Hole completion technology for high level directional long borehole in complex roof

Abstract

Aiming at the problems existing in the construction of high directional drilling in Tingnan Coal Mine roof, such as stratum breakage in open hole section, mudstone shrinkage in directional hole section, low efficiency of two-stage reaming and easy plugging of extraction channel after hole formation, the drilling and completion technology of high directional long hole in complex roof was proposed. The key technologies such as large-diameter casing hole protection, shrinking neck formation hole reaming, two-stage two-speed one-shot hole reaming and steel screen hole completion were integrated. The high power directional drilling rig, mud pump truck, measurement while drilling device, hydraulic screw drilling tool and double stage and double speed expanding screw drilling tool were equipped. The field application was carried out in the drilling field of 3410 working face of Tingnan Coal Mine. Two directional holes at the top of the roof were constructed, with the hole depth of 511 m and 610 m respectively, and the diameter of the hole was 200 mm. The diameter of the single shift was more than 60 m, and the 89 mm steel screen with hole protection was inserted into the whole hole. The drilling process was safe and efficient, which can provide a new technical way for the construction of high directional long borehole in complex roof.

Keywords

• complex roof
• high level borehole
• casing protection
• one-shot reaming
• screen hole completion