Abstract: A well completion system can include fluid flow through a flow passage, and one or more diverters deployed into the flow passage downhole of a perforating assembly, the diverters and the perforating assembly being concurrently displaced by the fluid flow. A perforating assembly can include a perforator, and a control module including a memory, a motion sensor, a timer, and a controller that causes the perforator to fire in response to a lack of motion for a predetermined period of time. A well completion method can include flowing fluid through a flow passage, deploying a perforating assembly into the flow passage, and displacing the perforating assembly through the flow passage by the fluid flow at a predetermined flow rate for a predetermined flow time, and ceasing the fluid flow at an end of the predetermined flow time, thereby placing the perforating assembly at a desired location for forming perforations.

Abstract: A non-destructive method uses ultrasound measurements to determine some mechanical properties of an elastomeric material. The measurements can be made during manufacture of the elastomer for quality control purposes. The measurements can also be made on the elastomeric material in situ as part of a device to assess degradation of the elastomer over time.

Abstract: Discrete wellbore devices, hydrocarbon wells including a downhole communication network and the discrete wellbore devices, and systems and methods including the same are disclosed herein. The discrete wellbore devices include a wellbore tool and a communication device. The wellbore tool is configured to perform a downhole operation within a wellbore conduit that is defined by a wellbore tubular of the hydrocarbon well. The communication device is operatively coupled for movement with the wellbore tool within the wellbore conduit. The communication device is configured to communicate with a downhole communication network that extends along the wellbore tubular via a wireless communication signal. The methods include actively and/or passively detecting a location of the discrete wellbore device within the wellbore conduit. The methods additionally or alternatively include wireless communication between the discrete wellbore device and the downhole communication network.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate to transmit energy as transmitted signals from current electrodes on a galvanic down hole tool, while multiplexing the energy in both time and frequency domains, to interact the transmitted signals with a geological formation to provide interacted signals that represent a formation property. Additional apparatus, systems, and methods are described.

Abstract: A method for operating an impulsive type seismic energy source in a firing sequence having at least two actuations for each seismic impulse to be generated by the source. The actuations have a time delay between them related to a selected energy frequency peak of the source output. One example of the method is used for generating seismic signals in a wellbore and includes discharging electric current through a spark gap disposed in the wellbore in at least one firing sequence. The sequence includes at least two actuations of the spark gap separated by an amount of time selected to cause acoustic energy resulting from the actuations to have peak amplitude at a selected frequency.

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: A system, method and device may be used to monitor acoustic energy in a borehole. Electromagnetic energy is used to energize a resonant circuit incorporating a sensor. The sensor modulates the electromagnetic energy in accordance with received acoustic energy and transmits the modulated energy so that it may be received and processed in order to obtain the desired measurements.

Abstract: Tubewaves are used to transmit an indication of the depth at which a condition is detected in a well. In particular, the depth is calculated based on the difference in arrival time at the surface of a first tubewave which propagates directly upward in the borehole and a second tubewave which initially travels downward and is then reflected upward. The tubewaves may be generated by a canister designed to implode at a certain pressure. After being introduced into the flowline at an above ground inlet, the canister is carried downhole by gravity and the fluid being pumped. When the canister reaches a depth at which its pressure tolerance is exceeded, it implodes and generates the tubewaves. An analyzer at the surface detects the tubewaves with a hydrophone array and generates a pressure versus depth profile of the well, i.e., one data point for each implosion.

Abstract: In a subterranean well completion a bi-directional signal transmission system includes an in-line acoustic transceiver mounted in a tubing string extending through the wellbore, the transceiver being disposed beneath a hanger structure engaging the tubing string. Via the tubing string the transceiver receives acoustic signals from well parameter sensing apparatus further downhole and converts the received acoustic signals to non-acoustic signals. The resulting non-acoustic signals are then transmitted upwardly through the hanger structure, to a signal receiving location, via cabling. In this manner, the hanger structure does not adversely affect the strength of either upwardly or downwardly transmitted signals traversing it. Alternatively, the acoustic well parameter signals received by the transceiver are converted to electromagnetic signals which pass through the earth, are picked up by a receiver external to the well completion, and then relayed to the receiving location.

Abstract: The present invention provides a method of performing the time picking step in a VSP (vertical seismic profile) survey. In a preferred embodiment of the invention the time picking step is carried out on a combined three-component amplitude of the received seismic energy, which contains the amplitude of all the seismic energy received at the receiver. The amplitude of the direct pulse in the combined trace will not decrease to zero as the offset of the source is changed, as can be the case for the single-component amplitude of the direct pulse. In a particularly preferred embodiment of the invention, the combined three-component amplitude is calculated by summing the Hilbert instantaneous amplitudes of the x-, y- and components of the seismic data using the equation (I). The present invention also provides two new time picks. One time pick involves finding the maximum positive gradient of A(t).

Abstract: The present invention provides a semi-passive two-way borehole communication system and method. The system includes a surface source signal generator for generating an acoustic signal. The acoustic source signal is transmitted downhole, and a downhole controllable reflector reflects a portion of the source signal back toward the surface. The reflector is controlled such that an echo signal is created, which contains information to be carried to the surface. A surface receiver is used to detect the echo signal, and a surface controller is used to decode the echo signal.

Abstract: An excitation event in an oil, gas or geothermal well creates a responsive signal having lower and higher frequency components, which higher frequency component provides information about one or more characteristics of the well. Examples of such characteristics pertaining to a subterranean fracture include: breakdown pressure at fracture initiation, time it takes proppant to reach and to screenout the tip of the fracture, fracture geometry and fracture growth, fracture closure pressure, relative fluid flow through respective perforations, and horsepower requirements to perform a fracture treatment. One excitation event includes creating an excitation signal having a maximum amplitude change occurring within a time t1, which is less than a period t2 of the higher frequency component. Wavelet processing may be used to separate or distinguish the higher frequency waveform from the lower frequency waveform.

Abstract: Embodiments of the present invention generally provide an apparatus, method, and system for operating an electric downhole tool on a non-conductive support line (slickline) by converting a battery voltage to an output voltage suitable for operating the tool. In response to receiving a trigger signal, the output voltage signal is applied to the tool. The tool is controlled by varying the output voltage signal according to a power control sequence. Accordingly, electric tools typically requiring surface intervention by an operator via an electric cable (wireline) may be operated on slickline.

Abstract: An acoustic tool that provides a programmable source waveform is disclosed. Numerous advantages may be achieved from the configurability of the source waveform. Notably, acoustic logs at multiple frequencies may be acquired with a single pass. The waveform may be frequency-adapted to maximize formation response and amplitude adapted for gain control. In one embodiment, the acoustic tool comprises: a controller, a digital-to-analog controller (DAC), an acoustic transducer, and a linear driver. The DAC converts a digital waveform from the controller into an analog waveform. The acoustic transducer converts an electrical signal into an acoustic signal. The linear driver receives the analog waveform from the DAC and responsively provides the electrical signal to the acoustic transducer. The electrical signal is proportional to the analog waveform. The tool may further include a memory for storing the digital waveform and/or software for generating the digital waveform.

Abstract: A measuring device for measuring the elastic properties of a surface structure (3), comprising a probe (2) arranged within a housing (1), a transmitter and at least one receiver, the transmitter transmitting acoustic pulses and the receiver picking up the propagation behavior of the acoustic pulses in the surface structure (3), a control means (16) for generating acoustic pulses and an evaluating means (18) for the measuring signals received by the receiver, at least two adjacent measuring tips (4, 6) being connected as transmitting and receiving elements, the measuring tips being adapted to be set onto the surface structure (3) and having strip-shaped bi-morph elements (12, 14) carried by a holder (8, 10), wherein the measuring tips (4,6) are formed by the holders (8, 10) of the bi-morph elements (12, 14) and the strip-shaped elements (12, 14) have one side of one of their ends fastened to the holder (8, 10).

Abstract: A wireline acoustic probe and associated methods provide enhanced calibration and communication capabilities in a downhole acoustic communication system. In a described embodiment, an acoustic probe is conveyed on a wireline to a position proximate a downhole acoustic transmitter. A command is transmitted acoustically from the probe to the transmitter, causing the transmitter to generate acoustic frequency sweeps. The sweeps are received by the probe proximate a downhole acoustic receiver, permitting an optimum acoustic transmission frequency to be selected.

Abstract: The invention is a method and apparatus for acoustic logging including one or more acoustic transmitters and one or more acoustic receivers. One or more of the elements of a set made up of the acoustic receivers and acoustic transmitters are spaced radially apart from one or more of the remaining elements of the set. The acoustic receivers and acoustic transmitters are configured along with electronics and software incorporated in the tool to allow the acoustic receivers and acoustic transmitters to act as multi-pole receivers and multi-pole transmitters, respectively. The tool is configured to compute one or more acoustic velocities and to provide storage for unprocessed and processed, compressed and error correction coded data. The tool is configured to provide the data for transmission to the surface.

Abstract: A vertical seismic profiling system includes seismic receivers for placement on a drillstring and surface seismic sources. One-way checkshot data may thus be measured without tripping the drillstring. A downhole acoustic tool measures the local interval transit time of the formation, and improves the detection of targets ahead of the drill bit. The local interval transit time may be applied to the time of travel from reflections in front of the bit to establish distance to the bit. The down-going wavetrain may be deconvolved with the total up-going wavetrain to extract the nearest reflector and the relative acoustic impedance at the reflector. A synthetic seismogram may also be created based on reflection depth data and corrected with checkshot data.

Abstract: Systems are disclosed for securing near vertically deployed seismic detector systems in a cased well borehole from oscillatory motion during a seismic survey. In one embodiment a generally cylindrical body member of an unsymmetrical shape having one flat side is used opposite a selectably extensible backup locking arm. In a second embodiment a generally symmetrical cylindrical body member having sets of four essentially coplanar contacting feet disposed at 90 degree circumferential spacing an opposite ends is provided. The sets of locking feet on opposite ends of the tool body member are phased 45 degrees apart circumferentially with respect to each other. Locking edges and feet may be magnetically assisted if desired.

Abstract: A downhole acoustic logging tool having a random access memory for storing acoustic waveforms in digital format. The waveforms being transmitted from a surface logging system to the random access memory in the downhole logging tool. The logging tool playing back the stored waveforms by converting the stored digital format into an analog signal that is amplified sufficiently for driving an acoustic transmitter. A received pilot signal is used to determine the signal attenuation of the logging cable and a correction is made therefrom to the actual received acoustic signal. Complex waveform types may be programmed into the random access memory for specific formation characteristics. Tapered turn-on and turn-off of the signal waveform amplitudes reduce higher frequency spectral noise that may interfere when correlating the received acoustic signal with the transmitted acoustic signal.

Abstract: A method and apparatus for communicating coded messages in a wellbore between a transmission node and a reception node is provided. The coded messages are messages are impressed upon a fluid column which extends between the transmission node and the reception node. A transmission apparatus is provided at the transmission node which is in communication with the fluid column, for altering pressure of the fluid column to generate at least a portion of the coded message. A reception apparatus is provided at the reception node. The reception apparatus includes a rigid structural component with an exterior surface which is in direct contact with fluid column and an interior surface which is not in contact with the fluid column, and a sensor assembly which detects elastic deformation of the rigid structural component. The transmission apparatus is utilized to alter pressure of the fluid column in a predetermined pattern to generate at least one coded message.

Abstract: A borehole televiewer is modified to provide an improved signal-to-noise ratio by utilizing a series of receivers arranged in a planar array configuration with respect to a centrally located transmitting transducer. The array covers at least a 90.degree. quadrant of the tool, extending approximately 45.degree. on either side of the transducer to allow the receivers to capture all primarily reflected signals, both the specular component as well as the vertical and horizontal components of the scattered reflections. The signal-to-noise ratio is further enhanced by the use of a noise-dependent timing means, as well as signal conditioning and detection circuits for each of the receivers in the array.

Abstract: A borehole logging tool having a dipole acoustic energy source and at least one spaced-apart dipole acoustic energy receiver is lowered into a deviated borehole. A motor rotates the source and receiver about the axis of the borehole tool. A first signal is produced representing source and receiver rotational position relative to a vertical direction. A second signal is produced representing a fixed reference level. A comparator produces a third signal of the difference between the first and second signals. The motor rotates so as to minimize such third signal, thereby maintaining the focus of the source and receiver in a horizontal direction that is perpendicular to the direction of eccentricity of the borehole tool with respect to the borehole axis.

Abstract: A seismic logging system for VSP or cross well data capture set forth. It is comprised of M duplicate recording stations connected serially below a main structure suspended on a logging cable. Each of the recording stations preferably includes orthogonally arranged displacement transducers, and they are in turn connected with suitable amplifiers, filters and converters to form digital words, and the digital words are recorded in organized fashion in a memory. A telemetry unit is connected to that memory for transfer of data. This data transfer takes place over a short distance into the main unit, and the main unit includes a much larger memory for storing and holding data from M recording stations deployed along and there below in the well borehole, and further including telemetry means for transfer of data along the logging cable.

Abstract: In a representative embodiment of the invention described herein, a well logging system for investigating subsurface formations is controlled by a general purpose computer programmed for real-time operation. The system is cooperatively arranged to provide for all aspects of a well logging operation, such as data acquisition and processing, tool control, information or data storage, and data presentation as a well logging tool is moved through a wellbore. The computer controlling the system is programmed to provide for data acquisition and tool control commands in direct response to asynchronous real-time external events. Such real-time external events may occur, for example, as a result of movement of the logging tool over a selected depth interval, or in response to requests or commands directed to the system by the well logging engineer by means of keyboard input.

Abstract: An acoustin transducer system for a borehole televiewing apparatus is set forth. In the preferred embodiment, a ceramic circular disc is used and is divided by grooves selected thereon into a set of N concentric rings where N is a whole number integer. Each ring has its own associated transmitter and they are fired in a controlled sequence. Each ring operates as a receiver, and they form output signals which are amplified and controlled delay at the respective delay lines, the several output signals are summed. This assures that the illuminated regions of the borehole is in focus and has a greater depth of field. And a method is also described whereby multiple simultaneous electronically formed acoustic beams are utilized in a differential mode to achieve high spatial resolution in time of flight measurements.

Abstract: A method and apparatus for geophysical exploration wherein a seismic wave is passed through a bore hole so at to sequentially detonate a plurality of explosive charges disposed within said bore hole at spaced intervals. A preselected seismic wave magnitude represented by a stored voltage is compared with signals generated by electro-acoustic sensors associated with each charge. When the magnitude of a seismic wave in the bore hole equals the preselected magnitude, a voltage stored on a capacitor discharges into a detonator. Means are provided for varying the stored voltage representing the preselected magnitude from the surface of the bore hole and for detonating any unexploded charges which may after the initial seismic wave passes through the bore hole. A firing circuit is armed substantially simultaneously with the initiation of the seismic wave in the bore hole. The firing circuit is armed for only approximately 0.1 to 0.5 seconds thereby preventing late detonation which destroys seismic data.

Abstract: Multiple downhole seismic signals are generated by an apparatus comprising one or more elongated rod segments insertable in a borehole and provide with spaced-apart predetermined lengths of Primacord explosive charge helically wrapped on the exterior of the rod segment and spaced apart by circumferential baffles supported on the rod segment. The charges are selectively fired through a motor actuated selector switch and a switch stepping and firing circuit including only two conductors and blocking diodes for imposing signals of opposite polarity on the selector switch and its actuating motor.

Abstract: The power-conversing apparatus includes a plurality of independently energizable electrical circuits used in receiving electrical signals from a transducer which senses an environmental condition, in processing the electrical signals, and in storing information related to the detected environmental condition. The apparatus further includes a power control circuit for continuously providing electrical power to at least one of the electrical circuits and for independently switchably providing electrical power to selectable ones of at least two others of the separately energizable circuits.

Abstract: A 60 to 100% coverage of downhole casing condition is obtainable by the improved system comprising, a sufficient number of piezoelectric transducers 1/4 inch in diameter about a probe head, preferably, 40 or more and usually 60-120 piezoelectric transducers located in a housing coupled to an electronic package also in a suitable downhole housing. The system reports all exceptional data and certain selected regular or non-exceptional data, displaying it topside and establishing a permanent record using existing wire line facilities.

Abstract: A seismic geophysical prospecting method and apparatus is described involving the sequential shooting of lump explosive charges spaced apart in a borehole so as to produce seismic wave reinforcement in a given direction. Fast acting electronic switch means control the detonation of each charge responsive to the advance of the seismic waves front substantially independent of formation pressure wave velocity.

Abstract: A method and apparatus for encoding and synchronizing and sequencing pulse encoded data in a pulse telemetry system. The time intervals between successive pulses in a pulse train are representative of the magnitude of the data parameters. Redundant pulses are included in the pulse trains at predetermined time locations with respect to the pulses so as to enhance the ability to recognize or distinguish data pulses over noise signals. Synchronization pulses are employed to enable identification of the particular data parameters even though one or more of the data pulses is obscured by noise. The sequence of the production of the pulse code signals is continuously monitored to enable the telemetering system to be activated promptly after a shutdown at the place in the train of data where it would be if the shutdown had not occurred.

Abstract: The shear wave source of this invention includes a housing and means for applying forces to the shot hole wall. The force applying means applies a number of forces to the shot hole wall along lines normal to a plane close to the shot hole. No pressure waves, but only shear waves are generated at distant points on the plane. At least one of the forces is applied in opposite direction to the other forces to reduce the net recoil of the housing.A first, second and third force are applied at three source points in the observation plane along three lines normal to the plane to generate respectively a first, second and third shear wave in the plane. The first and third forces are equal in magnitude and the second force has twice the magnitude of the first force. The first and third forces are applied along lines in the same direction, but the second force is applied along a line opposite in direction to the lines of the first and third forces.

Abstract: A telemetering system provides improved cable utilization and bi-directional digital communication between a logging sonde and surface electronics over a single balanced transmission line of a multi-conductor logging cable, with significant signal crosstalk reductions. Receiver circuitry downhole decodes pulses delivered on the line from a surface logic generator which fire transmitter-receiver pairs of an acoustic logging tool in an order defined by the pulses. A PCM transmitter in the sonde thereafter samples data generated by other logging instruments, encodes this information into digital data frames, and transmits the data on the same line to a surface PCM receiver. Circuitry limits surface and downhole receiver response to PCM transmitter and logic generator pulses, respectively. A center tap of the same transmission line also provides for simultaneous noise-free transmission of sensitive low level signals such as remote surface potential and the like to the sonde.

Abstract: Disclosed is a system for acoustic noise logging in a production well which includes up-hole components and down-hole components including at least two sonic detectors, the up-hole and down-hole components being linked together by a four-wire interconnecting means. In addition, the down-hole components include at least three additional parameter detectors. These additional parameter detectors may include a temperature detector, a conductivity detector and a location detector. The first of these detectors produces a frequency proportional to, for example, temperature. The second detector frequency modulates the temperature signal, for example, in response to location. The third detector amplitude modulates the signal depending on whether or not a conductivity threshold has been exceeded.The foregoing permits simultaneous monitoring of a plurality of down-hole parameters simultaneously without the necessity for multiplexing and yet employs only a four wire interconnecting means.

Abstract: Data is transmitted through a drill string by means of acoustical energy by transmitting an acoustical signal for a first predetermined interval and ceasing transmission of the signal for a second predetermined interval to represent a first binary state; ceasing transmission of the signal for a third predetermined interval to represent a second binary state; and combining transmission and cessation of transmission of the signal in binary sequences representative of borehole data.

Abstract: Novel acoustic logging tools are disclosed for logging unconsolidated formations. These tools include point force shear wave, and multidirectional compressional wave transmitters. A plurality of receivers with sensitivities matched to these transmitter types are provided for selectively gathering P wave and S wave information. The transmitters and receivers are located, sequenced and gated to ensure that high quality wave data is rapidly and reliably collected.

Abstract: A well-logging method and apparatus in which a fast real time portion of a logging signal is sequentially sampled at discrete times. These sampled segments are stored and then are clocked out of storage over an expanded time period.The rms amplitude portion of the logging signal occurring prior to the compression wave part of the logging signal (the nominal noise level) may be used for AGC regulation of an amplifier which amplifies the time-expanded output.A similar development of an rms value can be used for establishing a threshold level for a peak detector, which level is set slightly higher than such rms value. The first three successive samples greater than the threshold level detected by the detector are presumed to be the first three samples of the compression wave. This presumed compression wave is recorded and convolved against the expanded-time digital form of the logging signal to locate the compression wave in a second received signal and, later, the similarly appearing "shear" wave.

Abstract: The disclosure relates to a method and apparatus for acoustic signal detection, adapted for use in acoustic velocity well logging to measure the difference in transit times of an acoustic signal between a transmitter and two or more receivers. In a preferred embodiment of the present invention two timing measurements of the signal arriving at each of two receivers may be made by activating zero crossing detectors at the arrival of the first negative and first positive half-cycles at each receiver. A transit time is calculated from the zero crossing times following the first negative half-cycle.

Abstract: A predetermined signal is removed from waveforms generated in an acoustic investigation of a borehole to enable the accurate detection of relatively weak formation signals. A plurality of waveforms are produced from different sonic receivers used in an acoustic investigation of an earth formation from inside casing set in a borehole. The waveforms include a casing signal which is representative of the acoustic casing wave which traveled from a transmitter through the casing to the receivers. The casing signal is removed by aligning the waveforms in accordance with the known travel times for the casing wave from the transmitter to the receivers and summing the waveforms to produce a casing signal emphasized waveform. A portion of the latter is then subtracted from the waveforms from which the casing signal is thus effectively filtered to facilitate detection and analysis of formation signals present in the waveforms.

Abstract: At least four waveforms representative of sonic waves obtained from an acoustic investigation of a borehole with at least four sonic receivers are combined to automatically measure a parameter of a wave present in the waveforms. The waveforms are derived from sonic receivers which are selectively spaced from each other as well as the sonic transmitter whose sonic pulses caused the sonic waves. Several techniques are described to measure acoustic wave parameters such as the interval travel time of compressional and shear waves for open or cased boreholes. In accordance with one technique a multiple fold correlation process and apparatus are described to measure the acoustic wave parameter.

Abstract: In order to prevent late arriving and higher amplitude shear waves from saturating the subsurface amplifier, the amplitude of each succeeding positive half cycle of the earlier arriving compressional wave is measured and a negative feedback is supplied to the amplifier if the measured amplitude exceeds 50% of full scale. Circuitry is provided for utilization of a two transmitter, two receiver system using the same type of negative feedback to control the gain of the subsurface amplifier.

Abstract: A data telemetry system for use in a plugged exploratory borehole to transmit measurements of subsurface conditions after long delays by use of seismic waves. The system includes a sensor for detecting a downhole condition, such as temperature, and converting it to electrical signals, a timer, and a series of explosive charges. The timer detonates a first of the charges at a preselected time delay and a second charge at a further time delay corresponding to the electrical output of the sensor. The seismic waves generated by the explosions are detected by a seismometer on the earth's surface near the exploratory borehole.

Abstract: Apparatus for correcting measurement errors due to cycle skipping in acoustic-wave transit time measurements.The measurement made during sequence N-1 is stored in an auxiliary memory and compared with the next measurement (sequence N). If the difference between the two successive measurements is smaller than a given fraction of the average period of the acoustic waves used, the measurement of sequence N is transmitted to a measurement memory and recorded. Otherwise, it is the last measurement considered good which is recorded. Moreover, in case of erroneous measurement, the transfer of the control signal for the gain applied to the reception signal is stopped and the gain remains at its former value.Significant improvement in the quality of acoustic well-logging recordings is achieved.

Abstract: In the particular embodiments described, a telemetering system for well logging receives and temporarily stores binary-coded parallel data in a downhole memory unit and continuously interrogates and transmits the stored data to the surface at fixed rate in binary-coded serial format. The system thus accommodates high instantaneous data-generation rates, such as are encountered, for example, in gamma ray spectroscopy tools, without loss of information on the cable. The stored data is compacted, by suppressing leading zeros in data words, prior to application to the cable. This affords faster memory read-out and reduces cable transmission time. The data word format and signal format utilized on the cable provide low error-rate data flow to the surface, as well as facilitating the maintenance of synchronous operation between downhole and uphole functions.

Abstract: A pulse of ultrasonic acoustic energy applied to an earth formation by means of a well logging tool initiates a first compressional formation pulse followed by a secondary pulse of lower amplitude and velocity traveling exclusively in the formation fluid. These two pulses are located, identified and quantized with cross-correlation techniques to give a direct indication of formation permeability, to identify accurately the nature of the formation fluid, and to provide a more accurate determination of formation porosity.