Abstract: A gap sub uses a plurality of insulating members in conjunction with at least two metallic members to effect a mechanically and electrically robust configuration. The gap sub includes an upper end portion, a lower end portion, an outer sleeve, an inner sleeve, an insulating outer washer, an insulating inner washer, and an insulating spider. The insulating outer washer is configured to transfer a first axial load between the upper end portion and the outer sleeve. The insulating inner washer is configured to transfer a second axial load between the inner sleeve and the lower end portion. The insulating spider is configured to transfer a torsional load between outer sleeve and the inner sleeve.

Abstract: A gap sub uses a plurality of insulating members in conjunction with at least two metallic members to effect a mechanically and electrically robust configuration. The gap sub includes an upper end portion, a lower end portion, an outer sleeve, an inner sleeve, an insulating outer washer, an insulating inner washer, and an insulating spider. The insulating outer washer is configured to transfer a first axial load between the upper end portion and the outer sleeve. The insulating inner washer is configured to transfer a second axial load between the inner sleeve and the lower end portion. The insulating spider is configured to transfer a torsional load between outer sleeve and the inner sleeve.

Abstract: A gap sub uses a plurality of insulating members in conjunction with at least two metallic members to effect a mechanically and electrically robust configuration. The gap sub includes an upper end portion, a lower end portion, an outer sleeve, an inner sleeve, an insulating outer washer, an insulating inner washer, and an insulating spider. The insulating outer washer is configured to transfer a first axial load between the upper end portion and the outer sleeve. The insulating inner washer is configured to transfer a second axial load between the inner sleeve and the lower end portion. The insulating spider is configured to transfer a torsional load between outer sleeve and the inner sleeve.

Abstract: A data transmission system for use with a drill string in a primary wellbore is disclosed. The data transmission system includes a toroidal antenna assembly. The toroidal antenna assembly is disposed around the drill string at a primary downhole location within the primary wellbore and configured to transmit a signal from a transmitter. The signal corresponds to sensor data. The toroidal antenna assembly includes a plurality of toroidal antennas, wherein each toroidal antenna is configured to transmit the same signal from the transmitter. Because a plurality of toroidal antennas are utilized to transmit the same signal, construction of the drill string can be more mechanically robust than a conventional insulated gap collar while permitting reliable and fast transmission of sensor data to the surface.

Abstract: A gap sub uses a plurality of insulating members in conjunction with at least two metallic members to effect a mechanically and electrically robust configuration. The gap sub includes an upper end portion, a lower end portion, an outer sleeve, an inner sleeve, an insulating outer washer, an insulating inner washer, and an insulating spider. The insulating outer washer is configured to transfer a first axial load between the upper end portion and the outer sleeve. The insulating inner washer is configured to transfer a second axial load between the inner sleeve and the lower end portion. The insulating spider is configured to transfer a torsional load between outer sleeve and the inner sleeve.

Abstract: A dynamically controllable variable displacement axial piston pump is described. In an embodiment, the pump comprises a rotating cylinder with hydraulic pistons that contact the face of a swash plate. The angle of the swash plate can be controlled to thereby control the movement of the pistons, the displacement of the pump, and the power generated by the pump. The dynamically controllable variable displacement axial piston pump may be used in combination with a rotary steerable apparatus, including such an apparatus as described herein that uses hydraulic pistons to actuate the deflection of the bit, or in combination with other downhole tools and devices. When used down hole in a drill string with a drilling mud powered turbine, the dynamically controllable variable displacement pump limits and regulates the power provided to the tool over a wide range of drilling mud weights and flow rates.