System and methods of petrophysical modeling are disclosed. Training data for modeling a reservoir formation surrounding a wellbore drilled within the reservoir formation is received via a network from one or more data sources. A machine learning model is trained using symbolic regression to determine a formation model representing the reservoir formation, based on the training data received from the data source(s). At least one property of the reservoir formation is estimated, based on the formation model. A downhole operation is performed along the wellbore within the reservoir formation, based on the at least one estimated property.

System and methods of petrophysical modeling are disclosed. Training data for modeling a reservoir formation surrounding a wellbore drilled within the reservoir formation is received via a network from one or more data sources. A machine learning model is trained using symbolic regression to determine a formation model representing the reservoir formation, based on the training data received from the data source(s). At least one property of the reservoir formation is estimated, based on the formation model. A downhole operation is performed along the wellbore within the reservoir formation, based on the at least one estimated property.

Methods, systems, devices, and products for well logging. Methods include conveying a logging tool in the borehole on a carrier; obtaining a borehole image over at least one interval of borehole depth from well logging measurements with a downhole imaging instrument; obtaining acoustic information representative of acoustic reflections from a far-field region of the formation; obtaining quantitative borehole fluid information indicative of properties of a formation fluid in a near-field region of the borehole; generating a borehole connectivity fracture model of the formation in dependence upon the borehole image, the quantitative borehole fluid information, and the acoustic information. Methods may include identifying near-field fractures from the borehole image, and/or identifying far-field fractures from the acoustic information. Methods may include generating a fracture interpretation correlating the near-field fractures with the far-field fractures, and generating the borehole connectivity fracture model of the formation in dependence upon the fracture interpretation.

Methods, systems, devices, and products for well logging. Methods include conveying a logging tool in the borehole on a carrier; obtaining a borehole image over at least one interval of borehole depth from well logging measurements with a downhole imaging instrument; obtaining acoustic information representative of acoustic reflections from a far-field region of the formation; obtaining quantitative borehole fluid information indicative of properties of a formation fluid in a near-field region of the borehole; generating a borehole connectivity fracture model of the formation in dependence upon the borehole image, the quantitative borehole fluid information, and the acoustic information. Methods may include identifying near-field fractures from the borehole image, and/or identifying far-field fractures from the acoustic information. Methods may include generating a fracture interpretation correlating the near-field fractures with the far-field fractures, and generating the borehole connectivity fracture model of the formation in dependence upon the fracture interpretation.

Embodiments of the present disclosure provide a ferromagnetic object detection device and a method for detecting a tubing coupling. The ferromagnetic object detection device includes a support tube, a magnetic field generating device and a magnetic detection device. The support tube includes a space penetrating in a first direction; the magnetic field generating device is located on an outer sidewall of the support tube and configured to generate a magnetic field; the magnetic field detection device includes a first magnetic field detection element, a second magnetic field detection element and a third magnetic field detection element.

Embodiments of the present disclosure provide a ferromagnetic object detection device and a method for detecting a tubing coupling. The ferromagnetic object detection device includes a support tube, a magnetic field generating device and a magnetic detection device. The support tube includes a space penetrating in a first direction; the magnetic field generating device is located on an outer sidewall of the support tube and configured to generate a magnetic field; the magnetic field detection device includes a first magnetic field detection element, a second magnetic field detection element and a third magnetic field detection element.

Various embodiments include apparatus and methods to estimate properties of rock, drill bit, or a combination thereof associated with a drilling operation. The properties can include, but are not limited to, rock chip size, drill bit dullness, drilling efficiency, or a combination selected from rock chip size, drill bit dullness, and drilling efficiency. The estimate may be accomplished from correlating detected acoustic emission with detected electromagnetic emissions. In various embodiments, formation brittleness may be determined. The various estimates may be used to direct a drilling operation. Additional apparatus, systems, and methods are disclosed.

Various embodiments include apparatus and methods to estimate properties of rock, drill bit, or a combination thereof associated with a drilling operation. The properties can include, but are not limited to, rock chip size, drill bit dullness, drilling efficiency, or a combination selected from rock chip size, drill bit dullness, and drilling efficiency. The estimate may be accomplished from correlating detected acoustic emission with detected electromagnetic emissions. In various embodiments, formation brittleness may be determined. The various estimates may be used to direct a drilling operation. Additional apparatus, systems, and methods are disclosed.

A method can include receiving channels of data from equipment responsive to operation of the equipment in an environment where the equipment and environment form a dynamic system; defining a particle filter that localizes a time window with respect to the channels of data; applying the particle filter at least in part by weighting particles of the particle filter using the channels of data, where each of the particles represents a corresponding time window; and selecting one of the particles according to its weight as being the time window of an operational state of the dynamic system.

A method can include receiving channels of data from equipment responsive to operation of the equipment in an environment where the equipment and environment form a dynamic system; defining a particle filter that localizes a time window with respect to the channels of data; applying the particle filter at least in part by weighting particles of the particle filter using the channels of data, where each of the particles represents a corresponding time window; and selecting one of the particles according to its weight as being the time window of an operational state of the dynamic system.