A method of drilling a borehole in an earth formation includes deploying a drilling assembly including a drill bit and a drill string, and performing a drilling operation according to one or more operational parameters to advance the drilling assembly through the formation, wherein performing the drilling operation includes rotating the drill bit and at least a portion of the drill string. The method also includes, during the advancing, monitoring a downhole condition, determining whether the downhole condition indicates at least one of a cuttings accumulation in the borehole and wear of a downhole component, and in response to the downhole condition indicating the cuttings accumulation or the wear, adjusting at least one operational parameter to induce or adjust an oscillating motion in the drill string, the oscillating motion causing at least one of a reduction in the cuttings accumulation and a reduction of wear of the downhole component.

A method includes receiving, at a computer, an Earth formation characteristic and a cutter characteristic of a cutter of an Earth drill bit and determining, with the computer, a cutting characteristic at an interface between the Earth formation and the cutter based on the Earth formation characteristic and the cutter characteristic using an Earth formation crushing model operating on the computer. The Earth formation crushing model includes an empirical determination of stress at the interface in a first of three mutually perpendicular axes and determinations of stress in the remaining two mutually perpendicular axes that are mathematical functions based on the empirical determination of stress. The method also includes outputting the determined cutting characteristic.

A method includes receiving, at a computer, an Earth formation characteristic and a cutter characteristic of a cutter of an Earth drill bit and determining, with the computer, a cutting characteristic at an interface between the Earth formation and the cutter based on the Earth formation characteristic and the cutter characteristic using an Earth formation crushing model operating on the computer. The Earth formation crushing model includes an empirical determination of stress at the interface in a first of three mutually perpendicular axes and determinations of stress in the remaining two mutually perpendicular axes that are mathematical functions based on the empirical determination of stress. The method also includes outputting the determined cutting characteristic.

An apparatus for determining torque on bit and bending forces in a drilling assembly. The apparatus includes a body having an inner bore defined by an inner wall and having an outer wall, the body also including first and second light bores disposed between the inner wall and the outer wall and a light emitting assembly arranged and configured to cause a light beam to enter the first and second light bores. The assembly further includes first and second light sensors disposed in or at an end of the first and second light bores, respectively, that measure a location where light that enters the first and second light bores contacts the sensors

An apparatus for determining torque on bit and bending forces in a drilling assembly. The apparatus includes a body having an inner bore defined by an inner wall and having an outer wall, the body also including first and second light bores disposed between the inner wall and the outer wall and a light emitting assembly arranged and configured to cause a light beam to enter the first and second light bores. The assembly further includes first and second light sensors disposed in or at an end of the first and second light bores, respectively, that measure a location where light that enters the first and second light bores contacts the sensors

This disclosure provides a downhole drilling system, which comprises a downhole motor, a universal-joint assembly comprising an upper universal joint and a lower universal and a connecting rod connecting the upper universal joint and the lower universal joint, and a measurement sub. The measurement sub is disposed about the connecting rod and the connecting rod extends through the measurement sub in a longitudinal direction thereof.

A cutting element for an earth-boring tool includes a body having a longitudinal axis, a generally planar volume of hard material carried by the body, and a sensor affixed to the body. The sensor may be configured to sense at least one of stress and strain. An earth-boring tool includes a cutting element disposed at least partially within a pocket of a body. Methods of forming cutting elements comprise securing a generally planar volume of hard material to a body, attaching a sensor to the body, and configuring the sensor. Methods of forming earth-boring tools comprise forming a cutting element and securing the cutting element within a recess in a body of the earth-boring tool. Methods of forming wellbores comprise rotating an earth-boring tool comprising a cutting element and measuring at least one of stress and strain.

A cutting element for an earth-boring tool includes a body having a longitudinal axis, a generally planar volume of hard material carried by the body, and a sensor affixed to the body. The sensor may be configured to sense at least one of stress and strain. An earth-boring tool includes a cutting element disposed at least partially within a pocket of a body. Methods of forming cutting elements comprise securing a generally planar volume of hard material to a body, attaching a sensor to the body, and configuring the sensor. Methods of forming earth-boring tools comprise forming a cutting element and securing the cutting element within a recess in a body of the earth-boring tool. Methods of forming wellbores comprise rotating an earth-boring tool comprising a cutting element and measuring at least one of stress and strain.

The present invention relates to a drilling composition comprising an organic phase having at least one linear or branched, cyclic or non-cyclic, saturated hydrocarbon, at least one ester, water or aqueous phase, and at least one additive.

The present invention additionally relates to the use and preparation of the drilling composition, to a drilling system, to a process for making a borehole, to a process for conveying cuttings, to a process for treating a drill head, and to a process for production of oil and/or gas.

A method includes disposing a braze material adjacent a first body and a second body; heating the braze material and forming a transient liquid phase; and transforming the transient liquid phase to a solid phase and forming a bond between the first body and the second body. The braze material includes copper, silver, zinc, magnesium, and at least one material selected from the group consisting of nickel, tin, cobalt, iron, phosphorous, indium, lead, antimony, cadmium, and bismuth.