Light-Alloy Drill Pipes for Diamond Drilling.

It has been established by acceptance tests that the use of 55-mm-diam aluminum alloy drill pipes with nipple connections makes it possible to drill wells to a depth of 1200 m at a drilling machine speed of 780 rpm. In this case a high reliability of the column is achieved in naturally curved wells up to 6 degree at 100 m, and in the case of artificial curvature up to 10 at 1 m. An increase in the mechanical (13-32%) and technical (15-34%) drilling speeds is achieved, as well as an increase in the depth per pass (6-13%) and a decrease in the time required for lowering and raising operations (11-15%).