrophobic nanoparticles comprising metallic nanoparticles that are surface modified with C6-30 aliphatic groups. The treatment fluid is a fracturing fluid, a completion fluid, a gravel pack fluid, a fluid loss pill, a lost circulation pill, a diverter fluid, a foamed fluid, a stimulation fluid and the like.

Abstract: A fluid control device includes a housing, a fluid channel defined within the housing, the fluid channel having an inlet, and a restriction assembly. The restriction assembly includes a cantilever device disposed within the fluid channel and defining a restricted fluid path, the cantilever device configured to deform to reduce an area of the restricted fluid path and restrict a flow rate of fluid flowing therethrough based on a property of the fluid.

Abstract: A system for controlling a flow of fluid includes a flow control device having a fluid channel configured to transport a fluid between a subterranean region and a borehole conduit, a resonant sensing assembly including a resonator body disposed in fluid communication with the fluid channel, and a controller configured to cause the resonator body to vibrate according to an expected resonance frequency of the resonator body. The system also includes a processing device configured to acquire a measurement signal generated by the resonator body, estimate a property of the fluid based on the measurement signal, and control a flow of the fluid through the flow control device based on the property of the fluid.

Abstract: A viscoelastic surfactant treatment fluid comprises an aqueous base fluid an inorganic salt, the inorganic salt being present in an amount of greater than about 5 wt. % based on the total weight of the treatment fluid; a viscoelastic surfactant gelling agent effective to gel the aqueous base fluid by forming a plurality of micelles; and a cationic polymer additive associated with the micelles via electrostatic interactions.

Abstract: A viscoelastic surfactant treatment fluid comprises an aqueous base fluid an inorganic salt, the inorganic salt being present in an amount of greater than about 5 wt. % based on the total weight of the treatment fluid; a viscoelastic surfactant gelling agent effective to gel the aqueous base fluid by forming a plurality of micelles; and a cationic polymer additive associated with the micelles via electrostatic interactions.

Abstract: A method of breaking the viscosity of a treatment fluid comprises: adding hydrophobic nanoparticles to a treatment fluid comprising a base fluid and a viscoelastic surfactant gelling agent, the hydrophobic nanoparticles comprising metallic nanoparticles that are surface modified with C6-30 aliphatic groups, wherein the hydrophobic nanoparticles are added in an amount effective to decrease the viscosity of the treatment fluid as compared to a treatment fluid absent the hydrophobic nanoparticles.

Abstract: A method of breaking the viscosity of a treatment fluid comprises: adding hydrophobic nanoparticles to a treatment fluid comprising a base fluid and a viscoelastic surfactant gelling agent, the hydrophobic nanoparticles comprising metallic nanoparticles that are surface modified with C6-30 aliphatic groups, wherein the hydrophobic nanoparticles are added in an amount effective to decrease the viscosity of the treatment fluid as compared to a treatment fluid absent the hydrophobic nanoparticles.

Abstract: A method of treating a subterranean formation penetrated by a well comprises combining an aqueous base fluid, a viscoelastic surfactant gelling agent, two or more types of the following nanoparticles: an alkaline earth metal oxide; an alkaline earth metal hydroxide; a transition metal oxide; or a transition metal hydroxide to form a treatment fluid, and pumping the treatment fluid into the well, wherein the weight ratio of the two or more types of the nanoparticles is selected such that the treatment fluid has an improved fluid efficiency as compared to an otherwise identical reference fluid except for comprising only one type of the nanoparticles selected from an alkaline earth metal oxide; an alkaline earth metal hydroxide; a transition metal oxide; and a transition metal hydroxide.

Abstract: A method of breaking the viscosity of a treatment fluid comprises: adding hydrophobic nanoparticles to a treatment fluid comprising a base fluid and a viscoelastic surfactant gelling agent, the hydrophobic nanoparticles comprising metallic nanoparticles that are surface modified with C6-30 aliphatic groups, wherein the hydrophobic nanoparticles are added in an amount effective to decrease the viscosity of the treatment fluid as compared to a treatment fluid absent the hydrophobic nanoparticles.

Abstract: A method of treating a subterranean formation penetrated by a well comprises combining an aqueous base fluid, a viscoelastic surfactant gelling agent, two or more types of the following nanoparticles: an alkaline earth metal oxide; an alkaline earth metal hydroxide; a transition metal oxide; or a transition metal hydroxide to form a treatment fluid, and pumping the treatment fluid into the well, wherein the weight ratio of the two or more types of the nanoparticles is selected such that the treatment fluid has an improved fluid efficiency as compared to an otherwise identical reference fluid except for comprising only one type of the nanoparticles selected from an alkaline earth metal oxide; an alkaline earth metal hydroxide; a transition metal oxide; and a transition metal hydroxide.

Abstract: A method of synthesizing branched gold nanoparticles is described, starting from an aqueous solution of gold nanoparticle spherical seeds, which is subjected to a growth treatment with an aqueous solution comprising hydroxylamine or a salt thereof as a reducing agent and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as an agent that directs the shape of the nanostructure, and by subsequent addition of an aqueous solution of chloroauric acid (HAuCl4). The structural features and the properties of the branched gold nanoparticles obtained by the method of the invention are also described.

Abstract: A method of synthesizing branched gold nanoparticles is described, starting from an aqueous solution of gold nanoparticle spherical seeds, which is subjected to a growth treatment with an aqueous solution comprising hydroxylamine or a salt thereof as a reducing agent and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) as an agent that directs the shape of the nanostructure, and by subsequent addition of an aqueous solution of chloroauric acid (HAuCl4). The structural features and the properties of the branched gold nanoparticles obtained by the method of the invention are also described.