A flow splitting device for gas reverse circulation drilling, including: an upper joint for connecting with a double-wall drill pipe; an inner tube which is arranged in the upper joint and defines a first passageway in communication with an inner chamber of the double-wall drill pipe, a second passageway in communication with an annular space in the double-wall drill pipe formed between the inner tube and the upper joint; a lower joint, having an upper end fixedly connected with the upper joint and a lower end for connecting with a drill tool; and a flow guiding member provided between the upper joint and the lower joint. A flexible sealing mechanism is provided outside the upper joint. The flexible sealing mechanism extends radially outward relative to the upper joint and the lower joint to form a sealing contact with a wellbore wall.

Provided, in one aspect, is a downhole torque limiter, comprising a tubular housing; a pipe positioned within the tubular housing; one or more clutch mechanisms positioned between the pipe and the tubular housing, the one or more clutch mechanisms configured to move between a engaged state to fix the tubular housing relative to the pipe and a disengaged state to allow with the tubular housing to rotate relative to the pipe; and a fluid control system coupled with an exterior of the one or more clutch mechanisms, the fluid control system configured to allow the one or more clutch mechanisms to move from the engaged state to the disengaged state based upon sensing movement of the pipe relative to the tubular housing.

Provided, in one aspect, is a downhole torque limiter, comprising a tubular housing; a pipe positioned within the tubular housing; one or more clutch mechanisms positioned between the pipe and the tubular housing, the one or more clutch mechanisms configured to move between a engaged state to fix the tubular housing relative to the pipe and a disengaged state to allow with the tubular housing to rotate relative to the pipe; and a fluid control system coupled with an exterior of the one or more clutch mechanisms, the fluid control system configured to allow the one or more clutch mechanisms to move from the engaged state to the disengaged state based upon sensing movement of the pipe relative to the tubular housing.

A drive shaft assembly for a down hole drilling motor is provided. The drive shaft assembly includes a drive shaft having a first end portion engaging a first housing and a second end portion, engaging a second housing. The first end portion and the first housing form the first constant velocity joint and the second end portion and the second housing form the second constant velocity joint of the drive shaft assembly. Each end portion including a base surface having a pair of prongs extending away from the base surface and a cylindrical side wall having a plurality of ball bearings held in a plurality of circumferentially spaced pockets. Each housing includes a cavity to retain respective end portions of the drive shaft. An inner side wall of each housing includes a plurality of cylindrical grooves to receive the plurality of ball bearings to transfer torque. An internal wall of the housing includes a first chamber and a second chamber to receive and retain the first prong and the second prong to transfer torque and thrust loads between the shaft and the housings.

A drive shaft assembly for a down hole drilling motor is provided. The drive shaft assembly includes a drive shaft having a first end portion engaging a first housing and a second end portion, engaging a second housing. The first end portion and the first housing form the first constant velocity joint and the second end portion and the second housing form the second constant velocity joint of the drive shaft assembly. Each end portion including a base surface having a pair of prongs extending away from the base surface and a cylindrical side wall having a plurality of ball bearings held in a plurality of circumferentially spaced pockets. Each housing includes a cavity to retain respective end portions of the drive shaft. An inner side wall of each housing includes a plurality of cylindrical grooves to receive the plurality of ball bearings to transfer torque. An internal wall of the housing includes a first chamber and a second chamber to receive and retain the first prong and the second prong to transfer torque and thrust loads between the shaft and the housings.

A universal joint assembled in a drill string transfers torque between two shafts where the shafts are not completely aligned. The universal joint includes a cable that passes through joint components. The cable limits separation or deflection of the joint components.

A connection assembly and a method comprises first and second connector portions having a preload mechanism comprising a plurality of bores and threaded fixings circumferentially spaced around the axis, wherein the preload mechanism is arranged to apply an axial load between shoulders on the first and second connector portions when torque is applied to the threaded fixings. An annular sealing member is compressed between the first and second portions, and the axial load applied between the first and second shoulders by the preload mechanism exceeds a peak hydrodynamic load urging the first and second connector portions in a direction along the axis. The axial force applied by the preload mechanism advantageously reduces the fatigue damage experienced by the connection, for example, by cyclic pressure changes within the connector portions typically caused by pumps operating at high pressures.

An apparatus comprises a first number of splines located near a first end of a first joint section and a second number of splines located near a second end of a second joint section. The first number of splines extends in an axial direction of the first joint section and spans a circumferential surface of the first joint section. Each of the first number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip and forms an acute angle. Each of the first number of splines are configured to be received between adjacent pairs of splines in the second number of splines as the first end of the first joint section and the second end of the second joint section are joined.

An apparatus comprises a first number of splines located near a first end of a first joint section and a second number of splines located near a second end of a second joint section. The first number of splines extends in an axial direction of the first joint section and spans a circumferential surface of the first joint section. Each of the first number of splines has a base, a tip, and a pair of flanks that extends from the base to the tip and forms an acute angle. Each of the first number of splines are configured to be received between adjacent pairs of splines in the second number of splines as the first end of the first joint section and the second end of the second joint section are joined.

One illustrative method disclosed herein includes positioning a first tubular adjacent a second tubular, wherein one of the first and second tubulars includes a plurality of radially deflectable fingers formed in an end thereof, mating the first and second tubulars into mated engagement with one another, wherein, during the mating of the first and second tubulars, the radially deflectable fingers deflect in a radial direction, and expanding the first and second tubulars by forcing an expansion mandrel through the mated first and second tubulars such that the expanded first and second tubulars have an expanded inside diameter that is greater than an initial inside diameter of the first and second tubulars.