IMPACT OF DRILL STRING BEATS ON THE RATE OF PENETRATION

摘要

On the mechanical rate of penetration is influenced by a number of factors, one of the main factors is the factor due to severe beatings of the drill string. Data on the effect of the beats on the mechanical rate of penetration is extremely contradictory and not sufficiently clarify the depth of the issue. Authors besides theoretical assumptions the results of experimental work that allows you to not only explain the emergence and influence of the beats in the drilling process, but also give recommendations for their compensation.It is clarified that when the critical depth of penetration and at a sufficient axial load may be a loss of form stability of the drill string, which leads to the appearance of flexural half waves and the result is hard to beat. The analysis of power costs and accounting for experimental data to determine the reduction of the torque on the drilling tool based on the beat, and with a corresponding decrease in the rate of penetration.Analysis dissipative forces depending on the increase in weight on bit and rotational angular velocity. The analysis of power costs usually do not include the cost of the rotation of the column at a heartbeat. Using the experimental data allowed to determine the component of the cost of power.The change in torque on the drilling tool with a decrease in power as a result of the beating. Reducing the torque determines the decrease in the axial load on the drilling tool. The numerical calculation of reducing the axial load under the influence of the beat, which allowed to find the numerical values of the specific thrust before the beat and after their occurrence.Based on functional dependencies ROP well on the specific axial load determined the effect of the beats on the mechanical speed.