Anordning for alternerende kjerneboring og boring av en underjordisk formasjon

摘要

A core barrel having an inner tube for coring and, alternately, a center plug assembly or closing the throat of the core bit at the bottom of the assembly for drilling in lieu of coring. The inner tube assembly and plug assembly are disposable and retrievable through the drill string on a wireline using an overshot. The core bit is of a stabilized, preferably anti-whirl, design and may be a low-invasion core bit used in cooperation with a low-invasion coring shoe. A logging tool and data transmission assembly may be incorporated in the plug assembly for logging while drilling.