Abstract: A method of determining a concentration of hydrogen sulfide in a fluid comprises exposing a sensor to the fluid, the sensor comprising a pair of electrodes defining a gap therebetween and a sensing material bridging the gap between the electrodes, measuring a value of an electrical parameter of the sensor at an applied frequency of greater than about 10 kHz and a voltage of less than about 1.0 volt when the sensor is exposed to the fluid, and determining the concentration of hydrogen sulfide in the fluid based at least in part on the measured value of the electrical parameter. Related apparatuses and methods are also disclosed.

Abstract: A method of treating a fluid in a subterranean formation comprises injecting a fluid into the subterranean formation, the fluid containing dissolved oxygen; contacting the fluid with an oxygen removal device, the oxygen removal device comprising an anode, a cathode comprising metallic nanoparticles loaded on a support, an ion exchange membrane disposed between, and electrically separating the anode and the cathode, and a power source electrically coupled to the anode and the cathode; and reducing the amount of the dissolved oxygen in the fluid.

Abstract: A method and apparatus for estimating a concentration of chemicals in a fluid flowing in a fluid passage is disclosed. A sample of the fluid is placed on a substrate comprising a first layer of carbon nanotubes and a second layer of metal nanowires. An energy source radiates the fluid sample with electromagnetic radiation at a selected energy level, and a detector measures an energy level of radiation emitted from the fluid sample in response to the electromagnetic radiation. A processor determines a Raman spectrum of the fluid sample from the energy level of the emitted radiation and estimates the concentration of a selected chemical in the fluid sample based on the Raman spectrum.

Abstract: A suspension for removing hydrocarbons from a subterranean formation includes a fluid comprising at least one of water, brine, steam, carbon dioxide, a light hydrocarbon, and an organic solvent; and a plurality of nanoparticles dispersed with the fluid. Nanoparticles of the plurality comprise silica and carbon. A method includes forming a plurality of nanoparticles and dispersing the plurality of nanoparticles with a fluid to form a suspension comprising the nanoparticles. A method of recovering a hydrocarbon material includes introducing a suspension into a subterranean formation containing hydrocarbons, forming a stabilized emulsion of the suspension and the hydrocarbons within the subterranean formation; and removing the emulsion from the subterranean formation. The suspension comprises a plurality of nanoparticles, and at least some nanoparticles of the plurality comprise silica and carbon.

Abstract: A method of determining a property within a subterranean formation comprises introducing silica nanoparticles into a well; obtaining a sample of a fluid produced from the well; and analyzing the sample for presence of the silica nanoparticles, wherein the silica nanoparticles comprise a core, a donor chromophore, an acceptor chromophore, and an outer silica shell; the donor chromophore and the acceptor chromophore being selected such that an emission spectrum of the donor chromophore overlaps with an absorption spectrum of the acceptor chromophore.

Abstract: A suspension for removing hydrocarbons from a subterranean formation includes a fluid comprising at least one of water, brine, steam, carbon dioxide, a light hydrocarbon, and an organic solvent; and a plurality of nanoparticles dispersed with the fluid. Nanoparticles of the plurality comprise silica and carbon. A method includes forming a plurality of nanoparticles and dispersing the plurality of nanoparticles with a fluid to form a suspension comprising the nanoparticles. A method of recovering a hydrocarbon material includes introducing a suspension into a subterranean formation containing hydrocarbons, forming a stabilized emulsion of the suspension and the hydrocarbons within the subterranean formation; and removing the emulsion from the subterranean formation. The suspension comprises a plurality of nanoparticles, and at least some nanoparticles of the plurality comprise silica and carbon.

Abstract: A method of determining a concentration of hydrogen sulfide in a fluid comprises exposing a sensor to the fluid, the sensor comprising a pair of electrodes defining a gap therebetween and a sensing material bridging the gap between the electrodes, measuring a value of an electrical parameter of the sensor at an applied frequency of greater than about 10 kHz and a voltage of less than about 1.0 volt when the sensor is exposed to the fluid, and determining the concentration of hydrogen sulfide in the fluid based at least in part on the measured value of the electrical parameter. Related apparatuses and methods are also disclosed.

Abstract: A system and method for estimating a concentration of monoethanolamine (MEA) in a fluid. A substrate for supporting a sample of the fluid during testing includes a carbon nanotube mat layer, a silver nanowire layer disposed on the carbon nanotube mat layer, and a chemical enhancer layer disposed on the silver nanowire layer. A sample of the fluid is placed on the substrate, and the fluid sample is radiated with electromagnetic radiation at a selected energy level. A detector measures a Raman spectrum emitted from the sample in response to the electromagnetic radiation. A processor estimates the concentration of MEA in the sample from the Raman spectrum and adds a corrosion inhibitor to the fluid in an amount based on the estimated concentration of MEA to reduce the concentration of MEA in the fluid.

Abstract: Methods of determining a pH of a wellbore fluid within a wellbore in communication with a subterranean formation comprise introducing carbon quantum dots into a wellbore fluid, exposing the wellbore fluid to radiation from an electromagnetic radiation source, and measuring at least one fluorescence property of the carbon quantum dots within the wellbore fluid to determine a pH of the wellbore fluid. Related methods of determining a pH of a fluid within a wellbore extending through a subterranean formation are also disclosed.

Abstract: A filter membrane includes carbon nanotubes and carbon nitride nanoparticles. Inter-particle atomic interactions between the carbon nanotubes and the carbon nitride nanoparticles bind the carbon nanotubes and the carbon nitride nanoparticles together. A filter cartridge includes such a filter membrane disposed within an outer housing between a fluid inlet and a fluid outlet such that fluid passing through the outer housing between the fluid inlet and the fluid outlet passes through the filter membrane. Such filter membranes may be formed by dispersing carbon nanotubes and carbon nitride nanoparticles in a liquid to form a suspension, and passing the suspension through a filter to deposit the nanotubes and nanoparticles on the filter. Liquid may be filtered by causing the liquid to pass through such a filter membrane.

Abstract: A method of making a thin film substrate involves exposing carbon nanostructures to a crosslinker to crosslink the carbon nanostructures. The crosslinked carbon nanostructures are recovered and disposed on a support substrate. A thin film substrate includes crosslinked carbon nanostructures on a support substrate. The crosslinked carbon nanostructures have a crosslinker between the carbon nanostructures. A method of performing surface enhanced Raman spectroscopy (SERS) on a SERS-active analyte involves providing a SERS-active analyte on such a thin film substrate, exposing the thin film substrate to Raman scattering, and detecting the SERS-active analyte.

Abstract: Devices and methods for detecting chemicals are disclosed. A device configured for use in a wellbore includes a sensor including a quantum tunneling composite (QTC) material configured to exhibit a change in electrical resistance responsive to the sensor contacting a target chemical. The sensor includes electrical resistance measuring circuitry operably coupled to the QTC material and configured to measure the electrical resistance of the QTC material and output a sensor signal indicating the electrical resistance. A method comprises deploying the sensor into the wellbore, measuring the electrical resistance of the QTC material, and determining the presence of the target chemical responsive to detecting changes in the electrical resistance of the QTC material. Another method includes selecting at least one of the QTC material and an active material to interact with a target wellbore chemical to change the electrical resistance of the QTC material.

Abstract: A system and method for estimating a concentration of monoethanolamine (MEA) in a fluid. A substrate for supporting a sample of the fluid during testing includes a carbon nanotube mat layer, a silver nanowire layer disposed on the carbon nanotube mat layer, and a chemical enhancer layer disposed on the silver nanowire layer. A sample of the fluid is placed on the substrate, and the fluid sample is radiated with electromagnetic radiation at a selected energy level. A detector measures a Raman spectrum emitted from the sample in response to the electromagnetic radiation. A processor estimates the concentration of MEA in the sample from the Raman spectrum and adds a corrosion inhibitor to the fluid in an amount based on the estimated concentration of MEA to reduce the concentration of MEA in the fluid.

Abstract: A method of cementing a wellbore penetrating a subterranean formation comprises: injecting into the wellbore a cementing composition comprising: a ductility modifying agent comprising one or more of the following: an ionomer; a functionalized carbon; a metallic fiber; or a polymeric fiber; a cementitious material; an aggregate; and an aqueous carrier.

Abstract: A method of analyzing a selected refinery chemical at a low concentration comprises contacting a sample with functionalized metallic nanoparticles that contain metallic nanoparticles functionalized with a functional group comprising a cyano group, a thiol group, a carboxyl group, an amino group, a boronic acid group, an aza group, an ether group, a hydroxyl group, or a combination comprising at least one of the foregoing; radiating the sample contacted with the functionalized metallic nanoparticles with electromagnetic radiation at a selected energy level; measuring a Raman spectrum emitted from the sample; and determining the presence or a concentration of a selected refinery chemical in the sample from the Raman spectrum.

Abstract: Room temperature electrochemical methods to deposit thin films of chalcogenide glasses.

Abstract: A system and method for estimating a concentration of monoethanolamine (MEA) in a fluid. A substrate for supporting a sample of the fluid during testing includes a carbon nanotube mat layer, a silver nanowire layer disposed on the carbon nanotube mat layer, and a chemical enhancer layer disposed on the silver nanowire layer. A sample of the fluid is placed on the substrate, and the fluid sample is radiated with electromagnetic radiation at a selected energy level. A detector measures a Raman spectrum emitted from the sample in response to the electromagnetic radiation. A processor estimates the concentration of MEA in the sample from the Raman spectrum and adds a corrosion inhibitor to the fluid in an amount based on the estimated concentration of MEA to reduce the concentration of MEA in the fluid.

Abstract: Devices and methods for detecting chemicals are disclosed. A device configured for use in a wellbore includes a sensor including a quantum tunneling composite (QTC) material configured to exhibit a change in electrical resistance responsive to the sensor contacting a target chemical. The sensor includes electrical resistance measuring circuitry operably coupled to the QTC material and configured to measure the electrical resistance of the QTC material and output a sensor signal indicating the electrical resistance. A method comprises deploying the sensor into the wellbore, measuring the electrical resistance of the QTC material, and determining the presence of the target chemical responsive to detecting changes in the electrical resistance of the QTC material. Another method includes selecting at least one of the QTC material and an active material to interact with a target wellbore chemical to change the electrical resistance of the QTC material.

Abstract: A method of installing a downhole device comprises introducing a downhole device into a wellbore, the downhole device comprising a substrate and a shape memory polymer in a deformed state disposed on the substrate; combining a modified activation material in the form of a powder, a hydrogel, an xerogel, or a combination comprising at least one of the foregoing with a carrier to provide an activation fluid; introducing the activation fluid into the wellbore; releasing an activation agent in a liquid form from the modified activation material; and contacting the shape memory polymer in the deformed state with the released activation agent in an amount effective to deploy the shape memory polymer.

Abstract: Nanoparticles for use in the treatment of a well have a magnetic core of iron, nickel or cobalt or an alloy thereof; a carbon shell encapsulating the magnetic core; at least one organic functional group on the surface of the carbon shell through covalent bonding; and a coating of amorphous carbon nitride encapsulating the functionalized carbon shell. The nanoparticles may be used to identify fluids produced from the reservoir, identify the zone within the reservoir from which recovered fluid is produced, in water flooding to determine water breakthrough in the production well and to identify those injection wells from which breakthrough water originates.