Development of bits for directional drilling in complex mining and geological conditions

The purpose of the study is to improve the efficiency of directional drilling using continuous whipstocks in difficult mining and geological conditions. The research involves the description of mining and geological conditions featuring decreased efficiency of continuous whipstock operation as well as the reasons why the decrease is observed. It should be noted that significant problems arise when using the milling-type continuous whipstocks for sidetracking in hard rocks from the plug back total depths of cement mixtures and well deviations in the intervals of normal face weakened rocks. In this case, there is a decrease in deviation accuracy, due to the increased sinking speed that prevents curvature accumulation and which is difficult to control by the drilling mode parameters. Another problem that decreases the well deviation accuracy when using milling-type whipstocks in hard rocks is the deviation of the drift angle build up plane due to the disorienting force that occurs during milling of the borehole wall. The study briefly dwells upon the existing technologies and engineering means, the use of which is aimed at improving the whipstock performance in complex mining and geological conditions, including through the use of bits with a special design. The author has proposed and patented a series of new technical means (bits) and technological solutions that effectively deal with the drop in the performance of continuous whipstocks in the well deviated in hard rocks. Moreover, the developed means took into account the shortcomings of current technical equipment.

wellbore deviation, plug back total depth, whipstock, rock, bit