Abstract: According to one embodiment, a sound absorbing urethane foam is provided. In the sound absorbing urethane foam, a normal incidence sound absorbing coefficient at a time when a diameter is 29 mm and a thickness is 10 mm is 40% or more in an entire range of frequencies of 1000 Hz to 3150 Hz.

Abstract: A pressure transducer comprises a housing including a body section and at least one end cap at one end of the body section, which are made of piezoelectric crystal, and a piezoelectric resonator in the housing. The body section and the end cap are bonded by an atomic diffusion bonding method.

Abstract: A pressure transducer comprises a housing including a body section and at least one end cap at one end of the body section, which are made of piezoelectric crystal, and a piezoelectric resonator in the housing. The body section and the end cap are bonded by an atomic diffusion bonding method.

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 improved manufacturing process for resonator-based pressure transducers is described. The process is a batch process in which several resonators are shaped simultaneously, using an etching process such as plasma etching. The end pieces are also shaped, if required, for several transducers. The end pieces and resonators are sandwiched together prior to separating the individual transducer units. The individual transducer units are then separated using a cutting process. The described process can be used to manufacture pressure transducers having a substantially smaller size, for example 5-6 mm outer dimensions and 2-3 mm resonators. The outer shape of the transducers can be a non-circular cylindrical shape such as that of a right square prism or an octagonal prism.

Abstract: Vibrating wire viscometers are disclosed. An example vibrating wire viscometer includes first and second electrically conductive tubes, where the first tube is at least partially inserted into the second tube, and where the first and second tubes are coupled via an electrically insulating bonding agent. The example viscometer further includes first and second electrically conductive pins inserted into respective ones of the first and second tubes, and an electrically conductive wire fastened to the first and second pins to vibrate in a downhole fluid to determine a viscosity of the downhole fluid.

Abstract: A pressure transducer for high-pressure measurements comprising a housing and a piezoelectric resonator located in the housing, wherein the resonator comprises double rotation cut piezoelectric material configured or designed for vibrating in the fundamental tone of dual modes of the fast and slow thickness-shear vibrations.

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: Vibrating wire viscometers are disclosed. An example apparatus to determine the viscosity of a downhole fluid is described, the apparatus including a wire to be immersed in a downhole fluid, to vibrate when an alternating current is applied to the wire within a magnetic field, and to generate an electromotive force when vibrating within the magnetic field, the wire comprising a first resistance. The apparatus further includes a nulling circuit coupled to the wire, wherein the nulling circuit comprises a second resistance that is selectable to be substantially equal to the first resistance, and an analyzer coupled to the wire and the nulling circuit to determine the first resistance, the second resistance, and a viscosity of the downhole fluid based on the first and second resistances, at least one characteristic of the wire, and the electromotive force.

Abstract: Methods and related systems are described for a sealed housing for downhole transducers. The housing system includes a housing body and a transducer positioned within the housing body, and one or more flexible members sealably mounted on the housing body. The flexible members each have one or more undulations which facilitate movement of the flexible member in directions primarily perpendicular to the surface of the flexible member. The dimensions of the one or more undulations are designed so as to optimize the ability of the movements of the member thereby accommodating volume changes in the sealed housing. A substantial amount of compensating material can also be positioned within the housing body. The compensating material has a coefficient of thermal expansion substantially less than that of the housing material.

Abstract: An improved manufacturing process for resonator-based pressure transducers is described. The process is a batch process in which several resonators are shaped simultaneously, using an etching process such as plasma etching. The end pieces are also shaped, if required, for several transducers. The end pieces and resonators are sandwiched together prior to separating the individual transducer units. The individual transducer units are then separated using a cutting process. The described process can be used to manufacture pressure transducers having a substantially smaller size, for example 5-6 mm outer dimensions and 2-3 mm resonators. The outer shape of the transducers can be a non-circular cylindrical shape such as that of a right square prism or an octagonal prism.

Abstract: Vibrating wire viscometers are disclosed. An example apparatus to determine the viscosity of a downhole fluid is described, the apparatus including a wire to be immersed in a downhole fluid, to vibrate when an alternating current is applied to the wire within a magnetic field, and to generate an electromotive force when vibrating within the magnetic field, the wire comprising a first resistance. The apparatus further includes a nulling circuit coupled to the wire, wherein the nulling circuit comprises a second resistance that is selectable to be substantially equal to the first resistance, and an analyzer coupled to the wire and the nulling circuit to determine the first resistance, the second resistance, and a viscosity of the downhole fluid based on the first and second resistances, at least one characteristic of the wire, and the electromotive force.

Abstract: Vibrating wire viscometers are disclosed. An example vibrating wire viscometer includes first and second electrically conductive tubes, where the first tube is at least partially inserted into the second tube, and where the first and second tubes are coupled via an electrically insulating bonding agent. The example viscometer further includes first and second electrically conductive pins inserted into respective ones of the first and second tubes, and an electrically conductive wire fastened to the first and second pins to vibrate in a downhole fluid to determine a viscosity of the downhole fluid.

Abstract: Methods and related systems are described for a sealed housing for downhole transducers. The housing system includes a housing body and a transducer positioned within the housing body, and one or more flexible members sealably mounted on the housing body. The flexible members each have one or more undulations which facilitate movement of the flexible member in directions primarily perpendicular to the surface of the flexible member. The dimensions of the one or more undulations are designed so as to optimize the ability of the movements of the member thereby accommodating volume changes in the sealed housing. A substantial amount of compensating material can also be positioned within the housing body. The compensating material has a coefficient of thermal expansion substantially less than that of the housing material.

Abstract: A resonator clock suitable for use in downhole conditions is described. The resonator clock includes a resonator portion of piezoelectric material; two electrodes in electrical communication with the resonator portion such that the resonator portion resonates when voltage is applied between the two electrodes; and four supports to support the resonator portion. The supports are dimensioned and positioned to support the resonator portion under shock and vibration encountered in downhole use. The supports and the resonator portion are formed from the same continuous piece of piezoelectric material.

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: An electrochemical sensor for measuring contents of a fluid or gas at high pressure and/or high temperature, for use, for example, in a wellbore for hydrocarbon applications, is provided. The sensor includes: a bulkhead-like electrode assembly including a cylindrical housing and a cylindrical electrode structure. The cylindrical electrode structure includes a cylindrical conductive pin extending from a high pressure region to a low pressure region and an electrode connected to one end of the pin at the high pressure region and having an electrode surface for exposure to a flow path of the fluid or gas in the high pressure region. At least a part of the surface of the pin is protected from direct contact with the fluid or the gas by an insulating coating impermeable to the fluid or gas. The pin may include an alternating pattern of protruding and receded portions.

Abstract: An electrochemical sensor for measuring contents of a fluid or gas at high pressure and/or high temperature, for use, for example, in a wellbore for hydrocarbon applications, is provided. The sensor includes: a bulkhead-like electrode assembly including a cylindrical housing and a cylindrical electrode structure. The cylindrical electrode structure includes a cylindrical conductive pin extending from a high pressure region to a low pressure region and an electrode connected to one end of the pin at the high pressure region and having an electrode surface for exposure to a flow path of the fluid or gas in the high pressure region. At least a part of the surface of the pin is protected from direct contact with the fluid or the gas by an insulating coating impermeable to the fluid or gas. The pin may include an alternating pattern of protruding and receded portions.

Abstract: A pressure transducer for high-pressure measurements comprising a housing and a piezoelectric resonator located in the housing, wherein the resonator comprises double rotation cut piezoelectric material configured or designed for vibrating in the fundamental tone of dual modes of the fast and slow thickness-shear vibrations.

Abstract: Techniques for reduced contamination formation evaluation are provided. The techniques relate to drawing fluid into a downhole tool positionable in a wellbore penetrating a subterranean formation having a virgin fluid and a contaminated fluid therein. Fluid is drawn into at least two inlets for receiving the fluids from the formation. At least one evaluation flowline is fluidly connected to at least one of the inlets for passage of the virgin fluid into the downhole tool. At least one cleanup flowline is fluidly connected to the inlets for passage of the contaminated fluid into the downhole tool. At least one fluid circuit is fluidly connected to the evaluation flowline and/or cleanup flowlines for selectively drawing fluid therein. At least one fluid connector is provided for selectively establishing a fluid connection between the flowlines. At least one sensor is provided for measuring downhole parameters in one of the flowlines.