A method includes disposing a downhole tool having a magnet assembly into a wellbore. The method includes generating, using the magnet assembly, a magnetic polarization in a volume into a subterranean region about the wellbore. The method also includes emitting an excitation in the magnetic polarization in the volume in the subterranean region. The method includes detecting, by at least one antenna, a nuclear magnetic resonance response to the excitation of the volume in the subterranean region. The method also includes determining a property of the subterranean region based on the nuclear magnetic resonance response.

A method includes disposing a downhole tool having a magnet assembly into a wellbore. The method includes generating, using the magnet assembly, a magnetic polarization in a volume into a subterranean region about the wellbore. The method also includes emitting an excitation in the magnetic polarization in the volume in the subterranean region. The method includes detecting, by at least one antenna, a nuclear magnetic resonance response to the excitation of the volume in the subterranean region. The method also includes determining a property of the subterranean region based on the nuclear magnetic resonance response.

A communication system that is positionable in a wellbore can include a first transceiver positioned externally to a casing string. The first transceiver can be operable to detect a presence or an absence of a surface wave; determine a location of a fluid in the wellbore based on the presence or the absence of the surface wave; and transmit data indicative of the location to a second transceiver. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is non-transverse to a direction of propagation of the surface wave. The communication system can also include the second transceiver, which can be positioned externally the casing string and operable to receive the data.

A communication system that is positionable in a wellbore can include a first transceiver positioned externally to a casing string. The first transceiver can be operable to detect a presence or an absence of a surface wave; determine a location of a fluid in the wellbore based on the presence or the absence of the surface wave; and transmit data indicative of the location to a second transceiver. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is non-transverse to a direction of propagation of the surface wave. The communication system can also include the second transceiver, which can be positioned externally the casing string and operable to receive the data.

The disclosed embodiments include systems and methods to evaluate a formation dip of a formation bedding. The system includes memory configured to store a color image indicative of a log of a formation bedding. The system also includes a processor configured to execute instructions to filter colors of the color image to determine one or more cusps of the formation dip, and cross correlate a reference wave with the one or more cusps of the formation dip to match curvatures of the reference wave with the one or more cusps of the formation dip illustrated in the color image, wherein the curvatures of the reference wave are based on one or more parameters of the formation bedding. The processor is further operable to generate a wave that matches the one or more cusps of the formation dip with the reference wave, where the wave is indicative of the formation dip.

The disclosed embodiments include systems and methods to evaluate a formation dip of a formation bedding. The system includes memory configured to store a color image indicative of a log of a formation bedding. The system also includes a processor configured to execute instructions to filter colors of the color image to determine one or more cusps of the formation dip, and cross correlate a reference wave with the one or more cusps of the formation dip to match curvatures of the reference wave with the one or more cusps of the formation dip illustrated in the color image, wherein the curvatures of the reference wave are based on one or more parameters of the formation bedding. The processor is further operable to generate a wave that matches the one or more cusps of the formation dip with the reference wave, where the wave is indicative of the formation dip.

A magneto-quasistatic field may be used to align hydrogen of materials within a structure and/or to disrupt the alignment of hydrogen of materials within the structure. Realignment of the hydrogen after the disruption may cause emission of energy from the hydrogen. The characteristic(s) of the energy may be detected and used to generate image(s) of interior portion(s) of the structure.

A magneto-quasistatic field may be used to align hydrogen of materials within a structure and/or to disrupt the alignment of hydrogen of materials within the structure. Realignment of the hydrogen after the disruption may cause emission of energy from the hydrogen. The characteristic(s) of the energy may be detected and used to generate image(s) of interior portion(s) of the structure.

The present disclosure provides a device and methods for determining the original stratum direction of a core. The device includes a confining pressure pump, a resistance meter, and a core holder composed of upper and lower portions. The present disclosure further provides three methods for determining the original stratum direction of the core. The three methods respectively use the device to measure resistance values at different positions of the core, and compare a test result with an imaging result of resistivity imaging logging data to determine the rock direction of the core in a stratum.

The present disclosure provides a device and methods for determining the original stratum direction of a core. The device includes a confining pressure pump, a resistance meter, and a core holder composed of upper and lower portions. The present disclosure further provides three methods for determining the original stratum direction of the core. The three methods respectively use the device to measure resistance values at different positions of the core, and compare a test result with an imaging result of resistivity imaging logging data to determine the rock direction of the core in a stratum.