A method for determining a pressure profile in a subterranean formation is described. The method includes drilling a wellbore in the subterranean formation; lowering a logging tool into the wellbore to measure resistivity values as a function of depth along the wellbore; identifying a plurality of porous zones from the wellbore based on petrophysical logs; converting the measured resistivity values to an amount of total dissolved solids for each of the plurality of identified porous zones; converting the amount of total dissolved solids to a pore fluid density; calculating a pressure based on a sum of the pore fluid densities derived along a length of the well; and generating a depth-based pressure profile.

A piezoelectric sensor includes a substrate, a meta-membrane adhered to the substrate, and a piezoelectric element adhered to the meta-membrane. The substrate includes a support frame which laterally surrounds and partly defines a recess and a cover film which overlies and partly defines the recess. The support frame supports the cover film along an entire periphery of the cover film. The meta-membrane is adhered to the cover film of the substrate. In accordance with one embodiment, the meta-membrane has an auxetic bi-axial kirigami honeycomb structure. In accordance with another embodiment, the meta-membrane has an auxetic hexagonal honeycomb structure. The meta-membrane is adhered to the substrate and to the piezoelectric element using elastic glue. In one proposed implementation, the substrate and meta-membrane are made of polycarbonate and the piezoelectric element comprises a piezoelectric substrate made of polyvinylidene fluoride.

The invention relates to a measurement device 1 comprising a rotatable magnetic object 4 which can oscillate with a resonant frequency if excited by an external magnetic torque. The measurement device 1 is adapted such that the resonant frequency depends on the temperature or on another physical or chemical quantity like pressure, in order to allow for a wireless temperature measurement or measurement of the other physical or chemical quantity via an external magnetic field providing the external magnetic torque. This measurement device can be relatively small, can be read-out over a relatively larger distance and allows for a very accurate measurement.

A resonant pressure sensor with improved linearity includes a substrate including a substrate-fixed portion fixed to a housing-fixed portion and a substrate-separated portion separated from the housing-fixed portion in a first direction; a first resonator disposed in the substrate-separated portion to detect a change of a resonance frequency based on a strain caused by static pressure applied by a pressure-receiving fluid interposed in a gap between the housing-fixed portion and the substrate; a first electrode extending along a second direction to output an excitation signal to the first resonator; a second electrode that extends along the second direction and from which the first resonator outputs a signal having the resonance frequency; and a processor that measures the static pressure based on the detected change.

A sensor system that combines the sensing application of surface acoustic wave (SAW) sensor and sensor signal transfer though the enclosure wall via acoustic means. The sensor system includes SAW sensor placed inside the enclosure and at least one pair of bulk acoustic wave (BAW) transducers, one mounted inside and second outside the enclosure wall, allowing the interrogation of SAW sensor from outside the enclosure. The external BAW transducer converts interrogation electrical pulse into acoustic pulse which travels though the enclosure wall to the internal BAW transducer. The internal BAW transducer converts the interrogation electrical pulse to electrical pulse and transfers it to SAW sensor. The response of the SAW transducer containing series of electric pulses is converted to the series of acoustic pulses by internal BAW transducer which propagates though enclosure wall. The external BAW transducer converts the series of acoustic pulses into series of electrical pulses and is received by the interrogation circuit for processing.

We present a microelectromechanical system (MEMS) graphene-based pressure sensor realized by transferring a large area, few-layered graphene on a suspended silicon nitride thin membrane perforated by a periodic array of micro-through-holes. Each through-hole is covered by a circular drum-like graphene layer, namely a graphene “microdrum”. The uniqueness of the sensor design is the fact that introducing the through-hole arrays into the supporting nitride membrane allows generating an increased strain in the graphene membrane over the through-hole array by local deformations of the holes under an applied differential pressure. Further reasons contributing to the increased strain in the devised sensitive membrane include larger deflection of the membrane than that of its imperforated counterpart membrane, and direct bulging of the graphene microdrum under an applied pressure. Electromechanical measurements show a gauge factor of 4.4 for the graphene membrane and a sensitivity of 2.8×10-5 mbar-1 for the pressure sensor specific example described, with a good linearity over a wide pressure range. The present sensor outperforms most existing MEMS-based small footprint pressure sensors using graphene, silicon, and carbon nanotubes as sensitive materials, due to the high sensitivity.

A pressure sensing device for sensing pressure. The pressure sensing device includes a sealed chamber, a second flexible diaphragm, and a protector member. The sealed chamber includes an upper portion comprising a first flexible diaphragm and a lower portion. The protector member includes a bottom surface with a fist concave shape, a top surface with a second concave shape, and a longitudinal hole between a lower cavity and an upper cavity. The lower cavity is between the first flexible diaphragm and a bottom surface of the protector member. The upper cavity is between the second flexible diaphragm and an upper surface of the protector member.

To provide a pressure sensor element and a pressure sensor that have stable pressure sensitivity without the need for improving the accuracy of alignment between a diaphragm and a holding member, a pressure sensor element includes a thin plate diaphragm, a holding member that holds the diaphragm, and one or more strain resistance gauges that are provided on a first surface of the diaphragm and which change in resistance values according to deformation of the diaphragm, in which the holding member has recesses that, formed on an annular first end surface facing the first surface of the diaphragm, cut out parts of an inner circumference of the first end surface, and the strain resistance gauges are disposed near the regions corresponding to the recesses on the first surface of the diaphragm.

A no-gel sensor package is disclosed. In one embodiment, the package includes a microelectromechanical system (MEMS) die having a first substrate, which in turn includes a first surface on which is formed a MEMS device. The package also includes a polymer ring with an inner wall extending between first and second oppositely facing surfaces. The first surface of the polymer ring is bonded to the first surface of the first substrate to define a first cavity in which the MEMS device is contained. A molded compound body having a second cavity that is concentric with the first cavity, enables fluid communication between the MEMS device and an environment external to the package.

A pressure sensor includes a first pressure sensing portion and a second pressure sensing portion, each including a first rigid electrode, a second rigid electrode, and a deflectable membrane structure, wherein the second rigid electrode is between the first rigid electrode and the deflectable membrane structure, and wherein the first rigid electrode, the second rigid electrode and the deflectable membrane structure are in a vertical configuration, and wherein the first and second rigid electrode of the first pressure sensing portion form a reference capacitor, and wherein the second rigid electrode and the deflectable membrane structure of the first pressure sensing portion form a sensing capacitor, and wherein the first and second rigid electrode of the second pressure sensing portion form a reference capacitor, and wherein the second rigid electrode and the deflectable membrane structure of the second pressure sensing portion form a sensing capacitor.