Abstract: An electrochemical fluid sensor for a downhole production tool positionable in a wellbore penetrating a subterranean is provided. The wellbore has a downhole fluid therein. The electrochemical fluid sensor includes a sensor housing positionable in the downhole tool, a sensing solution positionable in the housing (the sensing solution including a mediator reactive to target chemicals), a gas permeable membrane to fluidly isolate the downhole fluid from the sensing solution (the gas permeable membrane permitting the passage of gas to the sensing solution), and a plurality of electrodes positioned about the housing a distance from the gas permeable membrane to measure reaction by the sensing solution whereby downhole parameters may be determined.

Abstract: The present invention, in one set of embodiments, provides methods and systems for integrating conducting diamond electrodes into a high power acoustic resonator. More specifically, but not by way of limitation, in certain embodiments of the present invention, diamond electrodes may be integrated into a high power acoustic resonator to provide a robust sensing device that may provide for acoustic cleaning of the electrodes and increasing the rate of mass transport to the diamond electrodes. The diamond electrodes may be used as working, reference or counter electrodes or a combination of two or more of such electrodes. In certain aspects, the high power acoustic resonator may include an acoustic horn for focusing acoustic energy and the diamond electrodes may be coupled with the acoustic horn.

Abstract: An electrochemical sensor of a downhole tool positionable in a wellbore penetrating a subterranean formation is provided. The downhole tool has a flowline to receive downhole fluid. The electrochemical sensor includes a bulkhead carried by the downhole tool, a membrane exposed to the downhole fluid in the flowline, and an electrochemical cell supported by the bulkhead about the membrane. The electrochemical cell includes a plurality of cell sensors, at least one cell electrode, and a sensing solution. The plurality cell sensors include an analyte sensor, a temperature sensor, and a pH sensor. The sensing solution is reactive to certain analytes in the downhole fluid to generate electrical signals measurable by the plurality of cell sensors whereby parameters of chemicals in the downhole fluid may be measured.

Abstract: An electrochemical sensor for the presence or concentration of an analyte has at least one electrode and at least one electrochemically active species able to undergo electrochemical reaction in response to electrical potential applied to the electrode, where the said reaction is modified by the presence of the analyte. This sensor has the novel characteristic that at least one said electrochemically active species is encapsulated within polymer particles. These particles are preferably formed from an amorphous polymer with a glass transition temperature above the temperature of the fluid to which the sensor is exposed. The encapsulating polymer protects the analyte species from degradation, but a small analyte such as a hydrogen or bisulfide ion can pass through the polymer and undergo reaction at the active species.

Abstract: A method of measuring pH of aqueous liquid with little or no buffer present uses an electrochemical pH sensor which comprises a plurality of electrodes with a redox active organic compound attached to an electrode and having at least one functional group convertible electrochemically between reduced and oxidized forms with transfer of at least one proton between the compound and surrounding aqueous phase, wherein the compound has at least one substituent group which promotes hydrogen bonding at a said functional group and thereby increases the reaction rate of proton transfer. The substituent group may form an internal hydrogen bond with a redox-convertible group or may enhance polarity to promote electrostatic interaction with water molecules and reduce activation energy. Such an electrochemical sensor may be used for pH measurement in computer controlled equipment for processing an aqueous liquid.

Abstract: An electrochemical fluid sensor for a downhole production tool positionable in a wellbore penetrating a subterranean is provided. The wellbore has a downhole fluid therein. The electrochemical fluid sensor includes a sensor housing positionable in the downhole tool, a sensing solution positionable in the housing (the sensing solution including a mediator reactive to target chemicals), a gas permeable membrane to fluidly isolate the downhole fluid from the sensing solution (the gas permeable membrane permitting the passage of gas to the sensing solution), and a plurality of electrodes positioned about the housing a distance from the gas permeable membrane to measure reaction by the sensing solution whereby downhole parameters may be determined.

Abstract: An electrochemical sensor of a downhole tool positionable in a wellbore penetrating a subterranean formation is provided. The downhole tool has a flowline to receive downhole fluid. The electrochemical sensor includes a bulkhead carried by the downhole tool, a membrane exposed to the downhole fluid in the flowline, and an electrochemical cell supported by the bulkhead about the membrane. The electrochemical cell includes a plurality of cell sensors, at least one cell electrode, and a sensing solution. The plurality cell sensors include an analyte sensor, a temperature sensor, and a pH sensor. The sensing solution is reactive to certain analytes in the downhole fluid to generate electrical signals measurable by the plurality of cell sensors whereby parameters of chemicals in the downhole fluid may be measured.

Abstract: A gas separation and detection tool for performing in situ analysis of borehole fluid is described. The tool comprises a sampling chamber for a downhole fluid. The sample chamber comprises a detector cell with an opening. The tool also comprises a gas separation module for taking a gas from the downhole fluid. The gas separation module comprises a membrane located in the opening, a support for holding the membrane, and a sealant applied between the housing and the membrane or support. Moreover, the tool comprises a gas detector for sensing the gas.

Abstract: An electrode for the determination of pH is made by depositing a phenolic compound on a conductive substrate, where the phenolic compound has a phenolic hydroxy group attached to a carbon atom on an aromatic ring and also has an oxygen atom connected through one other atom to an adjacent carbon atom of the aromatic ring such that this oxygen atom can form a hydrogen bond to the phenolic hydroxy group; and then electrochemically oxidising the immobilized phenolic compound in a one electron one proton oxidation so as to form a polymeric, water-insoluble, redox-active deposit on the conductive substrate. The electrode is useful for electrochemical determination of pH and is capable of measuring pH of an unbuffered aqueous liquid.

Abstract: The present invention, in one set of embodiments, provides methods and systems for integrating conducting diamond electrodes into a high power acoustic resonator. More specifically, but not by way of limitation, in certain embodiments of the present invention, diamond electrodes may be integrated into a high power acoustic resonator to provide a robust sensing device that may provide for acoustic cleaning of the electrodes and increasing the rate of mass transport to the diamond electrodes. The diamond electrodes may be used as working, reference or counter electrodes or a combination of two or more of such electrodes. In certain aspects, the high power acoustic resonator may include an acoustic horn for focusing acoustic energy and the diamond electrodes may be coupled with the acoustic horn.

Abstract: A method of measuring pH of aqueous liquid with little or no buffer present uses an electrochemical pH sensor which comprises a plurality of electrodes with a redox active organic compound attached to an electrode and having at least one functional group convertible electrochemically between reduced and oxidized forms with transfer of at least one proton between the compound and surrounding aqueous phase, wherein the compound has at least one substituent group which promotes hydrogen bonding at a said functional group and thereby increases the reaction rate of proton transfer. The substituent group may form an internal hydrogen bond with a redox-convertible group or may enhance polarity to promote electrostatic interaction with water molecules and reduce activation energy. Such an electrochemical sensor may be used for pH measurement in computer controlled equipment for processing an aqueous liquid.

Abstract: An electrochemical sensor for the presence or concentration of an analyte has at least one electrode and at least one electrochemically active species able to undergo electrochemical reaction in response to electrical potential applied to the electrode, where the said reaction is modified by the presence of the analyte. This sensor has the novel characteristic that at least one said electrochemically active species is encapsulated within polymer particles. These particles are preferably formed from an amorphous polymer with a glass transition temperature above the temperature of the fluid to which the sensor is exposed. The encapsulating polymer protects the analyte species from degradation, but a small analyte such as a hydrogen or bisulfide ion can pass through the polymer and undergo reaction at the active species.

Abstract: A gas separation and detection tool for performing in situ analysis of borehole fluid is described. The tool comprises a sampling chamber for a downhole fluid. The sample chamber comprises a detector cell with an opening. The tool also comprises a gas separation module for taking a gas from the downhole fluid. The gas separation module comprises a membrane located in the opening, a support for holding the membrane, and a sealant applied between the housing and the membrane or support. Moreover, the tool comprises a gas detector for sensing the gas.

Abstract: The present invention, in one set of embodiments, provides methods and systems for integrating conducting diamond electrodes into a high power acoustic resonator. More specifically, but not by way of limitation, in certain embodiments of the present invention, diamond electrodes may be integrated into a high power acoustic resonator to provide a robust sensing device that may provide for acoustic cleaning of the electrodes and increasing the rate of mass transport to the diamond electrodes. The diamond electrodes may be used as working, reference or counter electrodes or a combination of two or more of such electrodes. In certain aspects, the high power acoustic resonator may include an acoustic horn for focusing acoustic energy and the diamond electrodes may be coupled with the acoustic horn.

Abstract: The present invention, in one set of embodiments, provides methods and systems for integrating conducting diamond electrodes into a high power acoustic resonator. More specifically, but not by way of limitation, in certain embodiments of the present invention, diamond electrodes may be integrated into a high power acoustic resonator to provide a robust sensing device that may provide for acoustic cleaning of the electrodes and increasing the rate of mass transport to the diamond electrodes. The diamond electrodes may be used as working, reference or counter electrodes or a combination of two or more of such electrodes. In certain aspects, the high power acoustic resonator may include an acoustic horn for focusing acoustic energy and the diamond electrodes may be coupled with the acoustic horn.

Abstract: A gas separation and detection tool for performing in situ analysis of borehole fluid is described. A separation system such as a membrane is employed to separate one or more target gasses from the borehole fluid. The separated gas may be detected by reaction with another material or spectroscopy. When spectroscopy is employed, a test chamber defined by a housing is used to hold the gas undergoing test. Various techniques may be employed to protect the gas separation system from damage due to pressure differential. For example, a separation membrane may be integrated with layers that provide strength and rigidity. The integrated membrane separation may include one or more of a water impermeable layer, gas selective layer, inorganic base layer and metal support layer. The gas selective layer itself can also function as a water impermeable layer. The metal support layer enhances resistance to differential pressure. Alternatively, the chamber may be filled with a liquid or solid material.

Abstract: The present invention, in one set of embodiments, provides methods and systems for integrating conducting diamond electrodes into a high power acoustic resonator. More specifically, but not by way of limitation, in certain embodiments of the present invention, diamond electrodes may be integrated into a high power acoustic resonator to provide a robust sensing device that may provide for acoustic cleaning of the electrodes and increasing the rate of mass transport to the diamond electrodes. The diamond electrodes may be used as working, reference or counter electrodes or a combination of two or more of such electrodes. In certain aspects, the high power acoustic resonator may include an acoustic horn for focusing acoustic energy and the diamond electrodes may be coupled with the acoustic horn.