Abstract: Methods and apparatus for using multi-component geophones and/or multi-component geophone arrays to measure flow-induced acoustic energy produced in wellbores are provided. With the use of the multi-component geophones, the measured acoustic energy may be resolved into its directional components. The computed directional energy components may be mathematically compared to numerically highlight ambient flow conditions (e.g., leaks in casing or other conduit, points of fluid entry/exit/restrictions between the casing and the formation). The use of an array of multi-component geophones allows for the use of geophone move-out curves to further identify acoustic energy source locations.

Abstract: To determine properties of multiple oil and gas wells, oscillations at different test frequencies are applied to the flow rate and/or pressure of multiple wells. Measurements of flow rate and/or pressure and temperature in flows downstream of a production header of the multiple wells are then obtained. Such measurements from the flows of the multiple wells are subjected to a frequency analysis of the pressure, flow rate and/or temperature measurements to determine pressure, flow rate and/or temperature variations induced by the applied oscillations. Properties of the different wells of the multiple wells based on the results of the frequency analysis are thus determined.

Abstract: A method for modulating a downhole telemetry signal uses a fluid pressure pulse generator that generates pressure pulses of multiple pulse heights in a drilling fluid. The method comprises: converting measurement data into a bitstream comprising symbols of a selected symbol set; encoding the bitstream into a pressure pulse telemetry signal using a modulation technique that includes amplitude shift keying, wherein each symbol of the selected symbol set is assigned a pressure pulse having a unique amplitude; and generating pressure pulses in the drilling fluid corresponding to the telemetry signal. Alternatively, the method can comprise a modulation technique that includes amplitude shift keying and phase shift keying and wherein each symbol of the selected symbol set is assigned a pressure pulse having a unique combination of amplitude and phase.

Abstract: A seismic sensor for a downhole tool positionable in a wellbore penetrating a subterranean formation. The seismic sensor includes a sensor housing, a bobbin supported in the sensor housing along an axis thereof, at least one coil wound about the bobbin (the coil movably supportable within the sensor housing by at least one spring), at least one magnet positionable about the bobbin to generate a magnetic field with the at least one coil whereby seismic vibrations are detectable, and a filler fluid disposed in the sensor housing to buoy the at least one coil whereby gravitational effects may be neutralized.

Abstract: A flange bolt cutter for separating two connected flanges. The flange bolt cutter contains a circular saw blade connected to an flange mount which can be vertically adjusted relative to the flange mount and/or includes two arms which can be pivotally adjusted relative to each other.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate to measure compressional wave velocities in a geological formation surrounding a first well, to provide measured compressional wave velocity data, and to subsequently determine corrected compressional wave velocities for the first well. These corrected compressional wave velocities for the first well may be determined using a combination of the measured compressional wave velocity data and corrected compressional wave velocity data associated with one or more second wells. Predicted pore pressure data for the first well may be subsequently generated, using the corrected compressional wave velocities for the first well. Additional apparatus, systems, and methods are described.

Abstract: This invention comprises systems, methods and apparatus for mud pulse telemetry involving sending benchmark pulses with known characteristics (such as amplitude or duration) from the surface to the BHA, measuring those characteristics at the BHA, using those measurements to predict the likely attenuation of downhole-to-surface mud pulse transmissions, and adjusting those transmissions to compensate for high attenuation or to obtain energy savings (or transmission rate increases) during low-attenuation conditions. Further refinements on these systems and methods, particularly concerning the use of signal-to-noise ratio measurements at the surface to more efficiently predict attenuation, are also disclosed.

Abstract: A flow control system for drilling a well comprises a conduit defining a channel configured to accommodate a drill pipe and a flow of a returning drilling fluid, and an acoustic sensor array configured to detect a flow rate of the returning drilling fluid. The flow control system further comprises a flow control device configured to control the flow rate of the returning drilling fluid and to be actuated in response to an event detected by the sensor array, the flow control device being proximate to the sensor array.

Abstract: A stacked-ring, slow-wave acoustic telemetry isolation system and method for use with tubular assemblies such as drillpipe or production tubing comprising an acoustic wave transmitter, the acoustic isolator behaving such that a “down” wave propagated toward the isolator is reflected back substantially in phase with an “up” wave propagated from the acoustic wave source away from the isolator. The acoustic isolator is similarly effective in reflecting “up” propagating waves originating from below the isolator, hence further protecting the acoustic wave source from possible deleterious interference. It causes substantially all of the emitted wave energy to travel in a chosen direction along the drill pipe, thus aiding the efficiency of acoustic telemetry said pipe.

Abstract: A micro electromechanical systems (MEMS) sensor is excited. The response of the MEMS sensor is measured. The MEMS sensor is calibrated.

Abstract: A streamer for seismic prospection comprising directional sensors (20), such as geophones or accelerometers, distributed along the streamer, characterized in that said streamer comprises at least two tilt sensors (30, 40) located in remote positions and in locations distant from the directional sensors (20) and means which determined the effective orientation of each directional sensor (20) by interpolating along the streamer the tilt detected by the two tilt sensors (30, 40).

Abstract: An apparatus for acoustic imaging includes an array with a number of acoustic transducers. Each acoustic transducer transmits and receives acoustic signals. The apparatus also includes a control unit that is coupled to the array and selectively powers a number of acoustic transducers based upon standoff distance between the array and an object-of-interest (e.g., a borehole wall). In some embodiments, the control unit also varies the frequency of acoustic signals transmitted from the array using the standoff distance between the array and the object-of-interest.

Abstract: A method of automatic obstacle location mapping comprises receiving an indication of a feature to be identified in a defined area. An instance of the feature is found within an image. A report is then generated conveying the location of said feature.

Abstract: A downhole measurement tool includes at least one regular receiver and at least one reference receiver externally deployed on a tool body. The reference receiver is configured to be acoustically isolated from the borehole, for example, via an isolation structure including a high-impedance cap and a low-impedance gap. The reference receiver may be deployed in a linear array with the regular receiver(s) and may be substantially identical to the regular receiver(s) such that it has substantially the same sensitivity to tool mode signals and internal drilling noise as do the regular receivers. Received waveforms may be processed so as to remove tool mode arrivals and/or drilling noise.

Abstract: A value of a property of a fluid-filled wellbore system can be detected. This can be accomplished by recording data including at least one of pressure and rate of flow at one or more locations in the wellbore system, and then estimating the value of the property by employing a model for predicting at least one of pressure and rate of flow dependent upon characteristics and locations of disturbances to pressure and flow in the wellbore system, in order to determine a best prediction of some attribute of the recorded data.

Abstract: Apparatuses useable in an offshore drilling installation close to the seabed for controlling well influx within a wellbore are provided. An apparatus includes a centralizer and flow constrictor assembly, a sensor and a controller. The centralizer and flow constrictor assembly are configured to centralize a drill string within a drill riser and regulate a return mud flow. The sensor is located close to the centralizer and flow constrictor assembly and configured to acquire values of at least one parameter related to the return mud flow. The controller is coupled to the centralizer and flow constrictor assembly and the sensor. The controller is configured to control the centralizer and flow constrictor assembly to achieve a value of a control parameter close to a predetermined value, based on the values acquired by the sensor.

Abstract: Downhole seismic sources that may be compatible measurement-while-drilling systems. The downhole seismic sources are integrated into drill string components, including drill collars of the bottom hole assembly. The downhole seismic sources may generate a low swept frequency signal suitable for imaging around the drill-string and ahead of the drill bit. Integrated downhole seismic systems including a downhole seismic source, receivers and optionally data processing capabilities. The integrated systems may be configured to determine the distance and orientation of bed boundaries, including ahead of the drill bit up to about 200 m to 500 m in depth. Methods for downhole seismic, including single well and cross-well seismic. The methods may include obtaining seismic information ahead of the drill bit.

Abstract: A dipole source for borehole acoustic logging is provided, including a cylindrical shell, a center beam coupled to the cylindrical shell and a movable projector inside the cylindrical shell to impact the center beam. The dipole source includes a cavity acoustically insulating the interior of the cylindrical shell from the exterior of the cylindrical shell. An acoustic logging tool for making measurements of a substrate surrounding a borehole with a body insertable in the borehole is also provided. The body includes an acoustic detector and a dipole source as above, along the axial length. The acoustic logging tool may include a control unit to process data collected from the acoustic detector and obtain information about the substrate surrounding the borehole. According to embodiments disclosed herein, a method for operating a dipole source and an acoustic logging tool as above is provided.

Abstract: Neutrally-buoyant tools for seismic data collection are provided that may range from several hundred meters to several kilometers in length and have integrated sensors which move along with the borehole fluid in response to a passing seismic wave. The disclosure also provides methods of deploying neutrally-buoyant tools, which includes using a tractor, adding a weight or both to the tool in order to overcome the difficulty of lowering a neutrally buoyant tool into a borehole, and optionally occasionally clamping the tool to the borehole to alleviate tension in the tool. This disclosure also provides methods of acquiring seismic data, which involves positioning a neutrally-buoyant tool in a borehole such that the tool is able to move relatively freely along with the borehole fluid in response to a seismic wave passing through the fluid, firing a seismic source, and using the sensors to collect seismic data generated thereby.

Abstract: The disclosure addresses acoustic receivers including an acoustic isolator structure, and an acoustic logging tool which incorporates the acoustic receiver. The acoustic receiver isolation structure is configured to minimize acoustic transmissions which could otherwise adversely affect acoustical measurements being made by an acoustic receiver. The described acoustic receiver includes a plurality of longitudinally arranged mass members coupled to a central supporting structure, in a configuration to reduce acoustic transmissions in at least selected frequency ranges.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate to measure compressional wave velocities in a geological formation surrounding a first well, to provide measured compressional wave velocity data, and to subsequently determine corrected compressional wave velocities for the first well. These corrected compressional wave velocities for the first well may be determined using a combination of the measured compressional wave velocity data and corrected compressional wave velocity data associated with one or more second wells. Predicted pore pressure data for the first well may be subsequently generated, using the corrected compressional wave velocities for the first well. Additional apparatus, systems, and methods are described.

Abstract: The present disclosure is related to apparatuses and methods measuring and processing a characteristic of subsurface earth formations penetrated by a borehole. More specifically this present disclosure relates to a method and apparatus for measuring and processing an acoustic characteristic such as formation shear wave velocity of subsurface sonic waves after these waves traverse earth formations adjoining a borehole or passing through a portion of the subsurface. The apparatus may include: a bottomhole assembly, a drill bit configured to generate an acoustic signal, at least two acoustic detectors, and a processor. The acoustic signal may include a specific multipole signal that may propagate through an earth formation along the borehole. The method may include use of the apparatus, including steps for estimating a shear velocity of the acoustic signal using signals from the at least two acoustic detectors.

Abstract: Methods and apparatus for performing sonic well logging within a wellbore based on optical Distributed Acoustic Sensing (DAS) are provided. A sonic well logging system based on DAS may be capable of producing the functional equivalent of tens, hundreds, or even thousands of acoustic sensors. In this manner, the emplacement of the sonic well logging system based on DAS may not be nearly as complex or expensive as emplacing a sonic well logging system based on traditional methods. Furthermore, multiplexing may be simpler, downhole electronics need not be used, and the sonic well logging system may be used in extreme, high temperature environments.

Abstract: Embodiments of this invention relate to compositions and methods of processing a subterranean formation including collecting microseismic data from one wellbore, collecting amplitude ratio information for the microseismic data, comparing the amplitude ratio to an expected ratio, generating a representation of a formation based on the microseismic data and the comparison of the amplitude ratio and expected ratio, and performing an oil field services activity based on the representation.

Abstract: A logging tool for use in a wellbore having a sensor portion for making measurements. The tool has a sleeve enclosing the sensor portion and made of a material that is transparent to the measurements being made. One or more structural elements having physical characteristics different from the material comprising the sleeve are carried on the sleeve to enhance the mechanical properties of the sleeve.

Abstract: A method and apparatus for determining the location of a material located behind an obstruction. A plurality of acoustic resonators (6) having a known resonant frequency are dispersed in the material (3), the material to be located on a first side of the obstruction (2). An instrument (5) is provided at an opposite side of the obstruction to the material. The instrument emits an acoustic signal and measures a response. If the resonant frequency is detected, it is determined that the material is located substantially adjacent to the instrument. The apparatus may be used for determining the height of cement slurry located between a well casing wall and a borehole.

Abstract: A method and apparatus for determining the fluid permeability of an earth formation is described. An instrument comprising an acoustic source and acoustic and electrokinetic sensors is located in a borehole at a site of interest. The acoustic source is fired and the resulting variations in pressure and electric field generated are measured and recorded. The Biot equation, and an equation for the streaming potential coupled to fluid displacement terms, is solved using finite element analysis to give an expected pressure waveform and electrokinetic waveform based on estimated earth formation properties. By comparison of the measured waveforms and those calculated from the equations, the actual permeability of the earth formation can be deduced.

Abstract: Refracted ultrasonic waves are utilized to calculate tool standoff. An ultrasonic transmitter sends a wave toward (and into) the borehole wall at a critical incidence angle for refracted waves. The refracted wave travels along the borehole wall and continuously radiates energy back into the borehole at the critical angle. The refracted wave is detected by a receiver, and the travel time of the refracted acoustic wave from transmitter to receiver is measured and used to calculate standoff. By making repeated measurements at various azimuths (for instance, as the tool rotates), one or more caliper measurements can be made. The caliper measurements can be combined to yield two-dimensional geometry of the borehole. Measurements made at different azimuths and depths yield three-dimensional borehole geometry. Arrays of transmitter-receiver pairs can be used to obviate the need for varying azimuth.

Abstract: An acoustic attenuator assembly for an acoustic tool for performing acoustic investigation of a subterranean formation is disclosed. The acoustic attenuator assembly includes a first end portion (205) and a second end portion (215) having a bore therethrough to enable passage of an electrical line. The acoustic attenuator assembly further includes a fiber portion (230) disposed between the first and second end portion so that the fiber portion attenuates at least a portion of acoustic energy when the acoustic energy is received by one or both of the first (205) and second (215) end portions.

Abstract: Methods and systems for acoustically determining reservoir parameters of subterranean formations. A tool comprising at least one seismic source or seismic receiver mounted thereon; a conveyance configured for movement of the acoustic tool in a borehole traversing the subterranean formations; and a source retainer configured or designed for permanent deployment in the borehole to removably retain the acoustic tool in the borehole. The source retainer when deployed provides acoustic coupling with the borehole and removably retains the acoustic tool in the borehole so that, over multiple deployments, the acoustic tool is repeatedly deployed at the same predetermined location and orientation relative to the subterranean formation, and with the same acoustic coupling to the borehole.

Abstract: Temperature and pressure measurements that are made downhole are used to predict a compressional wave velocity for pure water under downhole conditions. The predicted velocity and a measured compressional velocity of a formation brine are used in a non-iterative method to estimate a value of the formation brine salinity that is between 0 and 1.

Abstract: A downhole tool for subsurface disposal is provided. The tool comprises an elongated tool body, an enclosure attached to an exterior surface of the tool body. The enclosure comprises at least one transducer disposed at an angle with respect to a longitudinal axis of the enclosure, and an electronics board coupled to and disposed adjacent to the at least one transducer. The enclosure also defines an internal cavity, and the internal cavity contains a fluid for insulating the at least one transducer from a downhole environment. The fluid is in direct contact with the at least one transducer and the electronics board.

Abstract: An acoustic energy source for imparting acoustic energy into the Earth's subsurface includes an electrically driven transducer coupled to a source of swept frequency alternating current. A tunable Helmholtz resonator is disposed proximate the transducer. In one example, the resonator has a tuning device configured to maintain a resonant frequency substantially equal to an instantaneous frequency of the alternating current. The tuning device includes an actuator coupled to a sleeve, wherein the sleeve is disposed over selected numbers of openings in a wall of a tube on the resonator. The transducer and the resonator are disposed in a wellbore drilled through rock formations. The wellbore has a plurality of layers of fluid therein, each layer thereof having a different density and/or viscosity.

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: An acoustic isolator for use with tubular assemblies such as drillpipe or production tubing comprising an acoustic wave transmitter, the acoustic isolator comprising, in series connection, an odd integer ?/4 multiple tuning bar of first acoustic impedance adjacent the acoustic wave transmitter, an odd integer ?/4 multiple reflector tube of second acoustic impedance, and a snubber of third acoustic impedance, wherein there is an acoustic impedance mismatch between the odd integer ?/4 multiple tuning bar and the odd integer ?/4 multiple reflector tube and an acoustic impedance mismatch between the odd integer ?/4 multiple reflector tube and snubber, such that a ‘down’ wave propagated toward the isolator is reflected back substantially in phase with an ‘up’ wave propagated from the acoustic wave source away from the isolator.

Abstract: A method for attenuating out of band energy emitted from a seismic source used in a marine seismic survey. The method includes disposing the seismic source in a body of water and releasing a gas into a volume of water surrounding the seismic source. The released gas may be configured such that it displaces the volume of water surrounding the seismic source at a rate less than 2.9×106 cubic-meters per cubic-second.

Abstract: An enclosure for housing a transducer and electronics for disposal on a downhole tool. A transducer is disposed at an angle with respect to a longitudinal axis of the enclosure, wherein the enclosure contains a fluid surrounding the transducer. Enclosures also include transducers linked to motor means for selective rotation of the transducers within the enclosure. Enclosures with transducer arrays for phased or targeted signal transmission/detection.

Abstract: A system for communicating with downhole tools and devices is disclosed. The system includes multiple communication devices which, in combination, permit operators at the surface to operate downhole tools and to receive feedback regarding the state of the tools.

Abstract: An acoustic isolator section for an acoustic well logging tool, the isolator section comprising: an isolator comprising: (i) an isolator body; (ii) a mass; (iii) a resiliently deformable portion formed integrally with the isolator body; (iv) a movement limiter.

Abstract: A method for attenuating out of band energy emitted from a seismic source used in a marine seismic survey. The method includes disposing the seismic source in a body of water and releasing a gas into a volume of water surrounding the seismic source. The released gas may be configured such that it displaces the volume of water surrounding the seismic source at a rate less than 2.9×106 cubic-meters per cubic-second.

Abstract: Multipole acoustic logging-while-drilling (LWD) tools and associated methods are disclosed herein. In some embodiments, the disclosed acoustic LWD tool comprises a transmitter array and at least one receiver array. The transmitter array generates acoustic waves with an excitation pattern having a cutoff frequency greater than about 3 kHz. The receiver array is spaced apart from the transmitter array and is configured to detect said acoustic waves. Some of the disclosed method embodiments comprise: generating multipole acoustic waves in a fluid-filled borehole using an excitation pattern with a cutoff frequency greater than about 3 kHz; selectively detecting acoustic waves that propagate with said excitation pattern; and determining an acoustic shear wave slowness for a formation penetrated by the borehole.

Abstract: Method for identifying one or more fracture clusters in a formation surrounding a reservoir. In one implementation, the method may include generating a P to S image, comparing the P to S image to one or more images from a borehole, and identifying one or more fracture clusters using the P to S image and the borehole images.

Abstract: Deploying systems and methods for deploying a plurality of seismic devices into a borehole comprising a cable including a plurality of inter-connected cable segments and ellipsoid seismic units with at least two rows of offset seismic protrusions to establish at least three points of contact between the seismic units and adjacent cylindrical surface of a borehole casing.

Abstract: To process measurement data representing a subterranean structure, a derivative of the measurement data collected by at least one survey receiver is computed, with respect to frequency. A response representing the subterranean structure is then computed based on the derivative of the measurement data, where the response contains an air-wave component that has been suppressed due to computing the derivative of the measurement data relative to at least another component that is sensitive to the subterranean structure.

Abstract: An attenuation apparatus, system, and method are disclosed. The attenuator is attached to a pipe and includes a housing that includes an inner sleeve and an outer sleeve. The attenuator includes one or more masses, to resonate when exposed to waves including acoustic frequency components.

Abstract: Stoneley-wave data acquired in the LWD environment are used to characterize/estimate formation permeability. Real-time Stoneley-wave time-delay/slowness and center-frequency/attenuation data are used to indicate/characterize formation permeability even during drilling. The use of stabilizers mounted at the tool ends helps maintain the tool position from severe decentralization, reducing ambiguities in the permeability characterization/estimation.

Abstract: A measurement package for disposal on an apparatus such as a downhole tool or a tool like device. The measurement package including an enclosure, a first acoustic transducer housed within the enclosure, a second acoustic transducer housed within the enclosure and electronics housed within the enclosure that is in communication with the first and second transducers. Further, an acoustic transmitter and receivers can be disposed at an angle with respect to a longitudinal axis of the enclosure. The enclosure can contain attenuative material surrounding the transmitter and receivers, and electronics for controlling the transmitter and receivers and communicating with the downhole tool.

Abstract: A method for initializing the input of each of m receiver channels of a receiving transducer in a well logging tool comprising the steps of selecting a logging tool having a multi-element receiving transducer wherein each element of the multi-element receiving transducer operates in an anti-resonant mode below its resonant frequency, and executing a routine in an initialization mode wherein a predetermined number of run cycles are operated and receiver input responses are measured and averaged for each of the m channels while transmitter firing signals are disabled.

Abstract: A method and a system for determining the position of a drill bit are presented. The method comprises determining positions of seismic wave detectors, recording seismic waves generated at the drill bit, identifying events at the drill bit, determining a plurality of relative positions of the drill bit, and determining, based at least partly on a starting position and a sum of the relative positions, an absolute position of the drill bit. The method further comprises determining a position of the drill bit at a second event in relation to a position of the drill bit at a first event, and determining a second seismic wave propagation velocity between the drill bit and at least one of the detectors, based at least partly on the determined position of the drill bit at the second event.

Abstract: A monopole acoustic transmitter with at least one disc assembly with a plurality of piezoelectric discs configured to optimized acoustic pressure output within a desired frequency range while meeting physical restrictions of LWD and MWD logging systems. The transmitter is disposed in a recess or “slot” in the perimeter of a logging tool housing to reduce acoustic pressure waves transmitted directly along the tool housing and to optimize acoustic energy transmission into the borehole environs. In order to increase acoustic pressure output at a desired logging frequency range, the plurality of piezoelectric discs in each of at least one disc assembly are connected electrically in parallel and fired simultaneously. The polarity of the discs and the wiring arrangement are such that each disc expands or contracts in a common direction during simultaneous firing by an applied voltage.