METHOD OF DRILLING CONTROL Russian patent published in 1994 - IPC

FIELD: drilling of vertical wells. SUBSTANCE: in the course of drilling, upper end of drill pipe string is fixed to prevent longitudinal displacements and the value of axial load on the drill bit, torque, amplitude and natural frequency ν of bending oscillations of weighted bottom are measured. Axial loads P_i corresponding with extremes of parameters under measurement are determined. Working axial load P_p is determined by the formula P_p=0.5(P_i+P_i+1) or taken equal to P_i, speed of drill bit rotation being determined by the formula: , where k - quantity of rolling cutters of the drill bit. In this case operating conditions of the drill bit are improved at the expense of decrease in dynamic loads. Working axial load is applied periodically from P_i to 0.5(P_i+P_i+1) and vice versa. EFFECT: enhanced efficiency of drilling of vertical wells. 4 cl, 2 dwg