DOWNHOLE DEVICE DELIVERY AND ASSOCIATED DRIVE TRANSFER SYSTEM AND METHOD OF DELIVERING A DEVICE DOWN A HOLE

A downhole device delivery and drive transfer system includes a sub which is arranged to attach to a drill string and a tool which is configured to enable it to travel through the drill string and releasably couple to the sub. The sub and the tool are arranged so that when they are releasably coupled to each other torque imparted to the drill string is transferred by the sub to the tool. The tool is arranged to carry one or more devices for performing one or more downhole functions such as core drilling, hole reaming or wedge placement for directional drilling. The system also has a guide mechanism that operates between the sub and the tool to guide the tool to a known rotational orientation relative to the sub as the tool travels into the sub. A fluid control system controls the flow of fluid through the tool through a downhole outlet and a plurality of ports intermediate opposite ends of the tool.