Core drilling tool for boreholes in rock

摘要

A core drilling tool for bore-holes includes a stem for connection to the string and an outer rotating tube for rotating a drill bit mounted thereon. A core tube is mounted in a central passage by a latch means to remove the core tube and/or replace it. The outer tube is rotated by a downhole motor such as a Moineau type motor. The diameter of the central passage through the stator is equal to the maximum diameter of the core tube plus the eccentricity of the stator to permit passage of the core tube into and out of the tool. Thus coring can be achieved without tripping the tool. Various details of the structure are described.