Studying the Performance Features of Drilling Rock Destruction and Technological Tools

Abstract

The principal results of studying the performance mechanism of drilling bits with a modernized cutting and bottomhole assembly system were compared. An engineering method of calculating the minimum axial load required for highly efficient bulk destruction was formulated. The existence of stable relation between the possible penetration depth of a single drilling rock destruction tool and the implemented rotation speed at a certain maintained axial load was proven. Rational parameters were determined for the drilling regime of bits of 112 and 132 mm in diameter. A method of arranging the cutting structure on the roller of a bit was proposed to provide a 50–100-% increase in the mechanical velocity in every certain case. Based on the measured speeds per run in drilling with the proposed bits, the repeated destruction of separated bottomhole particles beneath the roller of a bit was revealed to be prevented to a certain extent to essentially increase the service life of the tool. The destruction conditions were established to become more favorable under the hydrostatic pressure of a flushing liquid column in the case when the bits with the modernized cutting structure were applied. The application of special lubricating impurities for the chemical treatment of drilling slurries was shown to provide a 2–3-fold decrease in the drillstring rotation power in the average. In addition to the control over the lubricating capability of drilling slurries, the active impurities were revealed to have a positive effect on the viscosity and static shear stress values to be recommendable for use in drilling the rocks prone to intensive absorption and drilling slurry formation.