In some embodiments, a downhole drilling system may include a pulse-generating circuit, a drill bit including a first pair of electrodes electrically coupled to the pulse-generating circuit to receive a first electrical pulse from the pulse-generating circuit and form a first electrical arc between the first pair of electrodes during a pulsed drilling operation. The system further includes a sensor to record responses to the first electrical pulse during the pulsed drilling operation and a sensor analysis system communicatively coupled to the sensor, where the sensor analysis system is configured to obtain a first measurement from the sensor representing the responses recorded by the sensor during the pulsed drilling operation. Additionally, the system may determine a first value of a dielectric constant associated with a portion of a formation in proximity to the drill bit, where the first value of the dielectric constant is based on the first measurement.

In some embodiments, a downhole drilling system may include a pulse-generating circuit, a drill bit including a first pair of electrodes electrically coupled to the pulse-generating circuit to receive a first electrical pulse from the pulse-generating circuit and form a first electrical arc between the first pair of electrodes during a pulsed drilling operation. The system further includes a sensor to record responses to the first electrical pulse during the pulsed drilling operation and a sensor analysis system communicatively coupled to the sensor, where the sensor analysis system is configured to obtain a first measurement from the sensor representing the responses recorded by the sensor during the pulsed drilling operation. Additionally, the system may determine a first value of a dielectric constant associated with a portion of a formation in proximity to the drill bit, where the first value of the dielectric constant is based on the first measurement.

A unified mud-pulse (MP)-electromagnetic (EM) telemetry assembly and a downhole telemetry tool are provided including a downhole EM telemetry transmitter apparatus. The EM telemetry transmitter apparatus comprises a modulator configured to transmit at least one EM signal through transmission medium. The modulator comprises a first reactive circuit and a second reactive circuit, and a plurality of switches controlled by a controller to alternatingly switch the modulator between a first configuration and a second configuration. The EM signals are transmitted by passing one of the reactive circuits and bypassing the other reactive circuit.

A method includes generating a ranging model of a drilling wellbore to be drilled and generating a predicted signal along measured depths of the drilling wellbore based on the ranging model. The method includes performing the following operations until the drilling wellbore has been drilled to a defined depth. The following operations include drilling, with a drill string, the drilling wellbore to an increment of the defined depth and detecting, by a sensor positioned on the drill string, an electromagnetic field emanating from a target wellbore. The following operations include determining ranging measurements to the target wellbore at the increment based on the electromagnetic field and calibrating the predicted signal based on the ranging measurements. The following operations include determining ranging accuracy for all deeper depths in the wellbore and making drilling decisions or adjusting drilling operations based on the predicted ranging accuracy for deeper depths.

A method includes generating a ranging model of a drilling wellbore to be drilled and generating a predicted signal along measured depths of the drilling wellbore based on the ranging model. The method includes performing the following operations until the drilling wellbore has been drilled to a defined depth. The following operations include drilling, with a drill string, the drilling wellbore to an increment of the defined depth and detecting, by a sensor positioned on the drill string, an electromagnetic field emanating from a target wellbore. The following operations include determining ranging measurements to the target wellbore at the increment based on the electromagnetic field and calibrating the predicted signal based on the ranging measurements. The following operations include determining ranging accuracy for all deeper depths in the wellbore and making drilling decisions or adjusting drilling operations based on the predicted ranging accuracy for deeper depths.

A method of estimating a directional parameter of a downhole component includes deploying a borehole string in a borehole, the borehole string including the downhole component, the downhole component being rotatable, the downhole component including a gyroscope device and a magnetometer device. The method also includes collecting gyroscope measurement data from the gyroscope device and magnetic field measurement data from the magnetometer device during rotation of the downhole component, and estimating, by a processor, the directional parameter of the downhole component, where the estimating includes correcting the gyroscope measurement data based on the magnetic field measurement data.

A method of estimating a directional parameter of a downhole component includes deploying a borehole string in a borehole, the borehole string including the downhole component, the downhole component being rotatable, the downhole component including a gyroscope device and a magnetometer device. The method also includes collecting gyroscope measurement data from the gyroscope device and magnetic field measurement data from the magnetometer device during rotation of the downhole component, and estimating, by a processor, the directional parameter of the downhole component, where the estimating includes correcting the gyroscope measurement data based on the magnetic field measurement data.

A method for ranging to locate a target borehole. The method may include disposing a bottom hole assembly (BHA) into an intercept borehole, disposing a downhole tool into a reference borehole, imaging a target borehole for the intercept borehole to get a first set of measurement, imaging the target borehole from the reference borehole to get a second set of measurements, and combining the first set of measurements and the second set of measurements to determine a direction and distance to the target borehole form the intercept borehole.

A method for ranging to locate a target borehole. The method may include disposing a bottom hole assembly (BHA) into an intercept borehole, disposing a downhole tool into a reference borehole, imaging a target borehole for the intercept borehole to get a first set of measurement, imaging the target borehole from the reference borehole to get a second set of measurements, and combining the first set of measurements and the second set of measurements to determine a direction and distance to the target borehole form the intercept borehole.

Provided are systems and methods for mapping hydrocarbon reservoirs. Operations include disposing an electromagnetic (EM) transmitter and an EM receiver into first and second wellbores of first and second wells, respectively, penetrating a resistive layer of a subsurface formation bounded by first and second conductive layers. The EM transmitter and receiver each being disposed at depths proximate to intersections of the first and second wellbores and the resistive layer, respectively. The operations further including transmitting an EM signal between the EM transmitter and receiver via the resistive layer, determining transport properties associated with propagation of the EM signal from the EM transmitter to the EM receiver via the resistive layer, and determining the presence of an anomaly in at least one of the conductive layers based on the travel time.