Offset drilling of straight, deviated or curved bores for gas or oil

摘要

Drilling a borehole with a small radius curved section, and essentially straight section at one end, comprises using (a) a drill string, with drilling fluid supplied to the rear, (b) an articulated boring tool with an oblong body, consisting of a first and second tool section, including a motor to provide the required drive, and a drill bit on the front end of the first section, which rotates relative to the body, setting up the reaction torque, through which the drilling fluid is pumped, and (c) a linking device, between the first and second tool sections, fixed on an axis at right angles to the long axis of the tool body, so that the first tool section carrying the bit, can swing relative to the mutual straight line axis of the two sections. A boring tool and linking device to carry out the described procedure, are also claimed.