| 摘要 |
FIELD: well drilling. SUBSTANCE: drilling tool having the first part on which drill bit is mounted, and the second part carrying electric motor with joint coupling between them. Curved section with small curvature radius is completed with the use of drilling tool with joint coupling deflecting to the first side of wellbore to direct the drill bit to the other side. Upon completion of curved section, drilling is carried out in strictly straight direction by installation of eccentric coupling which is secured to drilling tool in the point near joint link. Eccentric coupling keeps drilling tool at a small angle, less than that in drilling curved section. Simultaneously with rotation of drill bit, drill string, tool and coupling rotate slower round longitudinal axis in order to continuously vary the strinking angle of drill bit. In some other version of design, before attachment of eccentric coupling, cylindrical or concentric coupling is attached for drilling the first short length of horizontal section. In an alternative version, the design of the eccentric coupling has two flat sides which provide for rotation of coupling and drilling tool in slightly curved wellbore without seizing. EFFECT: higher efficiency. 26 cl, 9 dwg |
