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 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.

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.

An ultrasonic imaging method is provided. A wideband acoustic pulse is fired at a wall. A wideband response signal is received. The wideband response signal is processed to select an impedance measurement frequency. A wavelet having a characteristic frequency approximately equal to the impedance measurement frequency is fired. A wavelet response signal is received. A reflection coefficient is determined from the wavelet response signal. An impedance measurement is calculated from the reflection coefficient. Related tools and systems are also disclosed.