A drilling system for drilling a borehole. The drilling system may include a drill string, a drill bit coupled to the drill string, a mud motor coupled to the drill string uphole of the drill bit and operable to rotate the drill bit via a driveshaft, a bearing assembly coupled to a downhole end of the mud motor and operable to support the driveshaft, and a rotary steerable system (“RSS”) operable to push the drill bit in a desired direction via pads extended using drilling fluid flowing through the driveshaft and to the RSS. The bearing assembly may include bearings positioned circumferentially around a bore of the bearing assembly, a fluid flowpath through the bearings to allow drilling fluid to pass through the bearings, and a choke assembly positioned in the fluid flowpath and operable to restrict a flow of the drilling fluid through the fluid flowpath.

Methods and systems for supply of fuel for a turbine-driven fracturing pump system used in hydraulic fracturing may be configured to identify when the supply pressure of primary fuel to a plurality of gas turbine engines of a plurality of hydraulic fracturing units falls below a set point, identify a gas turbine engine of the fleet of hydraulic fracturing units operating on primary fuel with highest amount of secondary fuel available, and to selectively transfer the gas turbine engine operating on primary fuel with the highest amount of secondary fuel from primary fuel operation to secondary fuel operation. Some methods and systems may be configured to transfer all gas turbine engines to secondary fuel operation and individually and/or sequentially restore operation to primary fuel operation and/or to manage primary fuel operation and/or secondary fuel operation for portions of the plurality of gas turbine engines.

An apparatus for removing rubber stator material from inside a housing includes a head, at least one blade, and an actuator. For example, the apparatus can be used to core out rubber material from the housing so new material can be molded therein. Also, the apparatus can be used to cut back excess rubber material newly molded in the housing. The head is rotated about an axis and is moved along the axis relative to the housing. The at least one blade is pivotably connected to the head and removes the rubber stator material at least partially from inside the housing with the rotation and movement of the head through the housing. The actuator is associated with the at least one blade and is operable to adjust a pivot of the at least one blade relative to the head.

An apparatus for removing rubber stator material from inside a housing includes a head, at least one blade, and an actuator. For example, the apparatus can be used to core out rubber material from the housing so new material can be molded therein. Also, the apparatus can be used to cut back excess rubber material newly molded in the housing. The head is rotated about an axis and is moved along the axis relative to the housing. The at least one blade is pivotably connected to the head and removes the rubber stator material at least partially from inside the housing with the rotation and movement of the head through the housing. The actuator is associated with the at least one blade and is operable to adjust a pivot of the at least one blade relative to the head.

A drill string system includes a drill bit disposed at a distal end of a drill string. A clutch is coupled with the drill bit. A mud motor is coupled to the clutch, and the mud motor is operable to receive a drilling fluid therein and transfer torque to the drill bit through the clutch. The clutch disengages upon application of a torque exceeding a predetermined threshold.

A drill string system includes a drill bit disposed at a distal end of a drill string. A clutch is coupled with the drill bit. A mud motor is coupled to the clutch, and the mud motor is operable to receive a drilling fluid therein and transfer torque to the drill bit through the clutch. The clutch disengages upon application of a torque exceeding a predetermined threshold.

A drilling system includes a drill string, a plurality of sensors, and a computing system. The drill string includes a downhole motor. The sensors are coupled to the drill string. The computing system is coupled to the sensors. The computing system is configured to compute, based on measurements provided by the sensors, a motor stall index, and to determine, by comparing the motor stall index to a motor stall threshold, whether the downhole motor has stalled. The computing system is also configured to, responsive to a determination that the downhole motor has stalled, adjust operation of the drill string to restart the downhole motor.

A drilling system includes a drill string, a plurality of sensors, and a computing system. The drill string includes a downhole motor. The sensors are coupled to the drill string. The computing system is coupled to the sensors. The computing system is configured to compute, based on measurements provided by the sensors, a motor stall index, and to determine, by comparing the motor stall index to a motor stall threshold, whether the downhole motor has stalled. The computing system is also configured to, responsive to a determination that the downhole motor has stalled, adjust operation of the drill string to restart the downhole motor.

High frequency oscillation (HFO) comes in at least two types. Type 1 HFO is lower frequency and often associated with a motor. Type 2 HFO is higher frequency and often independent of a motor. To mitigate torsional strain due to Type 2 HFO, an HFO mitigation mechanism can be placed based on an oscillation node location to move the oscillation node to a new position which may be uphole of a tool or the BHA, or to a less vulnerable location. Mitigation can also include placing an energy damping component based on the oscillation node. This may be at a high displacement location distanced from the oscillation node, or may include placement at the oscillation node with an additional HFO mitigation mechanism to move the oscillation node away from the installation location. Oscillations may be damped by using any combination of flow restrictions, fluid bypasses, or axially compliant elements.

A motor bypass valve diverts drilling fluid away from a downhole motor when the motor is off bit. Bypassing the downhole motor reduces the shock and vibration on the BHA caused by the downhole motor, thereby reducing the damage to the BHA. The motor bypass valve may divert fluid out of a housing or into a bore through the rotor of the downhole motor.