EMERGENCY TOOL FOR EXTRACTION OF STUCK DRILL STRING IN INCLINED-DIRECTED WELL Russian patent published in 2020 - IPC E21B31/00 E21B23/00 E21B7/28 

FIELD: mining.

SUBSTANCE: invention relates to the field of drilling equipment and is intended for extraction of the stuck drill string and the drilling tool in directional and horizontal wells. Tool comprises parallel-coupled drill string with bore and jet head, which is connected coaxially with guide sleeve, which can slide on stuck drill string. Guide bushing is equipped with an annular bit and is connected by means of gear transmission with parallel-coupled drill string. To ensure stability of well drilling in a given direction, it is necessary that ratio of moments created at drilling and annular crowns M₁ and M_2, respectively, is proportional to the ratio of drilling area of these crowns S₁ and S₂. Dynamic balance of the system (drill string) is achieved by performing a gear ratio i₂₁:S₁/S₂ = M₁/M₂ = z₁/z₂ = i₂₁, where z₁ and z₂ is the number of teeth of the gears of the gear train from the drilling and from annular crowns respectively.

EFFECT: improving release reliability of stuck string.

1 cl, 2 dwg