A well-logging tool may include a sonde housing and a radiation generator carried by the sonde housing. The radiation generator may include a generator housing, a target carried by the generator housing, a charged particle source carried by the generator housing to direct charged particles at the target, and at least one voltage source coupled to the charged particle source. The at least one voltage source may include a voltage ladder comprising a plurality of voltage multiplication stages coupled in a uni-polar configuration, and at least one loading coil coupled at at least one intermediate position along the voltage ladder. The well-logging tool may further include at least one radiation detector carried by the sonde housing.

A wellbore caliper includes an actuator housing pivotally connected at one end to a well logging instrument housing and an actuator disposed in the housing and operable to extend and retract laterally extensible measuring arms.

A wellbore caliper includes an actuator housing pivotally connected at one end to a well logging instrument housing and an actuator disposed in the housing and operable to extend and retract laterally extensible measuring arms.

In accordance with some embodiments of the present disclosure, methods and systems for modeling an advanced 3-dimensional bottom-hole assembly are disclosed. The method may include determining a drill string property for a drill string having a rotary steerable drill bit; determining a drilling parameter for a drilling operation; generating a finite element model of the drill string based on the drill string property and the drilling parameter; performing a vibrational analysis of the finite element model; and predicting a drill string behavior during the drilling operation based on the vibrational analysis, the drill string behavior including a directional behavior, rate of penetration, or drilling efficiency of the rotary steerable drill bit.

An example method includes determining a frequency response of a tuned pulse to be transmitted from a transmission element. A matching frequency envelope corresponding to a frequency envelope of the frequency response may be determined. A time domain signal corresponding to the matching frequency envelope may be determined. A series of digital pulses corresponding to the time domain signal may be determined. An analog output at a switching amplifier corresponding to the series of digital pulses may be generated. A transmission element may be excited with the analog output.

An example system for operation in a borehole in a hydrocarbon-bearing rock formation includes a logging tool for detecting one or more conditions in the borehole. The logging tool includes a tool body and a 4D printed sensing element. The 4D printed sensing element includes a 3D printed shape-memory material configured to alter in at least one spatial dimension in response to one or more stimuli, thereby generating a data signal. The example system includes a data recording device in communication with the logging tool to receive and record one or more data signals transmitted from the logging tool.

A method for mapping a cased wellbore, the method comprising providing a cased wellbore; and routing a sensor assembly through said cased wellbore to measure forces applied to said sensor assembly.

A system comprises a wellbore having a plurality of casings disposed therein and one or more electromagnetic coils disposed within the wellbore. The one or more electromagnetic coils are configured to generate and direct one or more excitation signals toward the plurality of casings and receive one or more response signals based on interactions of the one or more excitation signals with the plurality of casings. The system further comprises a casing evaluation module comprising a processor and memory and communicably coupled to the one or more electromagnetic coils. The casing evaluation module is operable to determine whether defect exists in at least one of the plurality of casings using a first response signal received from the one or more electromagnetic coils and elemental defect information, the elemental defect information comprising a plurality of combinations of small defect information.

A system comprises a wellbore having a plurality of casings disposed therein and one or more electromagnetic coils disposed within the wellbore. The one or more electromagnetic coils are configured to generate and direct one or more excitation signals toward the plurality of casings and receive one or more response signals based on interactions of the one or more excitation signals with the plurality of casings. The system further comprises a casing evaluation module comprising a processor and memory and communicably coupled to the one or more electromagnetic coils. The casing evaluation module is operable to determine whether defect exists in at least one of the plurality of casings using a first response signal received from the one or more electromagnetic coils and elemental defect information, the elemental defect information comprising a plurality of combinations of small defect information.

The shape and size of a borehole may be characterized downhole, using measurements of the borehole shape in conjunction with a catalog of shapes against which the measured shape is matched. A unique identifier for the measured borehole shape, and optionally a size parameter, may be transmitted to a surface facility, generally saving bandwidth compared with the transmission of the raw measured borehole-shape data. Alternatively or additionally, downhole measurements may be adjusted based on the measured shape. Additional methods, apparatus, and systems are disclosed.