Pressure measurements are vital for the development and completion of oil and gas wells for hydrocarbon production. High precision pressure measurements provide accurate estimates of the reservoir ...pressure, permeability, and gas/oil/ water interfaces in reservoirs that help in an optimal completion of wells for oil and gas production. This is based on identifying small differences in hydrostatic gradients caused by differences in mass densities of the gas, oil, and water. This differentiation can be accomplished by high resolution pressure measurements on the order of a few mpsi. Deeper oil and gas wells require pressure sensors that can operate up to 210 MPa (30 kpsi) and 210 °C or more. A dual-mode thickness-shear quartz pressure sensor has been commercialized to meet these high pressure and high temperature requirements for the deep drilling projects. This pressure sensor uses a doubly-rotated Stress-compensated for the B-mode, and temperature compensated for the C-mode (SBTC)-cut disc resonator sandwiched between two matching end caps. Hydrostatic pressure applied on the outside of the cylindrical probe transmits in-plane, compressive stresses to the sensing resonator and is a key feature of this design for high pressure applications. Optimal design of a bi-convex SBTC-cut resonator operating in the fundamental Band C-modes of vibration has led to the resonator having a Q*f product of about 9.18e11 for the B-mode and 5.02e12 for the C-mode. The metrological performance of this dual-mode thicknessshear over the target pressure and temperature ranges shows a calibration accuracy to be within 0.014 MPa (2 psi); a pressure resolution of about 20 Pa (0.003 psi), and stability of 0.003 MPa/week (0.5 psi/week).
Miniaturized, high-throughput, cost-effective sensing devices are needed to advance lab-on-a-chip technologies for healthcare, security, environmental monitoring, food safety, and research ...applications. Quartz crystal microbalance with dissipation (QCMD) is a promising technology for the design of such sensing devices, but its applications have been limited, until now, by low throughput and significant costs. In this work, we present the design and characterization of 24-element monolithic QCMD arrays for high-throughput and low-volume sensing applications in liquid. Physical properties such as geometry and roughness, and electrical properties such as resonance frequency, quality factor, spurious mode suppression, and interactions between array elements (crosstalk), are investigated in detail. In particular, we show that the scattering parameter, S 21 , commonly measured experimentally to investigate crosstalk, contains contributions from the parasitic grounding effects associated with the acquisition circuitry. Finite element method simulations do not take grounding effects into account explicitly. However, these effects can be effectively modelled with appropriate equivalent circuit models, providing clear physical interpretation of the different contributions. We show that our array design avoids unwanted interactions between elements and discuss in detail aspects of measuring these interactions that are often-overlooked.
Mindlin's two-dimensional theory has been derived and applied to research on quartz resonators for a long time. However, most works have focused on vibrations varying only in two directions, ...including thickness direction, while the effect of other directions like the length or width direction is normally neglected. Besides, researchers often model quartz resonators as fully electroded plates because of the resulting simplicity. Since a real device is finite in all directions and is only centrally electroded, results obtained in such works cannot offer quantitative information on vibrations with enough accuracy. In this paper, a theoretical analysis of a rectangular trapped-energy resonator of AT-cut quartz is studied using the Ritz method, associated with the variational formulation of Mindlin's first-order equations. Frequency spectra and mode shapes of a real-scaled trapped-energy resonator, which is finite in all directions, are obtained with the consideration of mode couplings among thickness-shear mode, thickness-twist mode, and flexural mode. Results show the existence of an energy-trapping and coupling phenomenon and are helpful for thorough and accurate understanding of quartz resonator vibrations. Detailed discussions on the effects of structural parameters on mode couplings and energy trapping are provided, and the results can helpfully guide the selection of aspect ratio, length/thickness ratio, and electrode inertia in device design.
The results of action of illumination on the piezoelectric characteristics of quartz resonators in the form of a tuning fork subjected to prior training with increased friction of the outside ambient ...are presented. It is found out that the piezoelectric characteristics of such resonators considerably change depending on the intensity and spectrum of illumination. A suggestion is made that the discovered change in the characteristics of the resonators is due to dislocations formed in the resonator during the training with increased friction of the outside ambient and is a display of the well-known photoplastic effect and its quenching.
This work shows the design, development and measurements of an innovative pressure sensor for high pressure and high temperature environments for offshore oil and gas exploration. The proposed sensor ...is produced with a simple microfabrication process, which enables large-scale manufacturing, reducing production costs. The advantage of low cost production using these sensors is the ability to design distributed pressure sensors systems at affordable prices to monitor smart wells in oil and gas production. The proposed sensor consists of a two-port SAW device in contrast to the common BAW pressure sensors typically used in the oil and gas industry. A test capsule was designed to measure the device under pressure and the sensitivity obtained by the measurements was found to be 14.8 Hz/psi. The operation range was 0-15,000 psi and the device must operate on temperatures up to 150 degreesC. Resolution was determined to be 1% of full scale. A capsule to package the sensor and circuits was designed and manufactured in 316L Stainless Steel. Results are very promising and expand the application of different kinds of sensors in the oil and gas industry.
This work demonstrates a gas flow rate sensor based on the curvature change of a micro quartz resonator (MQR). We explored the relationship between the resonant frequency shift and gas flow rate ...theoretically and experimentally. The sensing performance was evaluated by exposing the device to nitrogen gas at different flow rates. Experimental results indicate that the response time is less than 2 s with a sensitivity of 0.16 Hz/(mL·min −l ) in the gas flow ranging from 100 to 800 mL/min. Compared to the conventional gas sensors, our method has many advantages including low temperature drift, rapid response time, and great reproducibility, and provides a multifunctional sensing platform to measure the concentration and flow rate successfully. To the best of our knowledge, this is the first paper about gas flow rate sensing using the mechanical bending effect of an MQR.
Static and dynamic mechanical deflections were eLectrically induced in cantilevered, multiwalled carbon nanotubes in a transmission electron microscope. The nanotubes were resonantly excited at the ...fundamental frequency and higher harmonics as revealed by their deflected contours, which correspond closely to those determined for cantilevered elastic beams. The elastic bending modulus as a function of diameter was found to decrease sharply (from about I to 0.1 terapascals) with increasing diameter (from 8 to 40 nanometers), which indicates a crossover from a uniform elastic mode to an elastic mode that involves wavelike distortions in the nanotube. The quality factors of the resonances are on the order of 500. The methods developed here have been applied to a nanobalance for nanoscopic particles and also to a Kelvin probe based on nanotubes.
We report the fabrication and performance of a micromachined
Y-cut quartz resonator based thermal infrared detector array. 1
mm diameter and 18
μm thick (90
MHz) inverted mesa configuration quartz ...resonator arrays with excellent resonance characteristics have been fabricated by RIE etching of quartz. Temperature sensitivity of 7.2
kHz/K was experimentally measured. Infrared calibration tests on the resonator array even without the use of infrared absorbers gave a responsivity of 14.3
MHz/W and an NEP of 326
nW. In this first report on the performance of the
Y-cut quartz resonator infrared thermal detector array, the response time measurements were found to be limited by the slow measurement time of the impedance scans and the undesired heating of the quartz substrate. Most importantly, this initial work demonstrates the possibility of realizing infrared detector arrays for room temperature thermal imaging applications that can rival current state of the art in the field.
•We describe recent results in designing liquid helium BAW oscillators.•Optimal choice of electronic components is discussed.•Observed unique features of the cryogenic oscillators require ...modifications to the Leeson effect.•Main limitations in frequency stability are due to temperature fluctuations.
This work presents some recent results in the field of liquid helium bulk acoustic wave oscillators. The discussion covers the whole development procedure starting from component selection and characterisation and concluding with actual phase noise measurements. The associated problems and limitations are discussed. The unique features of obtained phase noise power spectral densities are explained with a proposed extension of the Leeson effect.
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