A downhole drilling system is disclosed. The system may include a drill bit including first and second electrodes electrically coupled to a pulse-generating circuit to receive pulse drilling signals, a reference sensor in proximity to the drill bit, an additional sensor uphole from the reference sensor, and a sensor analysis system communicatively coupled to the reference sensor and to the additional sensor. The sensor analysis system may be configured to obtain measurements representing responses recorded simultaneously by the reference sensor and by the additional sensor during a pulsed drilling operation in a wellbore, generate modified measurements in which effects of variations in the pulse drilling signal on the measurements representing responses recorded by the additional sensor are reduced based on the measurements representing responses recorded by the reference sensor and determine, based on the modified measurements, a characteristic of a formation downhole from the drill bit.

A downhole drilling system is disclosed. The system may include a drill bit including first and second electrodes electrically coupled to a pulse-generating circuit to receive pulse drilling signals, a reference sensor in proximity to the drill bit, an additional sensor uphole from the reference sensor, and a sensor analysis system communicatively coupled to the reference sensor and to the additional sensor. The sensor analysis system may be configured to obtain measurements representing responses recorded simultaneously by the reference sensor and by the additional sensor during a pulsed drilling operation in a wellbore, generate modified measurements in which effects of variations in the pulse drilling signal on the measurements representing responses recorded by the additional sensor are reduced based on the measurements representing responses recorded by the reference sensor and determine, based on the modified measurements, a characteristic of a formation downhole from the drill bit.

A method for developing design rules for mitigating cutting-induced stick-slip vibration includes determining at least one value for one or more drill bit performance parameters for a design of a drill bit. The one or more drill bit performance parameters include a functional characteristic of a depth of cut controller of the drill bit. The method includes correlating one or more instances of cutting-induced stick-slip vibration for at least one prior drilling operation to the at least one value for the one or more drill bit performance parameters. The method includes generating drill bit design rules that mitigate cutting-induced stick-slip vibration based on the correlating.

A rotary tool for operation within an underground borehole or within tubing in a borehole has a tool body and at least one sensor-containing unit attached to the tool body and positioned to contact the conduit wall. The sensor-containing unit includes an exterior portion to contact the borehole or tubing wall and one or more sensors is located in a cavity between the exterior portion and the tool body. The sensor-containing unit may be formed from the exterior portion, an attachment portion for attachment to the tool body, and one or more connecting portions extending between the attachment and exterior portions, with the sensor-containing cavity between the attachment and exterior portions. Possible rotary tools include drill bits, reamers, mills, stabilizers, and rotary steerable systems.

A rotary tool for operation within an underground borehole or within tubing in a borehole has a tool body and at least one sensor-containing unit attached to the tool body and positioned to contact the conduit wall. The sensor-containing unit includes an exterior portion to contact the borehole or tubing wall and one or more sensors is located in a cavity between the exterior portion and the tool body. The sensor-containing unit may be formed from the exterior portion, an attachment portion for attachment to the tool body, and one or more connecting portions extending between the attachment and exterior portions, with the sensor-containing cavity between the attachment and exterior portions. Possible rotary tools include drill bits, reamers, mills, stabilizers, and rotary steerable systems.

The method for drilling includes extending a borehole from a surface location to a borehole end with a drill string having a bottom hole assembly with a drill bit. A surface sensor and a downhole sensor take measurements used to project borehole features, like the borehole end. The measurements are used to project the borehole end so that the drill bit can be steered through the rock formation. The downhole sensor is separated from the bit location by a plurality of segments. The method includes corrections when the measurements at the downhole location are not the measurements at the bit location. As the drill bit travels, the types of corrections change, including applying an initial Kalman filter, a first adjusted Kalman filter, a second adjusted Kalman filter, and a third adjusted Kalman filter, according to the plurality of segments between the downhole sensor and the bit location.

The method for drilling includes extending a borehole from a surface location to a borehole end with a drill string having a bottom hole assembly with a drill bit. A surface sensor and a downhole sensor take measurements used to project borehole features, like the borehole end. The measurements are used to project the borehole end so that the drill bit can be steered through the rock formation. The downhole sensor is separated from the bit location by a plurality of segments. The method includes corrections when the measurements at the downhole location are not the measurements at the bit location. As the drill bit travels, the types of corrections change, including applying an initial Kalman filter, a first adjusted Kalman filter, a second adjusted Kalman filter, and a third adjusted Kalman filter, according to the plurality of segments between the downhole sensor and the bit location.

Systems and methods for visualizing data from radially-oriented look-ahead sensors coupled to a drill bit are disclosed herein. A system comprises a processor, a memory, and a data analysis module. The data analysis module is operable to receive formation information from each of a plurality of formation sensors coupled to a downhole drilling system, the formation information being associated with one or more properties of a formation at a depth in front of the downhole drilling system, receive angular information from one or more orientation sensors coupled to the downhole drilling system, the angular information being associated with the formation information, compile sensor data based on the formation information and the angular information, and generate a visualization based on the sensor data.

A method that includes deploying a casing with a multi-electrode configuration over a dielectric layer in a downhole environment. The method also includes collecting electromagnetic (EM) measurements using the multi-electrode configuration, and processing the EM measurements to obtain a characterization of fluids in an annulus between the casing and a borehole wall. A related system includes a casing deployed downhole, the casing having a multi-electrode configuration and a dielectric layer between the casing and the multi-electrode configuration. The system also includes a controller for directing collection of EM measurements using the multi-electrode configuration, and a processor that processes the EM measurements to obtain a characterization of fluids in an annulus between the casing and a borehole wall.

Devices, systems, and methods for stabilizing a gyroscopic sensor include bearings supporting a MEMS-type gyroscope located in a shell. The shell rotates around a secondary shaft connected to an extension arm of a primary shaft. A biasing element pre-loads thrust bearings on either side of the shell against the extension arm, which can limit motion of the shell during operation of the sensor, thereby improving measurements made by the sensor.