A sonic tool is activated in a well having multiple casings and annuli surrounding the casing. Detected data is preprocessed using slowness time coherence (STC) processing to obtain STC data. The STC data is provided to a machine learning module which has been trained on labeled STC data. The machine learning module provides an answer product regarding the states of the borehole annuli which may be used to make decision regarding remedial action with respect to the borehole casings. The machine learning module may implement a convolutional neural network (CNN), a support vector machine (SVM), or an auto-encoder.

A system for monitoring data quality in a drilling operation includes a controller and a plurality of data sources configured to provide data to the controller. The controller is configured to receive data from a plurality of data sources during a drilling operation; apply data quality rules to the received data; calculate a score for each data source of the plurality of data sources based on adherence of the received data for that data source to the data quality rules; compare the calculated scores for the plurality of data sources to determine which calculated scores meet or exceed a threshold score; receive a selection of one of the plurality of data sources having a calculated score that meets or exceeds the threshold score; and use the data from the selected data source. Methods and non-transitory machine-readable media for monitoring data quality are also provided.

A method is described for lithofacies classification including receiving well logs representative of a subsurface volume of interest; deriving lithofacies from the well logs based on lithofacies cutoffs; calculating thickness of individual beds of the lithofacies; defining thickness thresholds based on the thickness of individual beds; upscaling to filter thin beds from thick beds based on the thickness thresholds; and classifying lithofacies intervals based on the upscaling. The method may be executed by a computer system.

A well tool can be used in a wellbore that can measure characteristics of an object in the wellbore. The well tool includes an ultrasonic transducer for generating an ultrasonic wave in a medium of the wellbore. The ultrasonic transducer includes a front layer, a rear layer, backing material coupled to the rear layer, and piezoelectric material coupled to the front layer and to the backing material. The rear layer can improve signal-to-noise ratio of the transducer in applications such as imaging and caliper applications.

A method can include acquiring imagery of an exposed surface of the Earth; generating a multi-dimensional model based at least in part on the imagery; generating synthetic seismic data utilizing the multi-dimensional model; acquiring seismic data of a subsurface region of the Earth; performing a search that matches a portion of the acquired seismic data and a portion of the synthetic seismic data; and characterizing the subsurface region of the Earth based at least in part on the portion of the synthetic seismic data.

Seismic data processing using one or more non-linear stacking enabling detection of weak signals relative to noise levels. The non-linear stacking includes a double phase, a double phase-weighted, a real phasor, a squared real phasor, a phase and an N-th root stack. Microseismic signals as recorded by one or more seismic detectors and transformed by transforming the signal to enhance detection of arrivals. The transforms enable the generation of an image, or map, representative of the likelihood that there was a source of seismic energy occurring at a given point in time at a particular point in space, which may be used, for example, in monitoring operations such as hydraulic fracturing, fluid production, water flooding, steam flooding, gas flooding, and formation compaction.

A system for monitoring data quality in a drilling operation includes a controller and a plurality of data sources configured to provide data to the controller. The controller is configured to receive data from a plurality of data sources during a drilling operation; apply data quality rules to the received data; calculate a score for each data source of the plurality of data sources based on adherence of the received data for that data source to the data quality rules; compare the calculated scores for the plurality of data sources to determine which calculated scores meet or exceed a threshold score; receive a selection of one of the plurality of data sources having a calculated score that meets or exceeds the threshold score; and use the data from the selected data source. Methods and non-transitory machine-readable media for monitoring data quality are also provided.

Cement bonding evaluation and logging in a wellbore environment are described. The cement bonding evaluation is performed using data associated with and processed from the measurement of sonic waves directed to and dissipated by the casing present in the wellbore.

The disclosure relates to determining rock properties of subterranean formations and learning the distribution of hydrocarbons in the formations. A geometrical element spread function is disclosed that quantifies distortion of the geology as seen by the geophysicists who process seismic images of the subterranean formations. A method of determining the rock properties using the seismic images and synthetic images is provided. In one example, the method includes: (1) obtaining seismic data from a subterranean formation using a seismic acquisition system, (2) generating one or more seismic images of the subterranean formation using the seismic data, (3) creating one or more synthetic images from the one or more seismic images, and (4) determining rock properties of the subterranean formation based on the one or more seismic images and the one or more synthetic images.

A method for determining an internal multiple attenuated seismic image is disclosed. The method includes obtaining a seismic dataset composed of a plurality of seismic traces and for each seismic trace determining an internal multiple trace based, at least in part, on a nested truncated correlation and a bounded convolution of the seismic trace with itself. The method further includes determining an internal multiple attenuated seismic trace based, at least in part, on subtracting the internal multiple trace from the seismic trace and combining the internal multiple attenuated seismic trace to form the internal multiple attenuated seismic image. A system including a seismic source, a plurality of seismic receivers, and a seismic processor for executing the method is disclosed.