A model is used to generate corrections to mitigate ideal condition artifacts in acoustic property values of an annular material in a cased wellbore. A mathematical model that generates acoustic property values at ideal conditions introduces artifacts into the acoustic property values. Acoustic measurements of an annular material are used to generate features that represent wellbore conditions and are not accounted for in the mathematical model that generates acoustic property values. A model will generate corrections for acoustic property values of an annular material with the features to yield a more accurate acoustic property profile for the annular material of a cased hole.

A method for evaluating a sealing material positioned between a casing of a wellbore and a subsurface formation in which the wellbore is formed includes emitting an acoustic waveform outward from a position within the casing and detecting a return waveform that is generated in response to the acoustic waveform interacting with a region of interest that includes at least a portion of the sealing material. The method includes determining a first time window of the return waveform associated with the region of interest and trimming the return waveform based on the first time window. The method further includes determining a first spectral power density for the first time window of the trimmed return waveform and determining a composition ratio for the region of interest based on the first spectral power density.

A method for generating a core description is disclosed. The method includes coring and collecting rock cores from geographical locations in the subterranean formation, detecting, using an augmented reality (AR) device worn by a user, content of an identifying tag of a rock core within a device view of the AR device to identify a well where the rock core is obtained, retrieving, by the AR device from a data repository, historical data of the well, activating, by the AR device, a sensor to acquire additional data from the rock core to supplement the historical data, and presenting, by the AR device, an AR image including a first image of the historical data and the additional data superimposed over a second image of the rock core, where the user generates the core description based on viewing the AR image.

Methods and systems for logging a wellbore having a casing are described. Acoustic energy, typically ultrasonic acoustic energy, is used to stimulate reverberation of the casing at a harmonic (for example, the second or third harmonic) of the resonance frequency of the casing. One or more acoustic sensors are used to measure acoustic signals generated by the casing reverberation. Parameters of the casing are calculated based on the measured acoustic signals adjusted by an adjustment factor determined by the particular harmonic. The use of harmonics instead of the fundamental resonance frequency allows wellbores with casings having walls thicker than 0.625 inches to be logged.

A method for evaluating a sealing material positioned between a casing of a wellbore and a subsurface formation in which the wellbore is formed includes emitting an acoustic waveform outward from a position within the casing and detecting a return waveform that is generated in response to the acoustic waveform interacting with a region of interest that includes at least a portion of the sealing material. The method includes determining a first time window of the return waveform associated with the region of interest and trimming the return waveform based on the first time window. The method further includes determining a first spectral power density for the first time window of the trimmed return waveform and determining a composition ratio for the region of interest based on the first spectral power density.

Apparatus and techniques are described, such as for obtaining information indicative of a formation resistivity near a casing, such as using an array laterolog apparatus. For example, raw measurements received from a well tool in a borehole near a casing may indicate a resistivity of a geologic formation through which the borehole extends. Any errors or interference in the raw measurements caused by the proximity of the well tool to the casing may be removed to eliminate the casing effect on the raw measurements. In some examples, a signal and formation libraries that include casing specific parameters may be used in conjunction with non-casing optimized signal and formation libraries to perform correction mapping of raw measurements. The corrections and their application to the raw measurements may be based on the position of a well logging tool with respect to a casing termination point.

A method and system for evaluating the cement behind casing and fully inverting acoustic properties of the material, including density and the speed of sound. A density map of the cement sheath is determined using a nuclear logging technique. An acoustic impedance value of the cement sheath is provided, either by measurement using an ultrasonic logging technique or simulated using an acoustic model. The acoustic model may assume a vertical incident plane wave and flat plates for casing and the cement sheath. From the density map and the acoustic impedance value, a map of the speed of sound in the cement sheath, or a gap therein, may be determined.

The present disclosure provides methods and systems for analyzing cement integrity in a depth interval of a wellbore having a multiple string casing with an innermost annulus disposed inside at least one outer annulus. The method includes processing ultrasonic data obtained from ultrasonic measurements on the interval of the wellbore to determine properties of the innermost annulus. The method also includes processing sonic data obtained from sonic measurements on the interval of the wellbore to extract features of the sonic data. The features of the sonic data are input to a machine learning processing to determine properties of both the innermost annulus and the least one outer annulus. Additional processing of ultrasonic and sonic data can also be used to determine properties of both the innermost annulus and the least one outer annulus. These properties can be used to analyze cement integrity in the depth interval of the wellbore.

Systems, methods, and software for determining a thickness of a well casing are described. In some aspects, the thickness of the well casing is determined based on results of comparing a measured waveform and model waveforms. The measured waveform and model waveforms are generated based on operating an acoustic transmitter and an acoustic receiver within a wellbore comprising the well casing.

A model is used to generate corrections to mitigate ideal condition artifacts in acoustic property values of an annular material in a cased wellbore. A mathematical model that generates acoustic property values at ideal conditions introduces artifacts into the acoustic property values. Acoustic measurements of an annular material are used to generate features that represent wellbore conditions and are not accounted for in the mathematical model that generates acoustic property values. A model will generate corrections for acoustic property values of an annular material with the features to yield a more accurate acoustic property profile for the annular material of a cased hole.