A casing string includes an uphole section, a downhole section, and a sealed chamber that is fluidically isolated from the uphole and downhole sections. The sealed chamber extends between the uphole and downhole sections. The casing string further includes a tube that is disposed within the sealed chamber and that fluidically connects the uphole and downhole sections to provide a fluid flow path that extends past the sealed chamber and through the casing string.

A casing string includes an uphole section, a downhole section, and a sealed chamber that is fluidically isolated from the uphole and downhole sections. The sealed chamber extends between the uphole and downhole sections. The casing string further includes a tube that is disposed within the sealed chamber and that fluidically connects the uphole and downhole sections to provide a fluid flow path that extends past the sealed chamber and through the casing string.

A retention system for attaching a collar to a pipe. The collar has an internally-disposed groove configured for placement of a ring. The ring is sized such that in one orientation, it can enter the collar between torque-transmitting features into the internally-disposed groove. Once in the groove, the ring may be adjusted such that its aperture is generally aligned with the axis of the collar. In this orientation, the features retain the ring within the groove. A bolt and a pipe may then be placed within the collar from opposite sides. The bolt is attached to the pipe through the ring. Once joined, the collar is joined to the pipe, forming its box end. Such a retention system may be used to join a series of inner pipe members of a dual-member pipe assembly, as in horizontal directional drilling.

A retention system for attaching a collar to a pipe. The collar has an internally-disposed groove configured for placement of a ring. The ring is sized such that in one orientation, it can enter the collar between torque-transmitting features into the internally-disposed groove. Once in the groove, the ring may be adjusted such that its aperture is generally aligned with the axis of the collar. In this orientation, the features retain the ring within the groove. A bolt and a pipe may then be placed within the collar from opposite sides. The bolt is attached to the pipe through the ring. Once joined, the collar is joined to the pipe, forming its box end. Such a retention system may be used to join a series of inner pipe members of a dual-member pipe assembly, as in horizontal directional drilling.

A tubular string includes a first tubular member with a pin end with pin threads and a pin external load shoulder. The tubular string also includes a second tubular member with a box end with a box external load shoulder and box threads, the pin threads being threadable into the box threads to form a connection, wherein the pin external load shoulder has an outer diameter (OD) that is different than an OD of the box external load shoulder. A load distribution sleeve is locatable between the first and second tubular members when threaded together and includes a first end facing the first tubular member and a second end facing the second tubular member, wherein the ODs of the load distribution sleeve first and second ends match the ODs of the pin and box external load shoulders respectively. The load distribution sleeve contacts the pin and box external load shoulders and distributes a make-up load between the pin and box external load shoulders when the connection is made up.

A tubular string includes a first tubular member with a pin end with pin threads and a pin external load shoulder. The tubular string also includes a second tubular member with a box end with a box external load shoulder and box threads, the pin threads being threadable into the box threads to form a connection, wherein the pin external load shoulder has an outer diameter (OD) that is different than an OD of the box external load shoulder. A load distribution sleeve is locatable between the first and second tubular members when threaded together and includes a first end facing the first tubular member and a second end facing the second tubular member, wherein the ODs of the load distribution sleeve first and second ends match the ODs of the pin and box external load shoulders respectively. The load distribution sleeve contacts the pin and box external load shoulders and distributes a make-up load between the pin and box external load shoulders when the connection is made up.

A logging-while-drilling (LWD) tool for use within a formation. The LWD tool may include a transmitter, a receiver, and an acoustic isolator. The transmitter may be operable to transmit an acoustic signal into the formation. The receiver may be operable to receive an acoustic response from the formation. The acoustic isolator may be positioned longitudinally between the transmitter and the receiver to reduce a transfer of acoustic energy between the transmitter and the receiver through the LWD tool. The acoustic isolator may include annular chambers formed in a body of the acoustic isolator and positioned along a longitudinal axis of the acoustic isolator.

A logging-while-drilling (LWD) tool for use within a formation. The LWD tool may include a transmitter, a receiver, and an acoustic isolator. The transmitter may be operable to transmit an acoustic signal into the formation. The receiver may be operable to receive an acoustic response from the formation. The acoustic isolator may be positioned longitudinally between the transmitter and the receiver to reduce a transfer of acoustic energy between the transmitter and the receiver through the LWD tool. The acoustic isolator may include annular chambers formed in a body of the acoustic isolator and positioned along a longitudinal axis of the acoustic isolator.

An interference apparatus is provided for a motor shaft transmission assembly. The interference apparatus may include split-ring shells and a retaining device. The interference apparatus may be mounted to an intermediate sleeve of the motor shaft transmission assembly. The interference apparatus is configured to prevent the loss of certain motor shaft transmission assembly components downhole in the event of a failure of the motor transmission due to dynamic loads.

Rotary steerable drilling apparatus and methods utilizing apparatus comprising a shaft, a multi-angle strike ring axially repositionable along the shaft, an articulated member coupled to the shaft, and a steering member carried by the articulated member. An actuator is operable to maintain an angular offset of the articulated member relative to the shaft by maintaining azimuthally-dependent contact between the multi-angle strike ring and the steering member.