ADJUSTABLE DEVICE FOR DIRECTIONAL WELL DRILLING Russian patent published in 2006 - IPC E21B7/08 

FIELD: drilling equipment, particularly to drill controlled directional and horizontal wells.

SUBSTANCE: device comprises bent nipple with sealing means and adjusting and coupling conical threads formed on ends thereof. Installed on bent nipple is distance bushing having right and oblique thrust ends, wherein the oblique end is inclined at α° angle. Arranged on adjusting thread is bent sub with inlet thread. Connected to coupling thread is straight sub with outlet thread. The distance bushing, bent sub and straight sub have flat outer thrust ends, cooperate with each other by the thrust ends and may be displaced in axial direction by means of sliding keys. Mating parts of adjusting and coupling conical threads are press-fitted. Central axes if bent nipple and bent sub threads intersect at α° angle. Device has adjusting thrust rings fitted in subs to set guaranteed device deviation angle variation limits and to perform periodic cooperation with thrust ends of bent sub at threshold device deviation angles. Plane of distance bushing symmetry is aligned with plane of bent nipple curvature. Bent nipple may be formed by radial displacement and rotation through α° angle of central coupling conical thread axis relatively central bent nipple axis. Magnitude of radial displacement of central coupling conical thread axis is in direct proportion to axial distance bushing length and to tangent of angle α°, which is angle of mutual adjusting and coupling thread axes inclination. At maximal device deviation angle planes of bent nipple and bent sub curvatures and points of central thread axes thereof intersection are aligned one with another, adjusting conical thread provides press-fitting with maximal admissible interference, thrust end of bent sub is tightly pressed against adjusting thrust ring installed in bent sub. At zero device deviation angle extensions of central axes of inlet bent sub thread and coupling conical thread of bent nipple coincide, coupling conical thread is press-fitted with maximal interference, thrust end of bent nipple is tightly pressed to adjusting thrust ring installed in straight sub. Summary gap between bent nipple ends and free ends of adjusting thrust rings installed in subs is not more than half of adjusting conical thread pitch. Inner collars with end teeth engaging each other are additionally formed on adjacent ends of distance bushing.

EFFECT: increased accuracy of well drilling due to elimination of uncontrolled device deviation in two different planes.

5 cl, 4 dwg