METHOD AND APPARATUS FOR RELAYING DOWNHOLE DATA TO THE SURFACE

摘要

An apparatus and method for the transmission of information between downhole and surface locations through a drillstring. The apparatus includes a wireline extending from instrumentation at the downhole location to a clamp-off sub in the drillstring where it is connected to the lower end of a cable spooled on a cable cartridge above the clampoff sub in the drillstring. The cable cartridge is moved upwardly through-successive pipe joints added to the drillstring as drilling progresses, to permit rotation of the drillstring and use of blowout preventors without retrieving the wireline or cable. Cartridge cable is releasably connected at its upper end to a wireline extending through a pack-off to a slip ring assembly at the surface, for transmitting data from downhole instrumentation to surface equipment. Multiple cable cartridges may be sequentially added in series if drilling proceeds beyond the length of cable in a single cartridge.