Schlumberger Technology Corporation

Mikhail Lemarenko

Christoph Klieber

Sylvain Thierry

Sandip Bose

Smaine Zeroug

Josselin Kherroubi

Ralph Michael D'Angelo

Ram Sunder Kalyanraman

Thilo Michael Brill

Jean-Luc Le Calvez

Kenneth William Winkler

Elizaveta Rybka

Systems and methods for identifying a potential third interface echo (TIE) using objective criteria are provided. A system includes an acoustic logging tool that obtains measurements in a wellbore and a data processing system that has a processor that receives the measurements from the acoustic logging tool. The data processing system may identify a third interface echo (TIE) using a neural network and/or by a signal analysis method based on the behavioral characteristics of the TIE signal.

Third interface echo (TIE) detection from flexural data for gas/liquid annulus discrimination

Acoustic imaging waveforms are measured utilizing a downhole acoustic tool within a wellbore, and then aligned relative to a main echo of each waveform. The aligned waveforms are then subjected to a first low-pass filter. Residuals are extracted by determining differences between the aligned waveforms and the filtered waveforms. The residuals are aligned to corresponding acoustic firing pulses of the downhole acoustic tool. The aligned residuals are subjected to a second low-pass filter. The measured waveforms are aligned to the corresponding acoustic firing pulses. Noise associated with the downhole acoustic tool is removed from the pulse-aligned, measured waveforms utilizing the filtered residuals.

Coherent noise reduction in ultrasonic data

Techniques involve obtaining acoustic data (including waves reflected from the casing, the annular fill material, the formation, and/or interfaces between any of the mud, the casing, and the annular fill material) from an acoustic logging tool. Techniques include normalizing the acoustic wave to result in a normalized wave having a comparable spectral shape with a reference wave, and comparing the normalized wave with the reference wave. The reference wave may be generated or modeled or produced from a look-up table or database, and may be estimated based on initial estimates of wellbore parameters. Based on the comparison of the normalized wave with the reference wave, a best-fit reference wave substantially matching the normalized wave may be identified. The best-fit reference wave may correspond with a thickness of the casing, an acoustic impedance of the annular fill material, and an acoustic impedance of mud.

Resonance-based inversion of acoustic impedance of annulus behind casing

A method of determining properties of a wellbore in a formation includes obtaining from the acoustic logging tool, acoustic data comprising an acoustic wave reflected from the casing, the annular fill material, one or more interfaces between any of the mud, the casing, and the annular fill material, or combinations thereof. The method includes normalizing the acoustic wave in a frequency domain, resulting in a specular spectrum and removing spectral noise outside a region of interest in the specular spectrum. The method includes shaping the specular spectrum around a resonance frequency, converting the shaped specular spectrum into a time domain, resulting in a renormalized waveform, and subtracting from the renormalized waveform one or more of a specular noise, second interface echoes, resulting in a third interface echo signal.

Techniques for removing interface noise from acoustic log data

Methods and systems for identifying and locating fractures within a wellbore are described herein. One such method includes generating an acoustic wave. At least a first portion of the acoustic wave travels along a wall of the wellbore. The first portion of the acoustic wave interacts with a feature on the wall of the wellbore, such as a fracture, and generates a second acoustic wave. The second acoustic wave is detected to obtain acoustic data. A chevron pattern is identified within the acoustic data and a location for the feature is determined using the identified chevron pattern.

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Clamart, France

Mikhail Lemarenko