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: The present disclosure is directed at methods, apparatuses, and techniques for detecting an acoustic event along a channel. Different wavelengths of an optical signal are multiplexed along a fiber optic strand extending along the channel. The strand has groups of transducers located along its length, and all of the transducers in any one of the groups reflect a tuned wavelength when not under strain. The wavelength that the transducers reflect changes in response to strain. Optical signal processing equipment receives reflected optical signals from the groups of transducers, and determines, for each of the groups of transducers, differences between wavelengths of the optical signals reflected by the transducers of that group and the tuned wavelength for that group. The differences correspond to the loudness of the event measured by that group of transducers, which can then be graphically represented to a person for analysis.

Abstract: A device for employing sonic transmissions is utilized to determine fluid level in a well or a container. The device may be utilized while the well is operating. It is known that wells replenish fluid at different rates even in the same formation or well field. Increased well production at minimum pumping cost is achieved for a given well. The device generates a sonic event through the use of a compressed fluid that is obtained from within a well. A fluid level measurement system is obtained in a well in which gas is produced under vacuum.

Abstract: Provided is a measuring apparatus with AE sensors, which detects the same AE signals with respect to the same events that damage a geotechnical structure, regardless of ground conditions and formations in the geotechnical structure, thereby collecting reliable AE signals. Also, provided is(are) an installing method of the measuring apparatus with the AE sensor, and a set of the measuring apparatus with the AE sensor.

Abstract: A downhole tool includes a sensor having a sensitive component, a polymer that at least partially covers the sensitive component, and a hydrophobic material impregnated within the polymer and/or the sensitive component of the sensor. Methods of forming the downhole tool include covering a portion of the sensor with a polymer and impregnating a hydrophobic material within the polymer and/or the sensitive component of the sensor.

Abstract: Methods and related systems are described relating to a sealed acoustic transducer assembly for use in a wellbore is provided. A tool body is deployed in the wellbore, having a groove and a sealed acoustic transducer assembly removeably mounted therein. The transducer assembly includes an acoustic transducer element, and an elongated fluid filled sealed container housing the transducer element. The container includes flexible portions along the length of the container which allows for volume changes when exposed to changes in external pressure and/or temperature. Acoustic measurements downhole are made using the transducer element.

Abstract: There is provided a transducer assembly for monitoring within a borehole. The transducer assembly is operable to at least one of: (a) generate acoustic radiation when excited with one or more signals; and (b) generate one or more signals when acoustic radiation is received thereat; wherein the transducer assembly includes one or more piezo-electric elements for converting between acoustic radiation and corresponding signals. The assembly includes an interfacing member for acoustically interfacing between the one or more piezo-electric elements and an environment of the borehole for protecting the one or more piezo-electric elements from the environment. The assembly is adapted to at least one of generate acoustic radiation and sense acoustic radiation in a sideways or down-borehole direction.

Abstract: A wellbore instrument includes a housing configured to traverse a subsurface wellbore. A shock and vibration sensor disposed in the housing and is mounted on a carrier disposed in the housing. The carrier includes at least two, laterally movable elements each having an outer surface configured to contact an inner surface of the housing. The carrier includes an adjustable wedge disposed between the opposed elements. The wedge is arranged such that longitudinal movement thereof causes lateral separation of the laterally movable elements into frictional engagement with the inner surface of the housing.

Abstract: A downhole tool damage detection method includes transmitting ultrasonic energy through a downhole tool, receiving ultrasonic energy transmitting through the downhole tool, monitoring the received ultrasonic energy for changes over time and alerting that at least partial unthreading of a threaded connection in the downhole tool may exist in response to finding the changes.

Abstract: An expandable apparatus may comprise a tubular body, a valve piston and a push sleeve. The tubular body may comprise a fluid passageway extending therethrough, and the valve piston may be disposed within the tubular body, the valve piston configured to move axially downward within the tubular body responsive to a pressure of drilling fluid passing through a drilling fluid flow path and configured to selectively control a flow of fluid into an annular chamber. The push sleeve may be disposed within the tubular body and coupled to at least one expandable feature, the push sleeve configured to move axially responsive to the flow of fluid into the annular chamber extending the at least one expandable feature. Additionally, the expandable apparatus may be configured to generate a signal indicating the extension of the at least one expandable feature.

Abstract: In one aspect, the disclosure provides an apparatus for use downhole that includes at least one acoustic sensor. In one aspect, the acoustic sensor includes a chamber and an active element comprised of a quantum tunneling composite in the chamber. In another aspect, the acoustic sensor may further include a pair of conductive layers on a pair of sides of the active element. The chamber is filled with an electrically non-conductive fluid. The active element may be placed in the chamber in a manner that causes the active element to be responsive to acoustic waves along a selected direction or in a manner that enables the active element to be non-directional.

Abstract: A downhole tool includes circumferentially spaced and/or angled transducer elements. In one embodiment a standoff sensor has at least three piezoelectric transducer elements, at least a first element of which is configured to both transmit and receive ultrasonic energy. At least second and third of the elements are configured to receive ultrasonic energy transmitted by the first element in pitch catch mode. An electronic controller is configured to calculate a standoff distance from the ultrasonic waveforms received at the first, the second, and the third piezoelectric transducer elements. The controller may further be configured to estimate the eccentricity of a measurement tool in the borehole. Exemplary embodiments of the invention may improve borehole coverage and data quality and reliability in LWD caliper logging. In particular, the invention may advantageously reduce or even eliminate blind spots when logging eccentric bore holes.

Abstract: A sensor system for sensing a process variable of fluid at a first location including a variable resonator disposed at the first location having a resonant frequency which varies in response to the process variable of the fluid and responsively provides a resonant acoustic signal at the resonant frequency indicative of the process variable. An acoustic sensor disposed at a second location which is spaced apart from the variable resonator is configured to receive the resonant acoustic signal transmitted from the variable resonator. Measurement circuitry coupled to the acoustic sensor configured to provide a process variable output related to the process variable of the fluid in response to the received resonant acoustic signal.

Abstract: The invention relates to a downhole pressure- and vibration-measuring device integrated in a pipe section (1) as part of a production tubing (20). The sensor housing (2) of the measuring device with sensors has a two-part clamp (3) on the upper part of the sensor housing (2), from where an electrical multi- conductor cable connection (10) from at least four, preferably six, nipples in a tube (9) is clamped along the production tubing (20) with bushings through equipment installed in the wellhead to sensors with an electronics and control unit (12) above the wellhead. Evenly-spaced radially in an annular space (5) are a first set of strain gauges (7) attached to the outside wall of the production tubing (20) and a second set of strain gauges (8) attached on the inside of the external wall of the sensor housing (2). Strain gauges (7, 8) are connected by glass penetrators (4) of electrical conductors in cable tubes (9A) terminated in the tubing hanger (21) to an electronics unit (11) and a control unit (12).

Abstract: Provided is a measuring apparatus with AE sensors, which detects the same AE signals with respect to the same events that damage a geotechnical structure, regardless of ground conditions and formations in the geotechnical structure, thereby collecting reliable AE signals. Also, provided is(are) an installing method of the measuring apparatus with the AE sensor, and a set of the measuring apparatus with the AE sensor.

Abstract: The invention concerns an independent measuring and processing probe designed to be lowered in a tube for temporarily installation at the bottom of a hydrocarbon well. It includes removable anchoring resources (3, 4) capable of anchoring the probe to a casing at the bottom of the well, a set of sensors, at least one of which is a seismic sensor, recording resources, resources for processing the measurements provided by the sensors, and a central body (1) integrally reamed throughout the whole of its length by an opening (2) so as to allow free passage through the probe when it is in the anchored position. Such a probe can be used in particular to effect a reliable preliminary study on the well before installing a more complete observation system.

Abstract: A transducer for use with a downhole tool, where the transducer includes concentric piezoelectric elements coupled with a member that extends from the top surface of one element to the bottom surface of another element. The elements expand and contract to vibrate by applying electrical potential to the elements. The element having the member on its bottom surface expands and contracts with applied electrical potential and also is urged upward, by the coupling member, an amount equal to the vertical displacement of the element having the member on its top surface. Thus the element having the member on its bottom surface is vertically displaced by an amount substantially equal to the expansion of the elements.

Abstract: An apparatus comprises a tensioned sample tube that receives a fluid sample, the tensioned sample tube has a pre-determined tension applied thereto. A vibration source and a vibration detector are coupled to the tensioned sample tube. A method of estimating a property of a fluid comprises tensioning a sample tube to a predetermined tension. A sample of the fluid is received in the tensioned sample tube. The tensioned sample tube is vibrated. A resonant frequency of the tensioned sample tube is detected. The property of the fluid is estimated based on the detected resonant frequency of the tensioned sample tube.

Abstract: A sensor apparatus includes a first elongated housing to at least partially enclose a sensor device and a second elongated housing coupled longitudinally to the first elongated housing. The second elongated housing includes at least one radial port extending from an inner surface to an outer surface of the second elongated housing to allow a first material received through an opening of the second elongated housing to flow through the second elongated housing and out the radial port in the vicinity of the sensor apparatus.

Abstract: A wellbore instrument includes a housing configured to traverse a subsurface wellbore. A shock and vibration sensor disposed in the housing and is mounted on a carrier disposed in the housing. The carrier includes at least two, laterally movable elements each having an outer surface configured to contact an inner surface of the housing. The carrier includes an adjustable wedge disposed between the opposed elements. The wedge is arranged such that longitudinal movement thereof causes lateral separation of the laterally movable elements into frictional engagement with the inner surface of the housing.

Abstract: An apparatus for monitoring a reservoir. The apparatus can include a tube that is conveyable in a well, penetrating the reservoir. The apparatus can further include an expandable member coupled to the tube. The expandable member can expand upon exposure to a downhole trigger. A sensor can be coupled to the expandable member.

Abstract: A method and apparatus are provided for insulating electrical connections to a resonator from fluid downhole under extreme pressure and temperature conditions downhole. The method and apparatus provide a pliable insulator that maintains electrical isolation between a resonator electrical connection during exposure to high pressures downhole. The insulator is substantially chemically non reactive so that the insulator maintains electrical isolation between the resonator electrical connections during exposure to fluids downhole. The insulator has a thermal coefficient of expansion in a range so that the insulator maintains electrical isolation between the resonator electrical connections during exposure to high temperatures downhole.

Abstract: A method for conducting nondestructive internal inspection of a rotary drill bit used for drilling subterranean formations comprises communicating ultrasonic waves into a drill bit and detecting ultrasonic waves that are reflected by at least a portion of the drill bit. In some embodiments, the waves may be directed into the drill bit from within a longitudinal bore thereof. Reflected waves also may be detected from within the bore. The methods may be used to develop threshold acceptance criteria for classifying drill bits as acceptable or unacceptable to prevent catastrophic failures of drill bits during use. Systems and apparatuses are disclosed for conducting nondestructive ultrasonic inspection of a drill bit used for drilling subterranean formations. The systems and apparatuses may comprise an ultrasonic probe configured for insertion within an internal longitudinal bore of a drill bit. Drill bits are disclosed that are configured to facilitate nondestructive ultrasonic inspection thereof.

Abstract: A system and method is provided for communicating with a device disposed in a wellbore. Signals are sent through the Earth via signal pulses. The pulses are created by a seismic vibrator and processed by a receiver disposed in the wellbore. The receiver is in communication with the device and transfers data, such as command and control signal, to the device.

Abstract: Techniques for evaluating physical aspects of a formation fluid from within a wellbore include changing pressure on a sample of the formation fluid and transmitting at least one acoustic pulse through the fluid sample and analyzing acoustic information collected. Apparatus and methods for the evaluating involve using at least one acoustic transducer. Analyzing typically involves use of formulae that relate the fluid's equation of state and other properties to a change in the sound speed in the fluid as a function of pressure.

Abstract: An acoustic sensor for use in a downhole measurement tool includes a piezo-composite transducer element. In various exemplary embodiments, the acoustic sensor further includes a composite backing layer, at least one matching layer, and a barrier layer deployed at an outermost surface of the sensor. Exemplary embodiments of this invention may advantageously withstand the extreme temperatures, pressures, and mechanical shocks frequent in downhole environments and thus may exhibit improved reliability. Exemplary embodiment of this invention may further provide improved signal to noise characteristics. Methods for fabricating acoustic sensors and downhole measurement tools are also provided.

Abstract: Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture are described. According to one embodiment, an earth analysis method includes engaging a device with the earth, analyzing the earth in a single substantially lineal direction using the device during the engaging, and providing information regarding a subsurface feature of the earth using the analysis.

Abstract: In an exemplary implementation of a method and system for determining the direction of fluid flow, one or more sound transducers are positioned in proximity to a conduit, each such sound transducer generating a signal representative of a selected characteristic of acoustic waves emanating from the conduit. Such signals are collected and analyzed to determine a threshold value for the selected characteristic (e.g., frequency) indicative of a change in the direction of fluid flow through the conduit. Based on whether subsequent measurements of the selected characteristic (e.g., frequency) are above or below the threshold value, the direction of fluid flow can be predicted and/or a change in the operational state of a component associated with the conduit can be identified.

Abstract: Techniques for detecting a kick in a borehole include acquiring a set of measurements with a sonic tool in the borehole; determining borehole mud slowness from the set of measurements; and comparing the mud slowness with a selected criterion, wherein the determining the mud slowness includes determining fluid mode slowness as a function of frequency for at least one fluid mode, and determining the mud slowness from the fluid mode slowness.

Abstract: The present invention provides a chemometric equation to estimate fluid density, viscosity, dielectric constant and resistivity for a formation fluid sample downhole. The chemometric estimates can be used directly as estimated values for fluid density, viscosity, dielectric constant and resistivity for a formation fluid sample downhole. The chemometric estimates can also be plugged into a Levenberg-Marquardt (LM) non-linear least squares fit, as an initial estimate of the parameter to be estimated by the LM fit. If the initial parameter estimate is too far from the actual parameter values, the LM algorithm may take a long time to converge or even fail to converge entirely. The present invention estimates an initial value of a parameter that provides a high probability that the LM algorithm will converge to a global minimum.

Abstract: The present invention is directed to overcoming analog transmission difficulties by digitizing transducer signals at or near the transducer of an acoustic pulse gun and then transmitting the transducer signals in a digital form so that the signals can be recovered with greater fidelity by a remote computer or recorder. System, apparatus and method aspects of the invention are provided. Advantages of the present invention include better transmission of the acoustic signal from the pulse gun assembly to the computer or recorder, reduced noise and electronic interference, and better data capture.

Abstract: The present invention provides a downhole method and apparatus using a flexural mechanical resonator, for example, a tuning fork to provide real-time direct measurements and estimates of the viscosity, density and dielectric constant of formation fluid or filtrate in a hydrocarbon producing well. The present invention additionally provides a method and apparatus for monitoring cleanup from a leveling off of viscosity or density over time, measuring or estimating bubble point for formation fluid, measuring or estimating dew point for formation fluid, and determining the onset of asphaltene precipitation. The present invention also provides for intercalibration of plural pressure gauges used to determine a pressure differential downhole. A hard or inorganic coating is placed on the flexural mechanical resonator (such as a tuning fork) to reduce the effects of abrasion from sand particles suspended in the flowing fluid in which the flexural mechanical resonator is immersed.

Abstract: A parallel seismic tester utilizing a cone penetrometer to test the depth of a foundation or the like comprises three important elements: the cone penetrometer which houses a receiver, an impactor to impact the structure, and data gathering and analyzing equipment. The receiver may comprise a hydrophone, a geophone, or accelerometers. In the case where the receiver is a hydrophone, the hydrophone is embedded in a plastic, water filled container within the cone penetrometer head, and the head retracts prior to running tests.

Abstract: An acoustic sensor for use in a downhole measurement tool is provided. The acoustic sensor includes a piezo-composite transducer element. In various exemplary embodiments, the acoustic sensor further includes a composite backing layer, at least one matching layer, and a barrier layer deployed at an outermost surface of the sensor. Exemplary embodiments of this invention may advantageously withstand the extreme temperatures, pressures, and mechanical shocks frequent in downhole environments and thus may exhibit improved reliability. Exemplary embodiment of this invention may further provide improved signal to noise characteristics. Methods for fabricating acoustic sensors and downhole measurement tools are also provided.

Abstract: Tracking vibrations on a pipeline network includes installing multiple vibration recorders on the pipeline network, with each recorder including a sensor, a timer, a processor, and a digital communication device. At each vibration recorder, vibration signals are received from the sensor at programmed times under the control of the processor of the vibration recorders and processed by the processor. The processed vibration signals are communicated from the vibration recorder to a reader device using the digital communication device. Thereafter, the processed vibration signals from the one or more reader devices are collected at a central computer system. Finally, the collected processed vibrations signals are analyzed at the central computer system to determine abnormal vibration patterns and to obtain measures of any leaks present in the pipeline network.

Abstract: The present invention provides a downhole method and apparatus using a flexural mechanical resonator, for example, a tuning fork to provide real-time direct measurements and estimates of the viscosity, density and dielectric constant of formation fluid or filtrate in a hydrocarbon producing well. The present invention additionally provides a method and apparatus for monitoring cleanup from a leveling off of viscosity or density over time, measuring or estimating bubble point for formation fluid, measuring or estimating dew point for formation fluid, and determining the onset of asphaltene precipitation. The present invention also provides for intercalibration of plural pressure gauges used to determine a pressure differential downhole.

Abstract: The present invention provides a chemometric equation to estimate fluid density, viscosity, dielectric constant and resistivity for a formation fluid sample downhole. The chemometric estimates can be used directly as estimated values for fluid density, viscosity, dielectric constant and resistivity for a formation fluid sample downhole. The chemometric estimates can also be plugged into a Levenberg-Marquardt (LM) non-linear least squares fit, as an initial estimate of the parameter to be estimated by the LM fit. If the initial parameter estimate is too far from the actual parameter values, the LM algorithm may take a long time to converge or even fail to converge entirely. The present invention estimates an initial value of a parameter that provides a high probability that the LM algorithm will converge to a global minimum.

Abstract: The present invention discloses an acoustic resonator device capable of nucleating bubbles in a formation fluid under borehole-like conditions wherein the static pressure is higher than the bubble point pressure. The device is comprised of one or more coaxial layers forming a central conduit, wherein at least one of the coaxial layers is comprised of an electro-acoustic transducer material such as including piezoelectric or magnetorestrictive materials. This device is preferably designed to be in fluid communication with a host tool to allow in-situ sampling and bubble point determination. Also disclosed is an in-situ method of fluid analysis in a borehole for determining phase characteristics of a formation fluid using the device. Cavitation may be induced using the device in either a captured volume sample or a flow-line sample.

Abstract: The present invention discloses a method and apparatus to detect bubbles in a fluid sample to determine if gases are present, wherein an ultrasonic source is used and its properties monitored. Fluctuations in the ultrasonic source's electrical properties indicate the presence of bubbles/gas. Alternatively, the ultrasonic source may be used to cavitate the sample and induce the nucleation of bubbles. In such a system/method, bubbles may be detected by either (1) monitoring the ultrasonic source properties, (2) monitoring the compressibility of the sample, (3) monitoring the sample properties, including harmonics and subharmonics. The method and apparatus disclosed herein may be used in a borehole such as with a sampling means (including either a flowing sample or a stationary sample) or in a surface lab.

Abstract: The invention relates to a DFB fiber laser sensor (1). A measurement quantity makes it possible to induce a linear birefringence between mode pairs of the laser-amplifying fiber (2) and to measure an associated beat frequency (&Dgr;&ngr;1, &Dgr;&ngr;2, &Dgr;&ngr;3). According to the invention, the laser-amplifying fiber (2) has a nonrotationally symmetrical structure, so that it is possible to detect isotropic pressures p, acoustic waves or chemical substances that can be added radially to the laser-amplifying fiber (2). In a second aspect of the invention, an emission wavelength range and parameters (a, b, &Dgr;N) of the laser-amplifying fiber (2) and also a grating period L of the fiber Bragg grating resonator (3) are coordinated with one another such that at least two different spatial modes (LP01, LP11even, LP11odd, LP21even) are propagatable and it is possible to measure beat frequencies (&Dgr;&ngr;1, &Dgr;&ngr;2, &Dgr;&ngr;3) between oscillatory longitudinal laser modes assigned to them.

Abstract: An apparatus and system are disclosed for in situ measurement of downhole fluid flow using Doppler techniques. First, a baseline speed of sound is established as close to the desired measurement point as possible. This speed of sound measurement is then used in Doppler calculations for determining flow velocities based from induced Doppler shift resulting from fluid flow. A heterodyne receiver arrangement is preferably used for processing so that the flow direction can be determined and the detection sensitivity for low flow velocities can be enhanced. From in situ measurements, well kicks may be spotted and dealt with in real-time. In addition, current theoretical models of Theological properties may be verified and expounded upon using in situ downhole measurement techniques. Furthermore, the velocity measurements described herein can be used to recognize downhole lost circulation and/or gas/water/oil influxes as early as possible, even when the mud recirculation pumps are turned off.

Abstract: The present invention discloses an acoustic resonator device capable of nucleating bubbles in borehole-like conditions wherein the static pressure is higher than the bubble point pressure. The device is comprised of one or more coaxial layers forming a central conduit wherein at least one of the coaxial layers is comprised of an electro-acoustic transducer material. This device is preferably designed to be in fluid communication with a host tool to allow in-situ sampling and bubble point determination. Also disclosed is an in-situ method of fluid analysis in a borehole for determining phase characteristics of a formation fluid using the device. Cavitation may be induced using the device in either a captured volume sample or a flow-line sample.

Abstract: A method to analyze full waveform multiple (i.e., monopoles, dipoles, quadrupoles) acoustic measurements in a fluid-filled borehole, surrounded by a system of fractures oriented parallel to the axis of the borehole. The method uses new measurement attributes, herein referred to as dual flexure waves and leaky fracture mode.

Abstract: A method and apparatus for in-situ characterization of downhole fluids in a wellbore using ultrasonic acoustic signals. Measurements of the speed of sound, attenuation of the signal, and acoustic back-scattering are used to provide qualitative and quantitative data as to the composition, nature of solid particulates, compressibility, bubble point, and the oil/water ratio of the fluid. The tool generally comprises three sets of acoustic transducers mounted perpendicular to the direction of the flow. These transducers are capable of operating at different frequencies so that the spectrum of the acoustic signal can be optimized. The apparatus is capable of operating downhole to provide real time information as to conditions in the well.

Abstract: A method for downward communication in a borehole containing a pipe string, comprising the steps of: imparting a series of rotary motions to an upper portion of the string, the rotary motions representing at least two levels of a coded data sequence, the rotary motions imparted to a string upper portion effecting generally comparable motions at a lower portion of the string; the motions at the string lower portion effecting a downhole detectable condition or conditions indicative of rotation or no-rotation; detecting the condition or conditions to determine a corresponding coded data sequence; and processing corresponding data sequence to recover the imparted coded data sequence, from which a unique transmitted message is determinable.

Abstract: The invention relates to acoustic detection of leaks in a pipeline using locally-intelligent, data-adaptive monitors deployed for a period of time. Monitors are initialized by a base station. Following deployment, monitors receive vibration signals at programmed times, process the vibration signals to detect and characterize abnormal vibrations, and save the processed data in the monitor. Monitors may communicate digitally with a base station, sending processed data and receiving instructions. Alternatively, monitors may be removed from the pipeline and placed in a docking station prior to initialization and subsequent re-deployment on a pipeline. A procedural step of re-synchronization corrects for any mis-alignments in time that may occur among received vibration signals from different monitors. Received vibration signals from two or more monitors may then be analyzed using a correlative method to localize the position of any leaks present in the pipeline.

Abstract: The present invention finds the acoustic impedance of the drilling fluid using reflections from a precise metal disk, and therefrom the density of the drilling fluid. Because the reverberation characteristics of an acoustic wave depend in part on the acoustic wave shape, the first reflection from the metal disk may be used to calibrate the measurement. A method for determining a borehole fluid property is disclosed that includes (i) generating an acoustic signal within a borehole fluid, (ii) receiving reflections of the acoustic signal from the fluid, and (iii) analyzing a reverberation portion of the acoustic signal to determine the property. The analyzing of the reverberation portion may include obtaining a theoretical reverberation signal and relating the measured reverberation signal with the theoretical reverberation signal to determine the borehole fluid property.

Abstract: The present invention discloses a method and apparatus to detect bubbles in a fluid sample to determine if gases are present, wherein an ultrasonic source is used and its properties monitored. Fluctuations in the ultrasonic source's electrical properties indicate the presence of bubbles/gas. Alternatively, the ultrasonic source may be used to cavitate the sample and induce the nucleation of bubbles. In such a system/method, bubbles may be detected by either (1) monitoring the ultrasonic source properties, (2) monitoring the compressibility of the sample, (3) monitoring the sample properties, including harmonics and subharmonics. The method and apparatus disclosed herein may be used in a borehole such as with a sampling means (including either a flowing sample or a stationary sample) or in a surface lab.

Abstract: A system and method of fluid analysis in a hydrocarbon borehole is disclosed. Acoustic energy is emitted into the production fluid downhole at a level which causes a phase transition in the fluid. The pressure associated with the phase transition is determined using the level of emitted acoustic energy. Advantageously, the determination of the phase transition pressure need not rely on mechanical means to substantially alter the volume of a sample of the fluid. An acoustic transducer can be installed either semi-permanently or permanently downhole in the well. The bubble point or the dew point can be detected. In the case of bubble point detection, the bubbles in the fluid can be detected by sensing variations in impedance of the acoustic transducer, and the level of emitted acoustic energy can determined by measuring the electrical energy used to drive the transducer. A control system for a hydrocarbon well is also disclosed.

Abstract: A method to analyze full waveform multiple (i.e., monopoles, dipoles, quadrupoles) acoustic measurements in a fluid-filled borehole, surrounded by a system of fractures oriented parallel to the axis of the borehole. The method uses new measurement attributes, herein referred to as dual flexure waves and leaky fracture mode.