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WO2022011294A1 - Appareil de diagraphie et son procédé d'utilisation - Google Patents

Appareil de diagraphie et son procédé d'utilisation Download PDF

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Publication number
WO2022011294A1
WO2022011294A1 PCT/US2021/041150 US2021041150W WO2022011294A1 WO 2022011294 A1 WO2022011294 A1 WO 2022011294A1 US 2021041150 W US2021041150 W US 2021041150W WO 2022011294 A1 WO2022011294 A1 WO 2022011294A1
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WO
WIPO (PCT)
Prior art keywords
casing
logger
processor
array
logging apparatus
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Ceased
Application number
PCT/US2021/041150
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English (en)
Inventor
Rallis KOURKOULIS
Fani GELAGOTI
Laslo Olah
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Texas Institute of Science Inc
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Texas Institute of Science Inc
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Publication of WO2022011294A1 publication Critical patent/WO2022011294A1/fr
Anticipated expiration legal-status Critical
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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00—Survey of boreholes or wells
    • E21B47/005—Monitoring or checking of cementation quality or level

Definitions

  • This invention relates, in general, to downhole surveying systems and techniques and, in particular, to a logging apparatus and method for use of same for surveying and evaluating downhole environments at oil and gas reservoirs, including wellbores and casings as well as cemented annular spaces therebetween.
  • CBL/VDL Cement-Bond and Variable-Density Logs
  • the ultrasonic pulse-echo method was further developed in the mid 2000 ’s complemented by a pitch-catch configuration that uses an angled transmitter to generate a flexural, known as A0 pseudo Lamb, wave to reverberate in the casing.
  • the attenuation rate of this wave is a function of the annulus acoustic impedance.
  • Combining pulse-echo and pitch-catch measurements provides information on both the compressional and the flexural response of the casing. This allows closer estimate of the casing geometry and the characteristics of the annular fill.
  • the pitch-catch methodology enables measurement of the echo reflected at the interface separating the annulus from the bedrock formation, commonly referred to as third-interface echo or TIE. Analysis of this signal extracts an image of the cement-to-bedrock bonding conditions also providing information on the casing position with respect to the borehole (eccentricity).
  • a logging apparatus and method for use of same that would improve upon existing limitations in functionality. It would also be desirable to enable a mechanical and computer-based solution that would provide enhanced visibility and evaluation across different producing wells. Further, it is desirable to increase functionality with aspects of logging, including detecting defects such as air/mud bubbles or air/mud channels, that are enclosed within the cement body. To better address one or more of these concerns, a logging apparatus and method for use of the same are disclosed. In one aspect, in some embodiments of the logging apparatus, a logger and a measuring unit superposed to the logger may be placed within a casing.
  • the logger includes an array of non- acoustically coupled point-source transducers that may transmit a triggering signal, which is a polarized narrow-band acceleration signal.
  • the array of non-acoustically coupled point- source transducers may receive acceleration signals perpendicular and parallel to a surface of the casing and proximate the logging apparatus.
  • the measuring unit includes an array of acceleration receivers positioned therearound to receiver acceleration signals perpendicular to the casing.
  • a method is provided for determining mechanical properties of a casing-cement bonding material by utilizing a logging apparatus of the type presented hereinabove. The method may induce So Lamb waves in the casing and measure the first arrival of the Lamb waves at the logging apparatus.
  • the method exploits (i) the generation of a stable S o mode (compared to other competitive techniques); and (ii) the increased number of readings to enhance the accuracy of the interpretation in distinguishing: • casing bonded with a lightweight cement from a casing surrounded with a fluid micro annulus; and
  • a micro-annulus gas-filled or liquid-filled from a casing surrounded with a material of low-shear bondage (e.g., cracked cement).
  • This methodology may also be utilized to determine cement presence even when there is a thin cement sheath (> .04”;0.1 cm) and may distinguish lead from tail cement.
  • the method distinguishes between a liquid-filled microannulus from free-casing conditions.
  • a method for reconstructing the theoretical reverberations of a casing having a diameter and thickness disposed within a cement having an acoustic impedance (pVp).
  • This methodology differentiates a “healthy- cement signal,” from a measured response of the respective free-casing.
  • the “healthy-cement signal” is subtracted in the time-domain from data received at the logging apparatus to produce a waveform of non-contaminated casing reverberations that contain information on the position, size, and fill material of the defects enclosed within the cement, including a cement sheath and the like.
  • a method for locating defects covering portion of the wellbore (e.g., within the cement body) by monitoring the uncontaminated reverberations of the casing received at the logging apparatus (e.g., at a particular number of ultrasonic transmitters -receivers) using a previously discussed methodolgy.
  • the method detects gas channels ( ⁇ 1” or 2.54 cm in diameter), mud channels and low-side mud solids that cover portions of the annulus and locates mud filter cakes or mud channels of width less than 0.5” (1.27 cm) at the cement/formation interface.
  • the present disclosure provides an apparatus suitable to perform the abovementioned operations/measurements.
  • Figure 1 is a schematic illustration depicting one embodiment of an onshore hydrocarbon production operation employing a logging apparatus, according to the teachings presented herein;
  • Figure 2 is a schematic illustration depicting one embodiment of the onshore hydrocarbon production operation of figure 1 utilizing the logging apparatus for a logging operation;
  • Figure 3 is a schematic illustration depicting one embodiment of the onshore hydrocarbon production operation of figure 2 in additional detail;
  • FIG. 4 is a functional block diagram depicting one embodiment of the logging apparatus, according to the teachings presented herein;
  • Figure 5 is graphical representation of exemplary acceleration recordings at a periphery of a casing forming a portion of the onshore hydrocarbon production operation
  • Figure 6 is a pictorial graphical representation of exemplary line-source impact and point-source impact signalization
  • Figure 7A is a pictorial representation of one embodiment of a log produced by the logging apparatus and method for use of the same;
  • Figure 7B is a pictorial representation of another embodiment of a log produced by the logging apparatus and method for use of the same;
  • Figure 7C is a pictorial representation of a further embodiment of a log produced by the logging apparatus and method for use of the same;
  • Figure 8 is a pictorial representation of one embodiment of a scanning procedure by the logging apparatus
  • Figure 9 is a flowchart depicting one embodiment of the scanning procedure by the logging apparatus.
  • Figure 10 is a graph of one embodiment of an So mode with measurements along a measuring unit versus decibels;
  • Figure 11 is a graph of another embodiment of an So mode with measurements along a measuring unit versus decibels
  • Figure 12 is a further embodiment of an So mode with measurements along a measuring unit versus decibels
  • Figure 13 is a still further embodiment of an So mode with measurements along a measuring unit versus decibels
  • Figure 14 is a series of graphs showing different aspects of an exemplary acceleration recording
  • Figure 15 is a pictorial flowchart depicting one embodiment of sequence of mathematically -based signal modifications utilized in logging;
  • Figure 16 is a graphical presentation of one embodiment of an initial error
  • Figure 17 is a graphical presentation of one embodiment of the error shown in figure 16 following reconstruction;
  • Figure 18 is a pictorial flowchart depicting one embodiment of an interpretation process utilized in logging;
  • Figure 19 is a pictorial presentation of an exemplary recording utilized in logging
  • Figure 20 is a pictorial presentation of location correlations utilized in logging
  • Figure 21 is a graphical presentation of one embodiment of de-amplification echos encountered during logging
  • Figure 22 is a pictorial presentation of the de-amplification echoes depicted in figure
  • Figure 23 is a pictorial presentation of one embodiment of de- amplification ratios encountered during logging
  • Figure 24 is a graph of one embodiment of a defect width versus an amplitude-based expression
  • Figure 25 is a graph of one embodiment of defect location versus an echo amplitude based expression.
  • FIG 1 figure 1, figure 2, and figure 3, therein is depicted one embodiment of a logging apparatus 10 being employed in an onshore hydrocarbon production operation 12, which may be producing oil, gas, or a combination thereof, for example.
  • a wellhead 14 is positioned over a subterranean hydrocarbon formation 16, which is located below a surface 18.
  • a wellbore 20 extends through the various earth strata including the subterranean hydrocarbon formation 16.
  • a casing string 24 lines the wellbore 20 and the casing string 24 is cemented into place with cement 26.
  • Various surface equipment 36 is located at the surface 18.
  • the logging apparatus 10 is coupled to a lower end 40 of a composite coiled tubing 34.
  • the casing string 24, which may be referred to as the casing includes a surface 50 and a casing axis X. Distal to the surface 50, a casing-cement zone 52 traversing the casing string 24 and the cement 26 is present.
  • the logging apparatus 10 may be incorporated into a downhole tool 60 connected to the lower end 40 of the composite coiled tubing 34 and, more particularly, the logging apparatus 10 includes a moving unit 62, a spinning unit 64 having radially oriented linkages 66, 68 securing a logger 70, a housing 72, and a measuring unit 74 superposed to the logger 70.
  • the housing 72 may be positioned at the measuring unit 74, which may be cylindrical in shape.
  • the moving unit 62, the radially oriented linkages 66, 68, the logger 70, the housing 72, and the measuring unit 74 are configured for placement within the casing string 24. It should be appreciated that although one particular configuration of the downhole tool 60 is presented, other configurations are within the teachings presented herein and the choice of configuration will depend on various specific factors related to the logging and formation.
  • the moving unit 62 positions the logging apparatus 10 within the casing string 24, as shown by arrows U, N, and, in some implementations, the moving unit 62 positions the logging apparatus 10 against the surface 50.
  • the moving unit 62 also repositions the logging apparatus 10 within the casing string 24 as an assigned portion of the casing string 24 is logged.
  • the spinning unit 64 may include an upper rotational member 76 and a lower rotational member 78 with an axial body 80 positioned therebetween.
  • the spinning unit 64 depending on the configuration of the downhole tool 60, rotates the logger 70 as shown by arrow R. Further, as shown, the logger 70 is positioned for radial movement L by the radially oriented linkages 66, 68.
  • the logger 70 includes a counterweight 82 that is positioned opposite of the linkages 66, 68 and serves as a ballast.
  • the rotational positioning provided by the spinning unit 64 as shown by arrow R ensures 360 degree coverage about the casing axis X.
  • the radially oriented linkages 66, 68 provide an adjustable structure 84 that may expand or contract radially, as required, such that the logger 70 is within the casing string 24 and, in some implementations, against the surface 50 of the casing string 24.
  • the housing 72 includes various electronics, which will be described in further detail in figure 4.
  • the measuring unit 74 may be cylindrical in shape exposing a circular face 86 to the surface 50 of the casing string 24. As shown, the measuring unit 74 is superposed to the logger 70 and the spinning unit 64.
  • the logger 70 includes an array of non- acoustically coupled point-source transducers 90, which may transmit a triggering signal T.
  • the triggering signal T may be a polarized narrow-band acceleration signal.
  • the array of non-acoustically coupled point-source transducers 90 may receive acceleration signals Ai perpendicular to a surface 50 of the casing 24 and proximate the logging apparatus 10.
  • the array of non-acoustically coupled point-source transducers 100 may also receive acceleration signals A2 parallel to the surface 50 of the casing 24 and proximate the logging apparatus 10.
  • the acceleration signals Ai, A2 originate from the triggering signals T generated by the logger 70.
  • the measuring unit 74 may include an array of acceleration receivers 102 positioned therearound and, in the illustrated embodiment, on the circular face 86 of the measuring unit 74.
  • the array of acceleration receivers 102 may receive acceleration signals A3 perpendicular to the casing axis X from the casing-cement zone 52. It should be appreciated that acceleration signals Ai, A2, A3 may be at least partially the same acceleration signal.
  • the logging apparatus 10 adheres to the surface 50 of the casing string 24 and transmits triggering signals T which are acceleration waves at a central frequency f 0 (80-120 KHz).
  • the induced waves are standard bulk waves and Lamb waves.
  • Bulk waves (P-waves) travel through the casing 50 into the casing-cement zone 52, which may include a cement sheath, and upon encountering an obstacle (e.g., an interface separating two materials with different acoustic impedances) - be it an air channel, a mud leftover or the formation boundary - a reflection occurs, which may include the aforementioned acceleration signals Ai, A2, A3.
  • an obstacle e.g., an interface separating two materials with different acoustic impedances
  • This reflection of waves is responsible for echoes that are monitored by the logging apparatus 10. This is followed by standard signal processing procedures to detect components of interest in the measured echoes (e.g., arrival time, characteristic peak acceleration, and the like) that can be paired to characteristic properties of a defect (e.g., location, size, fill material, and the like) through a set of mathematical expressions.
  • One key advantage of the present design is a line source impact instead of the commonly applied point source, which introduces a cylindrically symmetric wave field that is easier to interpret by permitting use of simple geometric expressions.
  • the cylindrically symmetric wave field is also characterized by reduced geometric attenuation which invariably increases the accuracy of the measurements.
  • An additional advantage also introduced by a linear configuration of the impact source is the generation of a consistent guided wavefield characterized by: (i) a low amplitude symmetric Lamb wave mode (S), referred to as an extensional or dilatational wave, that primarily advances along the vertical axis of the casing, generating opposite travelling second-order reverberations, which constructively interfere into a fast-travelling intensified dilatational wave; and (ii) a zero-order asymmetric mode (A 0 ) that primarily propagates around the casing circumference.
  • S low amplitude symmetric Lamb wave mode
  • a 0 zero-order asymmetric mode
  • the logging apparatus 10 detects discontinuities D in the casing string 24 and proximate thereto.
  • the logging apparatus 10 adheres to the surface 50 of the casing string 24 and transmits triggering signals T as it traverses a distance through the casing string 24 under the power of the moving units 62, 74.
  • the spinning unit 64 ensures 360 degree coverage within the casing string 24.
  • the logging apparatus 10 combines two modes of operation, a near- field mode of operation and a far- field mode of operation. In general, the near- field mode of operation provides a more thorough screening of a much smaller area. Such detection may be near the surface 50 of the casing string 24 to detect discontinuities D, such as air-cracks, air bubbles, and mud-channels, for example.
  • the far-field mode of operation provides a quick recognition of casing-cement contact conditions that may be a result of the discontinuities D.
  • the array of acceleration receivers 92 receives acceleration signals like A3 in response to triggering signals T transmitted by the logger 70.
  • the logging apparatus 10 evaluates the acceleration signals and if the acceleration signals include an absence of discontinuities D, then in a near-field mode of operation, the array of non-acoustically coupled point-source transducers 90 receive acceleration signals A in response to further triggering signals T.
  • the acceleration signals are reflections or wave reflections of the triggering signals T.
  • the logging apparatus 10 evaluates the acceleration signals.
  • a log is then generated as will be presented in figure 7A through 1C.
  • the log may show via a graphical user interface a computer representation of the casing string 24 and the cement 26 with discontinuities D, such as air bubbles, trapped mud, or a rock formation, shown visually.
  • the logging apparatus 10 utilizes the logger 70 to apply an input force to the casing string 24 in the form of a force time history and near-field acceleration receiving associated with the logger 70 and the far-field acceleration receiving associated with the measuring unit 74 record the produced accelerations on various points along the casing string 24.
  • the logging apparatus 10 is able to distinguish discontinuities D.
  • the logging apparatus 10 may compare an ideal acceleration time history, such as an expected acceleration time history at each point along the casing string 24 under ideal conditions with no discontinuities D with the recorded data gathered by one or more of the near-field acceleration receivers 82 and the far-field acceleration receivers 84. Depending on the discrepancies between the actual and ideal signals, the logging apparatus 10 detects the existence of a discontinuity, including its position, inclination and material. The logging apparatus 10 may provide a solution to the forward problem presented by executing a pattern match approach.
  • an ideal acceleration time history such as an expected acceleration time history at each point along the casing string 24 under ideal conditions with no discontinuities D with the recorded data gathered by one or more of the near-field acceleration receivers 82 and the far-field acceleration receivers 84.
  • the logging apparatus 10 detects the existence of a discontinuity, including its position, inclination and material.
  • the logging apparatus 10 may provide a solution to the forward problem presented by executing a pattern match approach.
  • A* re f the maximum theoretical echo that can be produced by a ring air-channel encircling the casing at a radial distance x re f
  • a d i ff a waveform representing the difference of the correct ‘healthy-cement signal’ (determined by 3D FE analysis) to the mathematically reconstructed ‘healthy-cement signal’
  • AR2 the echo de-amplification factor expressed as a function the defect width
  • N the number of transducers (actuators and receivers) on the Logger NT the number of samplings
  • Vs shear wave velocity of the disposed cement V s V s , d shear velocity of the fill material of an arbitrary defect w the width of a defect enclosed within the cement sheath (be it an air channel, a mud channel or a mud cake) yi the datum point of the Logger center (during the second round of peripheral scans) y a the datum point of the bottom boundary of the CMU when the Logger is centered around the ybot the datum point of the bottom boundary of an arbitrary defect with respect to the Logger center. y bot the datum point of the top boundary of an arbitrary defect with respect to the Logger center. y max the location of maximum reception (along the Logger) y 0 the datum point of the Logger center (during the first round of peripheral scans)
  • X c the thickness of the steel casing Zr, Zi adjacent zones within the formation
  • q ⁇ an angle representing the angular position of the Logger at any given vertical datum.
  • q o an angle describing the starting position of the Logger at any given vertical datum x the mean radiation damping used in 3D FE simulations (assumed common for all materials)
  • p d Vp the acoustic impedance of the fill material of an arbitrary defect
  • pVp the acoustic impedance of the disposed cement f the inclination of an arbitrary defect with respect to the vertical
  • the logger 70 has a length L 0 and, as discussed, the logger 70 is implemented by a number of point-source actuators and sensors working as transmitters and receivers and, in one implementation, embodied as the non-acoustically coupled point-source transducers 90.
  • the logger 70 may be configured to generate polarized narrow-band acceleration signals of a certain duration and frequency and to perform waveform readings utilizing a send and catch function.
  • the non-acoustically coupled point-source transducers 90 which may be transducers are mounted on a pad-type configuration at the logger 70.
  • the logger 70 By activating only the central actuator within the array of transducers, the logger 70 reduces to a point-source logger.
  • the frequency range of the triggering signal is primarily determined by two sets of factors: the signal frequency should be low enough to trigger a limited number of Lamb waves modes on the steel casing as determined, for example, by the thickness; and the diameter of the casing and high enough to ensure that a minimum defect dimension can be detected.
  • the transducers may be piezoelectric devices having a piezoelectric crystal that converts electrical energy into mechanical vibrations to the casing and vice versa. This function is supported by an amplifier hosted at the surface 18.
  • the measuring unit 74 may be a cylindrical measuring unit of approximately 11.8”; 30 cm in length located at a distance above the logger 70 and supporting multiple rows of one-dimensional piezoelectric receivers evenly distributed along the periphery of the measuring unit 74.
  • centralizers within the housing 72 ensure central positioning of the apparatus in the casing.
  • the centralizers may be any type, including, for example, bow spring or leaf spring centralizers can be used.
  • the centralizer mechanism is activated, e.g., a reverse bipolar magnet receiving a current from an amplifier actuates the centralizers, thereby securing the vertical positioning of the apparatus.
  • the centralizer mechanism could be implemented by any other type of an open/close system.
  • the logger 70 While positioned, the logger 70 is expected to perform many peripheral hits per section and this performance is repeated at different altitudes. To do so, the logger 70 may have the ability to perform a 360-degree rotation by the spinning unit 64.
  • the spinning unit 64 may include a stepper motor powered indicatively by batteries or electricity wire that places into motion the axial body 80 acting as a rotary drive shaft on which the logger 70 secured as a pad-type tool is fixed.
  • the counterweight 82 acts as a ballast.
  • the logging apparatus 10 includes a processor 100, memory 102, storage 104, a signal library 106, a moving unit input/output 108, an adjustable structure input/output 110, a spinning unit input/output 112, the logger 70, the measuring unit 74, and a communication input/output 114, which are interconnected by a busing architecture 116 within a mounting architecture.
  • the processor 100 may process instructions for execution within the logging apparatus 10 as a computing device, including instructions stored in the memory 102 or in the storage 104 or in the signal library 106.
  • the memory 102 stores information within the logging apparatus 10 as a computing device.
  • the memory 102 is a volatile memory unit or units.
  • the memory 102 is a non-volatile memory unit or units.
  • the storage 104 provides capacity that is capable of providing mass storage for the logging apparatus 10.
  • the signal library 106 may include a set of offline signal parameters.
  • the offline signal parameters which are also signal parameters measured downhole, may include the length of the discontinuity, the radial distance of the discontinuity from the center of the logging apparatus 10, the inclination angle of the discontinuity, the vertical position of the discontinuity, and mechanical proprieties of the fill material taking into consideration the casing string 24 and the cement 26.
  • the set of offline signal parameters may include a library of built-in charts that may be accessed to perform one-to-one or one-to-many correlations of signal parameters to specify physical and geometric properties of any discontinuities.
  • the signal library 106 and accompanying algorithmic capability may be based on a numerical offline solution of a minimum number of generic forward problems formulated into the content of the signal library 106 that collectively describe a signalized response to any discontinuity.
  • Various inputs and outputs provide connections to and from the logging apparatus 10 as the computing device, wherein the inputs are the signals or data received by the processor 100 and the memory 102, and the outputs are the signals or data sent from the processor 100 and the memory 102.
  • the various inputs and outputs include the moving unit input/output 108, the adjustable structure input/output 110, the spinning unit input/output 112, and the communication input/output 114.
  • the moving unit input/output 108 provides communication with the moving unit 62 and control thereof.
  • the adjustable structure input/output 110 provides communication with the adjustable structure 84 including the radially oriented linkages 66, 68 to radially adjust the logger 70.
  • the spinning unit input/output 112 is provides communication with the spinning unit 64 and control thereof. As previously alluded, the spinning unit 64 ensure a sufficient number of radial hits are completed to ensure modeling in three-dimensions.
  • the communication input/output 114 provides data communication, which may be wired, wireless, or a combination thereof, with the various surface equipment 36. It should be appreciated that the processor 100 and the memory 102 may be located in the housing 72 or distributed between the housing 72 and a surface computing device, which may form a portion of the various surface equipment 36.
  • the memory 102 and the storage 104 are accessible to the processor 100 and include processor-executable instructions that, when executed, cause the processor 100 to execute a series of operations.
  • first processor-executable instructions are provided.
  • the processor 100 is caused to actuate the logger to transmit triggering signals T.
  • the processor 100 is then caused to operate in a far- field mode of operation where the array of far-field acceleration receivers 84 receives acceleration signals in response to the triggering signals T.
  • the acceleration signals are then evaluated by the processor 100 to determine a set of signal parameters.
  • the processor 100 may access the signal library 106 and compare the set of signal parameters to the offline set of signal parameters for a more informed evaluation. Also, in the far-field mode of operation, the processor 100 may calculate the rate of decay of the received acceleration signals A to determine if discontinuities are present.
  • the processor-executable instructions cause the processor 100 to operate in a near- field mode of operation where the array of near-field acceleration receivers 82 receives acceleration signals in response to triggering signals T.
  • the processor 100 is then caused to evaluate the acceleration signals.
  • the processor 100 may execute signal processing on at least a portion of the acceleration signals to extract a set of signal parameters.
  • the signal library 106 may be accessed by the processor 100.
  • the processor 100 compares the set of signal parameters to an offline set of signal parameters in the signal library 106.
  • the processor-executable instructions then cause the processor 100 to generate a log, which may be generated substantially in real-time.
  • the processor-executable instructions cause the processor 100 to signal the spinning units 66, 70 to rotate the logging apparatus 10 about the casing axis X. If 360 degree coverage of the casing axis X is present in the data and the log, for example, then the processor 100 may be caused to signal the moving unit 62 to reposition the logging apparatus 10 within the casing string 24 to continue the logging operation.
  • second processor- executable instructions are provided.
  • the processor 100 is caused to operate in a line source mode of operation including the plurality of triggering signals where the plurality of triggering signals include polarized narrow-band acceleration signals having varying amplitudes, and, alternatively, the processor 100 is caused to operate in a point source mode of operation including a single source where the single source is one of the array of non-acoustically coupled point-source transducers.
  • the processor 100 may also be caused to execute a fast scanning protocol by reading attenuation of acceleration signals received at the measuring unit.
  • the memory 102 may include third processor-executable instructions that, when executed, cause the processor 100 to execute a fast-scanning protocol by reading attenuation of the acceleration signals received at the measuring unit, and execute, responsive to the fast-scanning protocol detecting a slow-scanning condition, a slow-scanning protocol by reading the acceleration signals received at the logger.
  • the slow-scanning condition may be an absence of micro-annulus conditions and gas-filled channel conditions.
  • the memory 102 may include fourth processor-executable instructions that, when executed, cause the processor 100 to induce symmetric modes of Lamb waves into the casing via a line-source impact and induce antisymmetric modes of Lamb waves into the casing via a point-source impact, and evaluate an integrity of the casing.
  • the processor- executable instructions may cause the processor 100 to further monitor, with the measuring unit, attenuated symmetric Lamb waves or, measure attenuation of separate modes of Lamb waves.
  • the processor 100 may then be caused to identify a bond defect, the bond defect being selected from the group consisting of an absence of micro-annulus conditions and gas-filled channel conditions.
  • the casing may include a bonding material such as cement, lightweight cement, a thin cement sheath, and a low shear bond material.
  • the memory 102 may include fifth processor-executable instructions that, when executed, cause the processor 100 to induce P waves into the casing, and measure uncontaminated reverberations of the casing via the logger.
  • the processor 100 may then be caused to, at least one of the following: at least partially reconstruct a theoretical reverberation of the casing based on a reference casing, at least partially determine a radial location of a defect by calculating an arrival echo time, or at least partially determine a width of the defect by calculating arrival echo times.
  • the processor 100 may then be caused to at least partially correlate a vertical position of a defect with a recorded characteristic echo, at least partially describe an echo de-amplification function with respect to dimensions of the defect, and at least partially correlate an amplitude of the recorded characteristic echo to a fill material of the defect with respect to the radial location.
  • additional processor-executable instructions when executed may cause the processor 100 to identify a defect.
  • the defect may be from the group consisting of gas/fluid channels located within a cement body proximate the casing, or mud, for example.
  • a log may be generated, including being generated in real-time.
  • the log may be a two- dimensional mapping of a portion of the casing cemented by the cement within the wellbore.
  • the log may be a three-dimensional mapping of a portion of the casing cemented by the cement within the wellbore.
  • processor-executable instructions presented hereinabove include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions.
  • Processor-executable instructions also include program modules that are executed by computers in stand-alone or network environments.
  • program modules include routines, programs, components, data structures, objects, and the functions inherent in the design of special-purpose processors, or the like, that perform particular tasks or implement particular abstract data types.
  • Processor-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the systems and methods disclosed herein.
  • the point source induces both symmetric 94 and anti- symmetric modes 100 travelling at slightly different speeds within the casing, which further perplexes mode detection while increases the uncertainty of the interpretation.
  • Propagation of the Lamb waves is dependent upon density, elasticity, and material properties of the wave medium within which they propagate.
  • the amount of attenuation can depend on how an acoustic wave is polarized and the coupling condition between the casing and the cement.
  • a cemented pipe generally demonstrates higher Lamb-wave mode attenuation than a free pipe.
  • attenuation measurements of S o mode allow for the determination of the integrity of the shear-bond between the casing and the disposed cement. Combining this measurement, with attenuation measurement of the A o mode it is also possible to measure variations in the V p of the bonding material and therefore makes it possible to distinguish fluid-filled microannulus from de-bonded casings.
  • the logging apparatus may produce a log 120 in substantially real-time based as the logging is performed.
  • the log 120 includes a downhole representation 122 and a graphical user interface 124.
  • a meter 126 shows the depth of the logging apparatus where data is being collected. In figure 7A, the depth is 830.4 meters and, in both figures 7B and 7C, the depth is 830 meters.
  • the downhole representation 122 includes a downhole image 128 with an image of the casing string 24i with the cement 26i.
  • various discontinuities 130 which may be air-cracks, air bubbles, mud-channels, and the like, include mud-channel 132 and air- cracks 134, which are shown on the casing string 24i and the cement 26i.
  • a three-dimensional mapping 136 of a portion of the casing cemented by the cement 26i within the wellbore may be enabled.
  • a two-dimensional mapping 138 of a portion of the casing cemented by the cement 26i within the wellbore may be enabled.
  • the graphical user interface 124 includes an alarm notification 140 if a dangerous condition is detected, a monitoring log 142, and a screenshot function 144, by way of example.
  • Logging data 146, a legend 148 which may texturize the downhole image 128, and a depth reading 150 are also included.
  • figures 5B and 5C show the logging operation at 830 meters with additional casing string 24i and cement 26i mapped.
  • Various discontinuities 130 include the mud-channel 132, air-cracks 152, 154, and air bubbles 156. In this manner, the logging apparatus 10 generates the log 120 in real time to survey and evaluate the downhole conditions.
  • the logger is positioned at any given datum y 0 and central angle 0 o .
  • the flowchart for a complete screening, including a fast and slow screening, of a cylindrical slice at altitude y 0 is provided in figure 9 and it should be appreciated by those having skill in the art that a minimum required number of vertical and peripheral scans will need to be selected depending on downhole conditions to ensure zonal isolation.
  • the logger has an initial position at block 180. According to the embodiment of figure 9, two types of measurements are employed. Measurements are made along the measuring unit, which may be located 7.87-11.81” (20-30 cm) above the logger covering a total length of 11.81” (30 cm).
  • the measuring unit includes a number of spaced-apart one-dimensional acoustic receivers that may be vertically aligned in order to measure the first arrivals of Lamb waves (S o or A 0 waves, depending on the source configuration) and estimate a rate of attenuation with travelling distance, which serves a fast- screening test of the bondage integrity to identify free-casing or microannulus conditions, for example.
  • This implementation of this methodology is shown in blocks 182, 184. Thereafter, the logger is repositioned at block 186 and a fast scanning occurs at block 188.
  • Substantially simultaneously a slow scanning occurs at block 190. More particularly, measurements along the logger are collected at the locations of the individual dual-purpose sensors, which act as receivers, of the logger. The exact number of receivers (N) depends on the total length of the logger (L 0 ) and the dimensions and space requirements of the individual receivers.
  • S o Lamb wave attenuation measurements at the measuring unit may be provoked by linear-source impacts, that is upon all the Logger-actuators being simultaneously triggered.
  • This methodology has at least three uses, including (1) distinguishing a casing bonded with a lightweight cement from a casing surrounded with a fluid micro- annulus; (2) determining if cement is present when there is a thin cement sheath; and (3) determining the properties of the bonding material disposed outside of a casing (e.g., differentiating between lead, such as a weaker cement and tail, a stronger cement.
  • figure 10 which includes an attenuation graph 192 that illustrates recorded values of Lamb- wave attenuation as a function of the distance of the receiver from the Logger.
  • the attenuation graph 192 of figure 10 shows the dependence of S o wave attenuation on the shear properties of the bondage material.
  • measurements of the attenuation can be directly related to the bonding properties of the disposed material: high attenuation (of the order of 12.2 dB/ft), which is an indication of healthy cementing, while low shear bonding is manifested by the significantly reduced attenuation values that almost diminish to that of the free casing for Vs ⁇ 300 m/s.
  • high attenuation of the order of 12.2 dB/ft
  • low shear bonding is manifested by the significantly reduced attenuation values that almost diminish to that of the free casing for Vs ⁇ 300 m/s.
  • In the intermediate space lies the line of the lightweight cement for which we read 8.8 dB/ft.
  • Figure 11 provides a similar version with attenuation graph 194, where a presentation of casings covered by different cement sheaths is provided: a thick sheath of 3.93” (10 cm) and a thin sheath of 0.39” (1 cm).
  • a presentation of casings covered by different cement sheaths is provided: a thick sheath of 3.93” (10 cm) and a thin sheath of 0.39” (1 cm).
  • the thickness of the cement has no measurable effect on the attenuation values confirming that the method of this embodiment can be also efficient in cases of thin sheaths (being the result of improper centralization during installation).
  • the S o attenuation of the fluid micro annulus is identical to that of the free-casing denoting that the So measurement alone is not enough to distinguish between materials of different acoustic impedances (e.g. , water and air)
  • the method is complemented by A 0 attenuation readings as explained herein.
  • the lines although not entirely smooth, display different inclinations; the water microannulus is responsible for higher attenuation rates (in the order of 30 dB/ft) compared to the free-casing (15 dB/ft).
  • a method to retrieve the un contaminated echoed signal generated, for example, at potential obstacle interfaces and reflected back to the receivers, from the actually recorded signal by the measuring unit is a combination of two superimposed signals: (a) the “theoretical” recording assuming zero echoes from obstacles (or other interfaces) and (b) the echoed signal. Therefore, the problem reduces to simply reconstructing the “theoretical signal” corresponding to a “non-defective” instance of the casing-wellbore and subtract it in the time-domain from the recording. The resulting echoed signal will be subsequently fed into the interpretation method described by the fourth aspect of this embodiment to allow detection of specific defects and their properties.
  • the process is backed up by the following elements: (1) the amplitude and the phase of the theoretical signal is a function of the acoustic impedance of the contact material, and it is not affected by the thickness of the cement sheath. (2) It is mathematically possible to invent a two-parameter mathematical function to describe the transformation from the free-casing to the bonded casing in the frequency domain; (3) the parameters of the transformation function vary linearly with the acoustic impedance of the bonded material.
  • Step (1) at block 208 assuming that the acoustic impedance is known, the transformation functions for the real and imaginary part of the signal are defined.
  • Step (2) at block 210 the free-casing signal is retrieved from a benchmarking hit, which occurred before the casing installation, and transformed in the frequency domain.
  • Step (3) shown in block 212 by combining Steps (1) and (2) the theoretical “healthy-cement signal” is determined that corresponds to the specific impedance property.
  • Step (4) at block 214 the echoed signal is determined by subtracting the “healthy-cement signal” from the respective recording.
  • a method to detect defects of any type entrapped within the cement sheath is practiced.
  • This embodiment of the methodology analyzes in time and frequency domains the echoed signals.
  • the method may detect: gas channels ( ⁇ 1”; 2.54 cm in diameter); mud channels and low-side mud solids that cover portions of the annulus; mud filter cakes; or mud channels of width ⁇ 0.5”; 1.27 cm located at the cement/formation interface, for example.
  • Figure 18 is a flowchart illustrating a portion of this methodology of determining the location and the properties of defects.
  • the interpretation initiates when the tool has completed a full scanning of the periphery and A * x , A * y acceleration time histories (uncleared signals) have been stored in a [N x NT x No] matrix (as explained above).
  • the method is divided into two consecutive parts; namely, blocks 230, 232, 234, 236, 238 trace the projection of the defect on a horizontal cross section of the wellbore at the level of the center of the logger and then outline the boundary of the defects.
  • the method stores the Ax acceleration measurements of the center of the logger at all No measuring positions of the periphery prior to estimating the theoretical “healthy cement signal” at block 232.
  • recordings are translated to “uncontaminated” echoed signals.
  • the arrival time (tar) of the first echo is estimated (representing the initiation of refractions) and based on that the location of the firstly encountered interface is approximated.
  • the t ar equals the time required for the heading front of the input radial location x 0 of the defect according to: where xc, V P steel , V P cement are known properties.
  • the x 0 calculations over the No measuring positions are graphically represented to produce polar plots.
  • a geometric algorithm is introduced to categorize the polar points as “Possible Defect” or “Possible Boundary” based on geometric criteria. Then, the points that are flagged as “Possible Boundary” are subjected to a second-round screening to distinguish by means of a wavelet analysis, for example, between normal boundary conditions that require no further treatment and defective conditions (e.g. , mud leftovers or de-bonding) at the rear boundary of the cement.
  • All defective conditions are then subject to a more detailed interpretation during which the specifics of the defect will be determined by utilizing an algorithm that uses acceleration measurements recorded during the most relevant measuring position (e.g., the position that is closer to the center of the defect width - output of Part-A algorithm).
  • All N recordings along the logger surface (in both directions (A x , A y ) are used.
  • This methodology employs basic signal processing procedures to identify the characteristic acceleration peak (A x,0 ), the location of maximum peak recording (L o /2 ⁇ y max ⁇ -L 2, the characteristic time-lag along the N receivers of the logger and the characteristic A x,max /A y,max ratio recorded at the location of maximum response (y max ).
  • “high-offset” defects invariably generate maximum echoes at y m , u 1 y 0 .
  • the 3D FE analyses on defects of varying x 0 , thickness t and fill material demonstrate that the location of y max is a linear function of the vertical coordinate of the nearby vertical boundary of the defect (y bot or y u , p) .
  • y max known, it is possible to vertically position the defects with respect to the logger center (y 0 ).
  • and [ARi-L] expressions derived from axisymmetric defects are used to correlate the characteristic acceleration peak (A x,0 ) of the defect to its effective length, which is the projected contact length of the defect and the Logger) for a given x 0 and fill material 0 ° d V p,d ).
  • a x,0 characteristic acceleration peak
  • the theoretical maximum echo is developed when the defect is located centrally to the logger 70.
  • the A x, o decreases with increasing offset generating a characteristic bell-shape pattern.
  • the FE 3D analyses confirm that the attenuation ratio (AR) defined as the recorded echo to the theoretical maximum echo A x o that would have been recorded if the defect was centrally aligned to the Logger is solely controlled by the vertical offset of the defect and thus by its effective length. That is, the the theoretical maximum echo A x o is not affected by the x 0 , the thickness (t a or t d ), the length L and the fill material p d V p,d of the defect.
  • AR attenuation ratio
  • the characteristic acceleration peak (A x,0 ) is unaffected by the defect length provided that the defect exceeds a specific length limit (e.g., L> 3cm).
  • a specific length limit e.g., L> 3cm
  • the [ dimA * X 0 - x 0 ] expression is pertinent to nearly vertical defects (Q ⁇ 10°) and relates the dimensionless amplitude of the theoretically maximum recorded echo A x o (divided by the theoretical maximum echo A r f e ⁇ of a vertical air channel located at a reference radial distance x ref ) to the radial distance x 0 of the defect.

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  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Fluid Mechanics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geophysics (AREA)
  • Quality & Reliability (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

La présente invention concerne un appareil de diagraphie (10) et son procédé d'utilisation. Selon un mode de réalisation de l'appareil de diagraphie (10), un enregistreur (70) et une unité de mesure (74) superposée à l'enregistreur (70) peuvent être placés à l'intérieur d'un boîtier (24). L'enregistreur (70) comprend un réseau de transducteurs de source ponctuelle couplés de manière non acoustique (90) qui peuvent transmettre un signal de déclenchement (T), qui est un signal d'accélération à bande étroite polarisé. Le réseau de transducteurs de source ponctuelle (90) à couplage non acoustique peut recevoir des signaux d'accélération (A1, A2) perpendiculaires et parallèles à une surface (50) du boîtier (24) et à proximité de l'appareil de diagraphie (10). L'unité de mesure (74) comprend un réseau de récepteurs d'accélération (102) dont les récepteurs sont positionnés autour de cette dernière pour recevoir les signaux d'accélération (A1) perpendiculaires au boîtier (24).
PCT/US2021/041150 2020-07-09 2021-07-09 Appareil de diagraphie et son procédé d'utilisation Ceased WO2022011294A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114941521A (zh) * 2022-06-16 2022-08-26 中海油田服务股份有限公司 一种超声波测井方法、装置及设备

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US20040216873A1 (en) * 2003-02-18 2004-11-04 Baker Hughes Incorporated Radially adjustable downhole devices & methods for same
US20060198243A1 (en) * 2005-03-02 2006-09-07 Baker Hughes Incorporated Use of lamb waves in cement bond logging
US20070280048A1 (en) * 2006-06-06 2007-12-06 Baker Hughes Incorporated P-wave anisotropy evaluation by measuring acoustic impedance of the rock by beam-steering from within the borehole at different angles
US20120120764A1 (en) * 2010-11-12 2012-05-17 Los Alamos National Security System and method for investigating sub-surface features and 3d imaging of non-linear property, compressional velocity vp, shear velocity vs and velocity ratio vp/vs of a rock formation
US20200033494A1 (en) * 2018-07-27 2020-01-30 Baker Hughes, a GE compnay, LLC Through tubing cement evaluation using seismic methods

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040216873A1 (en) * 2003-02-18 2004-11-04 Baker Hughes Incorporated Radially adjustable downhole devices & methods for same
US20060198243A1 (en) * 2005-03-02 2006-09-07 Baker Hughes Incorporated Use of lamb waves in cement bond logging
US20070280048A1 (en) * 2006-06-06 2007-12-06 Baker Hughes Incorporated P-wave anisotropy evaluation by measuring acoustic impedance of the rock by beam-steering from within the borehole at different angles
US20120120764A1 (en) * 2010-11-12 2012-05-17 Los Alamos National Security System and method for investigating sub-surface features and 3d imaging of non-linear property, compressional velocity vp, shear velocity vs and velocity ratio vp/vs of a rock formation
US20200033494A1 (en) * 2018-07-27 2020-01-30 Baker Hughes, a GE compnay, LLC Through tubing cement evaluation using seismic methods

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114941521A (zh) * 2022-06-16 2022-08-26 中海油田服务股份有限公司 一种超声波测井方法、装置及设备

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