Abstract: A piezoelectric transducer is mounted in a housing. An impedance matching layer is provided between the piezoelectric transducer and the housing. The impedance matching layer includes high-permittivity regions that have a first permittivity, and low-permittivity regions that separate the high-permittivity regions and have a second permittivity. The second permittivity is lower than the first permittivity.

Abstract: Various embodiments include apparatus and methods of providing a piezoelectric element having a surface front surface to operate as an active surface of a transducer on which a number of separate electrodes are disposed such that the electrodes on the front surface provide an effectively flat surface to the transducer. Additional apparatus, systems, and methods are disclosed.

Abstract: A focused acoustic transducer suitable for use in a downhole environment is disclosed. At least some embodiments employ a disk of piezoelectric material with low planar coupling and low Poisson's ratio mounted on a backing material and sealed inside an enclosure. The piezoelectric material disk has a pattern of electrodes deposited on an otherwise smooth, ungrooved surface. Despite the lack of grooves, the material's low planar coupling and low Poisson's ratio enables the electrodes to operate in a phased relationship to provide and receive focused acoustic pulses. Moreover, the elimination of deep cuts offers a much lower cost of construction. The electrode material may be any conductive material, though silver and silver alloys are contemplated. The patterning of electrodes can occur during the deposition process (e.g., using a silk-screen or other printing technique) or afterwards (e.g., mechanically or chemically with an etch technique that uses a pre- or post-deposition photoresist layer).

Abstract: A piezoelectric transducer is mounted in a housing. An impedance matching layer is provided between the piezoelectric transducer and the housing. The impedance matching layer includes high-permittivity regions that have a first permittivity, and low-permittivity regions that separate the high-permittivity regions and have a second permittivity. The second permittivity is lower than the first permittivity.

Abstract: A piezoelectric element and a manufacturing method to reduce extraneous radial vibration modes is disclosed, in an example embodiment, four slots, arranged at 90 degrees, are made in one surface such that the slots do not reach the opposite surface.

Abstract: A device includes a piezoelectric transducer. The transducer has N independent transducer regions. N is an integer. Each of the N independent transducer regions has a thickness. Each of the N independent transducer regions has an acoustic impedance AIT. Each of the N independent transducer regions is independently excitable to oscillate in the thickness mode when electrically excited by a potential difference applied across the thickness. The device further includes a first impedance matching layer having an acoustic impedance AI1 and AIT and a borehole fluid acoustic impedance AIBF. The first impedance matching layer is situated such that an acoustic signal emitted by the piezoelectric transducer will pass through the second impedance matching layer. The device further includes a second impedance matching layer having an acoustic impedance AI2 between AI1 and AIBF.

Abstract: Various embodiments include apparatus and methods of providing a sensor, in a transducer subassembly, having a backing (1) coupled to a housing (7) without bonding the sensor to the housing such that the sensor is effectively mechanically decoupled from the housing except for longitudinal waves traveling through the front face of the transducer subassembly. Additional apparatus, systems, and methods are disclosed.

Abstract: A device includes a piezoelectric transducer. The transducer has N independent transducer regions. N is an integer. Each of the N independent transducer regions has a thickness. Each of the N independent transducer regions has an acoustic impedance AIT. Each of the N independent transducer regions is independently excitable to oscillate in the thickness mode when electrically excited by a potential difference applied across the thickness. The device further includes a first impedance matching layer having an acoustic impedance AI1 and AIT and a borehole fluid acoustic impedance AIBF. The first impedance matching layer is situated such that an acoustic signal emitted by the piezoelectric transducer will pass through the second impedance matching layer. The device further includes a second impedance matching layer having an acoustic impedance AI2 between AI1 and AIBF.

Abstract: A focused acoustic transducer suitable for use in a downhole environment is disclosed. At least some embodiments employ a disk of piezoelectric material with low planar coupling and low Poisson's ratio mounted on a backing material and sealed inside an enclosure. The piezoelectric material disk has a pattern of electrodes deposited on an otherwise smooth, ungrooved surface. Despite the lack of grooves, the material's low planar coupling and low Poisson's ratio enables the electrodes to operate in a phased relationship to provide and receive focused acoustic pulses. Moreover, the elimination of deep cuts offers a much lower cost of construction. The electrode material may be any conductive material, though silver and silver alloys are contemplated. The patterning of electrodes can occur during the deposition process (e.g., using a silk-screen or other printing technique) or afterwards (e.g., mechanically or chemically with an etch technique that uses a pre- or post-deposition photoresist layer).

Abstract: Various embodiments include apparatus and methods of providing a piezoelectric element having a surface front surface to operate as an active surface of a transducer on which a number of separate electrodes are disposed such that the electrodes on the front surface provide an effectively flat surface to the transducer. Additional apparatus, systems, and methods are disclosed.

Abstract: A piezoelectric element and a manufacturing method to reduce extraneous radial vibration modes is disclosed, in an example embodiment, four slots, arranged at 90 degrees, are made in one surface such that the slots do not reach the opposite surface.

Abstract: Various embodiments include apparatus and methods of providing a sensor, in a transducer subassembly, having a backing (1) coupled to a housing (7) without bonding the sensor to the housing such that the sensor is effectively mechanically decoupled from the housing except for longitudinal waves traveling through the front face of the transducer subassembly. Additional apparatus, systems, and methods are disclosed.

Abstract: A system for non-destructively measuring the strength of a cement slurry sample includes an elongate sample container for receiving a cement slurry sample. The elongate sample container has a mass mounted at its first end. A transducer mounted at a second end of the elongate sample container vibrates the elongate sample container and mass. The elongate sample container, mass and transducer have a known resonance. The system calculates the strength of a tested cement slurry within the elongate sample container as a function of variation in resonance of the elongate sample container, mass and transducer.

Abstract: An acoustic transducer system for use in the measurement of longitudinal sound velocity in a cement sample that is maintained at high temperature and pressure. The acoustic assembly is separate from the end plugs to optimize acoustic coupling between the individual elements of the assembly, to increase the amplitude and consistency of the acoustic signal and to provide an ability to replace the transducers as a separate assembly. The transducer includes an acoustic transmission line and utilizes a pressure isolation method to optimize the material and the manufacturing process to enhance the acoustic signal required for the measurement. The transducer assembly includes a high temperature piezoelectric ceramic and a load mass that improve the signal amplitude and provide the required electrical connections. The transducer improves the ability to measure the longitudinal wave velocity in a cement sample at elevated temperature and pressure for determining the sample's compressive strength.

Abstract: A system for non-destructively measuring the strength of a cement slurry sample includes an elongate sample container for receiving a cement slurry sample. The elongate sample container has a mass mounted at its first end. A transducer mounted at a second end of the elongate sample container vibrates the elongate sample container and mass. The elongate sample container, mass and transducer have a known resonance. The system calculates the strength of a tested cement slurry within the elongate sample container as a function of variation in resonance of the elongate sample container, mass and transducer.

Abstract: An acoustic transducer system for use in the measurement of longitudinal sound velocity in a cement sample that is maintained at high temperature and pressure. The acoustic assembly is separate from the end plugs to optimize acoustic coupling between the individual elements of the assembly, to increase the amplitude and consistency of the acoustic signal and to provide an ability to replace the transducers as a separate assembly. The transducer includes an acoustic transmission line and utilizes a pressure isolation method to optimize the material and the manufacturing process to enhance the acoustic signal required for the measurement. The transducer assembly includes a high temperature piezoelectric ceramic and a load mass that improve the signal amplitude and provide the required electrical connections. The transducer improves the ability to measure the longitudinal wave velocity in a cement sample at elevated temperature and pressure for determining the sample's compressive strength.

Abstract: An apparatus for determining dynamic mechanical properties of a cement sample. The apparatus includes an isolator located within a cavity defined by a body. The isolator has an attached end that engages the body proximate a narrow end of the cavity. A space between the body and isolator facilitates lateral movement the isolator. A transducer is located in an interior space defined by the isolator. The transducer has an attached end engaging a distal end of the isolator. A space between the isolator and transducer facilitates lateral movement of the transducer distal end. The transducer generates compressional waves and shear waves that travel into the sample. An ultrasonic receiver receives the waves. The waves are separated with filtering. Sample setting time may be determined from propagation time of shear waves through the sample. Compressive strength of the sample is determined by velocity of compressional waves as the sample sets.

Abstract: A method of estimating the compressive strength of a foam cement sample from a parametric measurement (base cement compressive strength) obtainable from conventional equipment, wherein standard laboratory measurements are used to establish the relationship between the base cement compressive strength, the volume percent entrained gas and the compressive strength of the subject foam cement.

Abstract: A dynamic fluid loss cell apparatus and method for measuring filter-cake build-up on a simulated core of the well-bore and for measuring the effectiveness of a spacer fluid to remove filter-cake. There is also provided, a dynamic fluid loss cell apparatus and method for measuring the dynamic fluid loss during the simulated build-up and removal of the filter-cake. The apparatus and method further provides for performing the measurements under various conditions including temperature and differential pressure.

Abstract: An apparatus and method for wettability measurements are provided. The apparatus includes a surface having a pair of electrodes separated by an insulator affixed thereto. The electrodes are operable for supporting an oil film, and the may be immersed in a surfactant solution. Circuitry for measuring the complex impedance between the electrodes is coupled to the electrodes. The capacitive part of the complex impedance provides a measure of the oil thickness as it is removed by the surfactant solution. A rotating member is provided for agitating the surfactant solution thereby modifying the effectiveness of the solution in removing the film.