Baker Hughes Corporation

Baker Hughes, a Ge Compnay, LLC

Alexei Bolshakov

Douglas J Patterson

Vladimir Dubinsky

Xiao Ming Tang

Joseph Gregory Barolak

Edward Domangue

James V Leggett, Iii

Vladimir Nikolaevich Belov

Victor Yushin

Sergey Egerev

Xiao-Ming Tang

Victor Tiutekin

Tsili Wang

Volker Krueger

Dimitri M Donskoy

Pushkar N Jogi

George A Alers

Ron Alers

Zarema Dubinsky

Dimitri Donskoy

Joseph G Barolak

A method of determining properties of a bonding material disposed outside of a casing in a borehole includes at least two of the following three pairs of operations: (1) inducing an acoustic wave in the casing, and measuring attenuation of the acoustic wave, by pulse-echo or other cement bond logging measurement; (2) inducing an SH wave in the casing, and measuring attenuation of the SH wave; and (3) inducing a Lamb wave in the casing, and measuring attenuation of the Lamb wave. (2) and/or (3) may be performed by an electromagnetic acoustic transducer. The method further includes determining the shear velocity or shear impedance and the compressional velocity or compressional impedance of the bonding material based on appropriate ones of the measurements. The bonding material may be cement.

Use of Lamb and SH attenuations to estimate cement Vp and Vs in cased borehole

Disclosed is a method implemented by a processor for imaging a formation penetrated by a borehole. The method includes: obtaining acoustic data in a depth-time domain using an acoustic downhole tool disposed at a depth in the borehole, the acoustic downhole tool having an acoustic source and an acoustic receiver; transforming the acoustic data in the depth-time domain into a Radon domain using a Radon transform; filtering the acoustic data in the Radon domain to increase a signal of interest in the acoustic data in the Radon domain; determining a location of a point in the formation that reflected acoustic energy emitted from the acoustic source to the acoustic receiver, the location of the point being represented in the Radon domain; and inverting the location of the point represented in the Radon domain into a radius-depth domain to image the formation.

Radon migration of acoustic data

Evaluating casing thickness by inducing SH0 and SH1 modes of a shear wave in the casing. The SH0 group velocity and SH1 mode group velocity (Vg) are measured and the measured SH0 mode group velocity is assigned as the tubular material shear velocity (Vs). A shear wave wavelength &#x3bb; from the ratio of SH0 mode frequency (f) and the measured SH0 group velocity is estimated. The tubular thickness (d) is estimated from the estimated shear wave wavelength &#x3bb;. The transmitter can be calibrated to operate at an optimum frequency.

Casing thickness evaluation method

Passive suppression of casing signals is used to improve the ability to measure formation velocities. Passive suppression includes the use of a magnet slidably coupled to the casing.

Active noise cancellation through the use of magnetic coupling

A method and apparatus for evaluating a bond between a formation and a bonding material. The method includes emitting a shear wave into the tubular, recording the response of the shear wave, and evaluating the response to obtain bond information. The bond information includes bond material thickness and efficacy of the bond between cement and formation. The method includes studying and utilizing the time lag of the direct wave and wave events, as well as the interference of these waves on a spectral graph. A calibration method is included as well.

Cement bond analysis

A method and apparatus useful to determine the integrity of a cement bond log disposed in the annular space between a casing and a wellbore. The method and apparatus produce a transversely polarized shear wave and emit the wave through the casing and into the wellbore. The transversely polarized shear wave attenuates upon passage through the cement bond log. The integrity of the cement bond log can be determined through an analysis and evaluation of the attenuation results.

Method and apparatus for cement evaluation using multiple acoustic wave types

A method useful for evaluating the presence and/or the quality of the cement bond of a downhole tubular. The method involves measuring radial resonance modes of the tubular, and comparing those measured values to the unbound tubular resonant values of a calibration ring. For a well bonded tubular, the measured radial resonance should be greater than that of the unbound tubular calibration ring. In regions where a fluid, such as water surrounds the outside of the tubular, or the cement is otherwise not bonded to the outer surface of the tubular, the measured response should be less than the calibrated response. The calibration ring should have the same diameter, wall thickness, and be made of the same material as the tubular.

Casing resonant radial flexural modes in cement bond evaluation

A method and apparatus useful to determine the integrity of a cement bond log disposed in the annular space between a casing and a wellbore. The method and apparatus induce a Lamb wave in the casing and into the wellbore. The Lamb wave attenuates upon passage through the cement bond log. The integrity of the cement bond log can be determined through an analysis and evaluation of the attenuation results.

Use of Lamb waves in cement bond logging

Passive and active suppression of casing signals is used to improve the ability to measure formation velocities. Passive suppression includes the use of a magnet slidably coupled to the casing. Active suppression uses measurement of casing signals to control the output of an electromechanical acoustic transducer which cancels the propagating signal. Feedback control may be provided.

Method and apparatus for cement bond evaluation using transversely polarized shear waves

A bond log device comprising a sonde, an acoustic transducer, and an acoustic receiver. The acoustic transducer is comprised of a magnet combined with a coil, where the coil is energizable by an electrical current source. The acoustic transducer can also be comprised of an electromagnetic acoustic device. The acoustic transducer is capable of producing various waveforms, including compressional waves, shear waves, transversely polarized shear waves, Rayleigh waves, Lamb waves, and combinations thereof.

Use of electromagnetic acoustic transducers in downhole cement evaluation

A plurality of heavy mass irregularities attached to an inner wall of the drill collar attenuate waves traveling through the collar. The plurality of heavy mass irregularities are spaced and sized for the maximum attenuation of acoustic pulses in a predetermined frequency range. The mass irregularities may be rings secured to the inner surface of the collar by neck pieces, extending outwardly from the outer circumference of the ring. The mass irregularities may be made of steel or tungsten and are between six and ten in number. The spacing of the irregularities may lie between twelve and fourteen centimeters. A center pipe may be included to isolate the irregularities from the fluid flow associated with the drilling operation. The pipe may be of a soft material such as rubber to reduce transfer of acoustic noise along the drill string. The irregularities may be in an oil based fluid with the pipe fitting closely in the center of the rings. In another embodiment of the invention, each of the mass irregularities is attached to the drill collar over substantially the entire length of the mass irregularity, enabling the attenuation of high frequencies. In yet another embodiment of the invention, the attenuator comprises a substantially cylindrical body with a plurality of recesses on the inside and/or outside of the cylindrica body, with the length of the recesses selected to provide attenuation within a specified band. In another embodiment of the invention, the attenuator comprises a plurality of sections each having an inner diameter and an outer diameter, each section acting like a waveguide with an associated passband and reject-band.

Acoustic isolator downhole applications

An apparatus for performing acoustic investigations while drilling a borehole in a subsurface geological formation comprises a longitudinally extending assembly conveyed in the borehole on a drilling tubular. The assembly and the drilling tubular have a drilling fluid flowing through a longitudinally extending passage therein. An acoustic transmitter is supported by the assembly. The transmitter generates acoustic signals in the assembly, the borehole and the subsurface formation. An acoustic receiver is spaced apart from the transmitter and receive the acoustic signals. An attenuator is located in the assembly between the acoustic transmitter and the acoustic receiver for attenuating the acoustic signals in the assembly within a predetermined frequency range. The attenuator comprises a tubular element of a composite material having a substantially cylindrical outer surface. The outer surface has a plurality of spaced apart masses having a predetermined spacing, mass and length firmly attached thereto.

Acoustic isolator for downhole applications

A plurality of heavy mass irregularities attached to an inner wall of the drill collar attenuate waves traveling through the collar. The plurality of heavy mass irregularities are spaced and sized for the maximum attenuation of acoustic pulses in a predetermined frequency range. The mass irregularities may be rings firmly coupled to the outer surface of the collar. Alternatively, the mass irregularities may be rings firmly coupled to the outer collar surface by neck pieces, extending inwardly from the inner circumference of the ring. The mass irregularities may be made of steel or tungsten. In another preferred embodiment, the mass irregularities are asymmetrically coupled to an outer collar wall for providing preferential directional attenuation.

Determination of the rate of penetration (ROP) of drilling has usually been based upon surface measurements and may not be an accurate representation of the actual ROP. This can cause problems in Logging While Drilling (LWD). Because of the lack of a high-speed surface-to-downhole communication while drilling, a conventional method of measuring ROP at the surface does not provide a solution to this problem. However, the instantaneous ROP can be derived downhole with a certain degree of accuracy by utilizing an accelerometer placed in (or near) the tool to measure acceleration in the axial direction. When three-component accelerometers are used, the method may be used to determine the true vertical depth of the borehole.

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Pearland, TX, United States of America

Alexei Bolshakov