Abstract: A downhole sensor includes a sensor housing with one or more of a pressure sensor or a temperature sensor. A cable segment having a conductor is coupled to the sensor housing. A spacer or retention element is coupled to or secured to at least a portion of the conductor at a location proximate an interface between the cable segment and the sensor housing. Downhole sensor arrays include such sensor housings. Methods relate to forming such sensor arrays.

Abstract: Downhole distributed pressure sensor arrays include sensor housings each comprising at least one pressure sensor in a pressure housing. Downhole pressure sensors include a housing, at least one pressure sensor in a pressure housing portion of the housing, and at least one isolation element positioned at an outer wall of the housing.

Abstract: A cylindrical quartz crystal transducer that exhibits a low probability of twinning, and uses a combination of resonator signal inputs at the B-mode and C-mode frequencies to calculate resonator temperature. Crystallographic orientations are disclosed where combinations of B-mode and C-mode resonant frequencies exist that are sufficiently independent of pressure to enable accurate calculation of temperature under transient conditions. Such a transducer is usable at higher pressures and temperatures than conventional quartz pressure transducers. Furthermore, because the structure allows a choice of crystallographic orientation, other characteristics of the transducer, such as increased pressure sensitivity and activity dip-free operation, may be optimized by varying crystallographic orientation.

Abstract: Transducer assemblies may include a sensor and a housing including a pass-through portion comprising at least one aperture in a portion of the housing extending along a longitudinal axis of the housing and the sensor. Methods of forming transducer assemblies may include welding a first housing section of the transducer assembly to a second housing portion of the transducer assembly and forming at least one aperture in the first housing section extending along a longitudinal axis of the transducer assembly, along a chamber for holding a sensor, and through the weld.

Abstract: A method of forming a microelectronic device structure comprises coiling a portion of a wire up and around at least one sidewall of a structure protruding from a substrate. At least one interface between an upper region of the structure and an upper region of the coiled portion of the wire is welded to form a fused region between the structure and the wire.

Abstract: Downhole distributed pressure sensor arrays include sensor housings each comprising at least one pressure sensor in a pressure housing. Downhole pressure sensors include a housing, at least one pressure sensor in a pressure housing portion of the housing, and at least one isolation element positioned at an outer wall of the housing.

Abstract: A method of forming a conditioned isolation element for a sensor assembly comprises subjecting a preformed isolation element structure to at least one thermal annealing process to form a conditioned isolation element structure substantially less susceptible to at least one of hydrogen permeation, hydrogen-based embrittlement, and hydrogen-based stress-cracking. Conditioned isolation elements and sensor assemblies are also described.

Abstract: Arrays of resonator sensors include an active wafer array comprising a plurality of active wafers, a first end cap array coupled to a first side of the active wafer array, and a second end cap array coupled to a second side of the active wafer array. Thickness shear mode resonator sensors may include an active wafer coupled to a first end cap and a second end cap. Methods of forming a plurality of resonator sensors include forming a plurality of active wafer locations and separating the active wafer locations to form a plurality of discrete resonator sensors. Thickness shear mode resonator sensors may be produced by such methods.

Abstract: A downhole sensor array includes sensor housings, and each sensor housing contains one or more of a pressure sensor and a temperature sensor. Cable segments connect the sensor housings. A weld joint bonds a sensor housing to a jacket of a cable segment, and a conductor of the cable segment and the jacket of the cable segment may be separated by a void proximate the weld joint. Methods relate to forming such sensor arrays.

Abstract: Transducer assemblies may include a sensor and a housing including a pass-through portion comprising at least one aperture in a portion of the housing extending along a longitudinal axis of the housing and the sensor. Methods of forming transducer assemblies may include welding a first housing section of the transducer assembly to a second housing portion of the transducer assembly and forming at least one aperture in the first housing section extending along a longitudinal axis of the transducer assembly, along a chamber for holding a sensor, and through the weld.

Abstract: A method of forming a microelectronic device structure comprises coiling a portion of a wire up and around at least one sidewall of a structure protruding from a substrate. At least one interface between an upper region of the structure and an upper region of the coiled portion of the wire is welded to form a fused region between the structure and the wire.

Abstract: A cylindrical quartz crystal transducer that exhibits a low probability of twinning, and uses a combination of resonator signal inputs at the B-mode and C-mode frequencies to calculate resonator temperature. Crystallographic orientations are disclosed where combinations of B-mode and C-mode resonant frequencies exist that are sufficiently independent of pressure to enable accurate calculation of temperature under transient conditions. Such a transducer is usable at higher pressures and temperatures than conventional quartz pressure transducers. Furthermore, because the structure allows a choice of crystallographic orientation, other characteristics of the transducer, such as increased pressure sensitivity and activity dip-free operation, may be optimized by varying crystallographic orientation.

Abstract: Isolation elements comprise a housing comprising a longitudinal bore formed therein and at least one recess formed in at least one longitudinally extending side of the housing. The at least one recess is in communication with the longitudinal bore. At least one diaphragm is attached proximate a periphery thereof to the housing and seals the at least one recess at the at least one longitudinally extending side of the housing. Sensor assemblies may include an isolation element including a housing and a diaphragm coupled thereto. Methods of forming an isolation element for use with a sensor comprise forming a longitudinal bore in a housing; forming at least one recess in at least one longitudinally extending side of the housing; coupling at least one diaphragm to the housing; and positioning the at least one diaphragm such that a primary direction of displacement of the at least one diaphragm extends into the at least one recess.

Abstract: Isolation elements comprise a housing comprising a longitudinal bore formed therein and at least one recess formed in at least one longitudinally extending side of the housing. The at least one recess is in communication with the longitudinal bore. At least one diaphragm is attached proximate a periphery thereof to the housing and seals the at least one recess at the at least one longitudinally extending side of the housing. Sensor assemblies may include an isolation element including a housing and a diaphragm coupled thereto. Methods of forming an isolation element for use with a sensor comprise forming a longitudinal bore in a housing; forming at least one recess in at least one longitudinally extending side of the housing; coupling at least one diaphragm to the housing; and positioning the at least one diaphragm such that a primary direction of displacement of the at least one diaphragm extends into the at least one recess.

Abstract: A pressure sensor having enhanced sensitivity without loss of accuracy over a broad pressure range. The sensor includes a resonator element sandwiched between two hollow end caps to form a sealed assembly. The sidewall thickness of the end caps abutting the resonator element is greater than the sidewall thickness at an area longitudinally spaced from the resonator, and the two dimensions may be selected to enhance sensitivity while maintaining accurate sensor performance. End cap endwalls of non-uniform thickness are employed with the thinnest endwall portion at the center and the thickest at the lateral periphery of the endwall. The rate of increase of end wall thickness toward the periphery may be modified to control the upper end of the pressure range in which the sensor is operable.

Abstract: A pressure transducer assembly for measuring fluid pressure. The transducer assembly includes a thickness-shear mode resonator pressure sensor and a thickness-shear mode resonator temperature sensor for temperature compensation of the pressure sensor. Both sensors are exposed to the pressurized fluid, and possess similar thermal time constants. The temperature sensor possesses a pressure sensitivity less than that of the pressure sensor, and a temperature sensitivity greater than that of the pressure sensor. The pressure and temperature sensors may be of similar size and configuration, and may be fabricated from the same material, such as quartz.

Abstract: A transducer sensing element isolation assembly including a pressure housing having a chamber in which the sensing element is disposed, which sensing element communicates with the interior of a bellows through a sealing element disposed between the pressure housing and a base on which the bellows is secured. The chamber, bellows interior and sealing element are filled with a dead volume of low compressibility, low thermal expansion isolation fluid. The bellows is contained in a replaceable bellows capsule which is threaded into a bellows capsule cavity into which the chamber communicates, and the sealing element is maintained in place by the capsule being made up into the cavity.

Abstract: A pressure transducer including a first pressure crystal, a second temperature crystal, a third reference crystal and associated electronics. All three crystals resonate in the thickness-shear mode.

Abstract: A differential mixer oscillator employing two transistors in a differential pair as the sustaining amplifier for a quartz crystal resonator at some first high frequency. The bias current of the differential pair is modulated at a second high frequency derived from some second frequency generating source, typically a second quartz crystal resonator, and the product terms are available at the collectors of the two transistors for selective filtering. The differential mixer oscillator may be employed in multiples, and with a variety of current sources, such as a Colpitts oscillator circuit.