Abstract: A drilling system may determine a change in motor torque and/or a pressure drop of a downhole motor based on a flow of a drilling fluid through the downhole motor. The drilling system may determine a change in bit torque of a bit with respect to a change in a weight on bit of the bit. Based at least in part on the change in motor pressure and the change in bit torque of the bit with respect to the change in the weight on bit of the bit, the drilling system may adjust a flow rate of the drilling fluid through the downhole motor to reduce a frequency of motor stalls of the downhole motor.

Abstract: Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

Abstract: A cutting element assembly includes a cutter support including a cutter bore. A cutting element is in the cutter bore and a resilient element is integral with the cutter support. The resilient element is longitudinally compressible and has a displacement of greater than 0.1 mm and optionally less than 2 mm. Another cutting assembly includes a cutter support coupled to multiple cutting elements. A resilient element of the cutter support is compressible based on a force applied to the cutter support through one or more of the cutting elements. The resilient element can include a slit in the cutter support. A slit may, for instance, extend perpendicular or transverse to an axis of the cutting elements and allow the cutter support to flex and close off or reduce a size of the slit when forces act on one or more of the cutting elements.

Abstract: Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

Abstract: Embodiments described herein relate to systems and methods of cylinder deactivation in compression-ignition engines. An engine described herein can include N cylinders, with N being an integer of at least 2, with each cylinder including an inner surface, a piston disposed and configured to move in each cylinder of the N cylinders, an intake port, an exhaust port, and a fuel injector. The piston and the inner surface define a combustion chamber. A method of operating the compression ignition engine includes injecting a fuel into each of the combustion chambers, combusting substantially all of the fuel in the compression ignition engine, monitoring engine load of the compression ignition engine, and deactivating a cylinder of the N cylinders upon a decrease in load to less than (N?1)/N×FL, wherein FL is a full load at a given engine speed.

Abstract: A tool, for removing a cutting bit from a rotor of a rotor assembly of a machine, includes one or more input interfaces and one or more lighting units. The one or more input interfaces are configured to be actuated to perform one or more functions associated with removing the cutting bit from the rotor. The one or more lighting units are configured to be activated upon the actuation of the one or more input interfaces to illuminate at least a portion of the rotor assembly when performing the one or more functions associated with removing the cutting bit from the rotor.

Abstract: Methods and systems are provided that determine data characterizing spatial variation of vibrational dysfunction (such as HFTO) along the BHA of a drilling system. In embodiments, such data can be determined from a minimal set of measurements of any or all of four variables that include: vibration amplitude; vibration wavelength; vibration frequency; and the axial position of the first vibrational node. In embodiments, such data can be determined from measurements of vibration amplitude and vibration frequency of a BHA at two fixed positions along the BHA (e.g., with two sensors offset axially along the BHA). In other embodiments, such data can be generated from the estimated position of the first vibrational node and measurements of vibration amplitude and vibration frequency by a single sensor disposed at a fixed axial position along the BHA.

Abstract: A tool, for removing a cutting bit from a rotor of a rotor assembly of a machine, includes one or more input interfaces and one or more lighting units. The one or more input interfaces are configured to be actuated to perform one or more functions associated with removing the cutting bit from the rotor. The one or more lighting units are configured to be activated upon the actuation of the one or more input interfaces to illuminate at least a portion of the rotor assembly when performing the one or more functions associated with removing the cutting bit from the rotor.

Abstract: A retention system for retaining a milling drum to a driveshaft of a milling assembly. The driveshaft is powered to drive the milling drum about an axis. The retention system includes a retention member coupled to the driveshaft between a first position and a second position. In the first position, the retention member restricts a disengagement between an engagement surface of the driveshaft and a mating surface of the milling drum, inhibiting a release of the milling drum from the driveshaft along the axis. In the second position, the retention member provides clearance for the disengagement of the engagement surface and the mating surface, facilitating the release of the milling drum from the driveshaft along the axis.

Abstract: A system for transferring torque from a driveshaft to a milling drum mountable on the driveshaft. The system includes a first coupler removably coupled to the driveshaft to co-rotate with the driveshaft. The first coupler defines an engagement surface. Also, the system includes a second coupler removably coupled to the milling drum. The second coupler defines a mating surface engageable with the engagement surface of the first coupler to engage the second coupler to the first coupler and transfer torque from the driveshaft to the milling drum.

Abstract: In a drill bit which has hard-faced cutting or gauge protection elements positioned to be in direct contact with subterranean formation as the bit is rotated, at least one of these elements includes a window positioned to be in direct contact with the formation or cuttings from the formation as the bit rotates and moves forward to drill into the formation. Electromagnetic radiation with wavelength in the range from 100 nm to 2600 nm is transmitted through the window to the formation in contact with the window. Electromagnetic radiation such as fluorescence that returns through the same window is received by a spectrometer. The source and receiver of electromagnetic radiation are both accommodated within the downhole drilling equipment but spaced from the windowed element. The electromagnetic radiation travels along light guides from the source to the window and from the window to the receiver.

Abstract: A stabilizer can include an outer collar, an inner sleeve, and a locking mechanism. The locking mechanism is changeable between a first mode in which the outer collar is rotationally fixed to the inner sleeve and a second mode in which the outer collar is rotationally isolated relative to the inner sleeve. The stabilizer may include an active or passive system for changing modes. An example passive device may include a magnetic clutch where the detected force overcomes magnetic forces to change mode. The stabilizer can be used to mitigate whirl on a rotating device by switching the rotating device between a rotating mode and a non-rotating mode. In the rotating mode, outer collar may rotate with the inner sleeve. In the non-rotating mode, the outer collar may be rotationally isolated from the inner sleeve.

Abstract: 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.

Abstract: Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

Abstract: Some embodiments described herein relate to a method of operating a compression ignition engine. The method of operating the compression ignition engine includes opening an intake valve to draw a volume of air into a combustion chamber, closing an intake valve, and moving a piston from a bottom-dead-center (BDC) position to a top-dead-center (TDC) position in the combustion chamber at a compression ratio of at least about 15:1. The method further includes injecting a volume of fuel into the combustion chamber at an engine crank angle between about 330 degrees and about 365 degrees during a first time period. The fuel has a cetane number less than about 40. The method further includes combusting substantially all of the volume of fuel. In some embodiments, a delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms.

Abstract: A method for measuring at least one property of a sample includes obtaining a sample of fluid including at least fines from a downhole environment, exposing the sample to a magnetic field, measuring a magnetic susceptibility of the fines in the sample in response to the magnetic field, and identifying at least one mineral present in the fines based at least partially on the magnetic susceptibility.

Abstract: Embodiments described herein relate to systems and methods of cylinder deactivation in compression-ignition engines. An engine described herein can include N cylinders, with N being an integer of at least 2, with each cylinder including an inner surface, a piston disposed and configured to move in each cylinder of the N cylinders, an intake port, an exhaust port, and a fuel injector. The piston and the inner surface define a combustion chamber. A method of operating the compression ignition engine includes injecting a fuel into each of the combustion chambers, combusting substantially all of the fuel in the compression ignition engine, monitoring engine load of the compression ignition engine, and deactivating a cylinder of the N cylinders upon a decrease in load to less than (N?1)/N×FL, wherein FL is a full load at a given engine speed.

Abstract: A rotary tool for operation within an underground wellbore or within tubing in a wellbore has at least one force-sensitive element attached to the tool body and positioned to contact the conduit wall, wherein the force-sensitive element comprises an outer portion to contact the wellbore or tubing wall, at least one connecting portion which is more compliant than the outer portion and through which the outer portion is connected to the tool body, and at least one sensor responsive to force on the outer portion transmitted through the force-sensitive element to the tool body. The sensors may resolve forces into measurable forces on three axes. Possible rotary tools include drill bit, reamer, mill, stabilizer and rotary steerable system for a drill bit.

Abstract: A retention system for retaining a milling drum to a driveshaft of a milling assembly. The driveshaft is powered to drive the milling drum about an axis. The retention system includes a retention member coupled to the driveshaft between a first position and a second position. In the first position, the retention member restricts a disengagement between an engagement surface of the driveshaft and a mating surface of the milling drum, inhibiting a release of the milling drum from the driveshaft along the axis. In the second position, the retention member provides clearance for the disengagement of the engagement surface and the mating surface, facilitating the release of the milling drum from the driveshaft along the axis.

Abstract: A system for transferring torque from a driveshaft to a milling drum mountable on the driveshaft. The system includes a first coupler removably coupled to the driveshaft to co-rotate with the driveshaft. The first coupler defines an engagement surface. Also, the system includes a second coupler removably coupled to the milling drum. The second coupler defines a mating surface engageable with the engagement surface of the first coupler to engage the second coupler to the first coupler and transfer torque from the driveshaft to the milling drum.