Patent ID: 6702042
Filing Date: 2004-03-09
Classification: E21B

Abstract:
A rotary well drilling method, comprising the following successive phases:introducing into a pre-drilled part of a well (16) a drilling system comprised of a drill bit (11) assembled with tubular string elements (15), means for measuring the inclination and azimuth direction of the pre-drilled part of the well, means for rotary friction (26, 27) against the wall of said pre-drilled part and controlled means capable of modifying the friction coefficient of said means for friction against the wall; measuring the azimuth direction of the pre-drilled part of the well (16); and varying sufficiently the friction coefficient of said means for friction (26, 27) to influence the azimuth direction of the next part of the well to be drilled, wherein the means for rotary friction comprise a stabilizing element with a variable geometry (26, 27), free-mounted in rotation in relation to the string (15), and controlled connection means in rotation of said stabilizing element with the string (15).