Improving the technique for assessing the condition and predicting the wear of the rock destruction tool equipment

Abstract

To ensure the trouble-free operation of the rock-destroying tool, the peculiarities of its interaction with the rock at different stages of work must be additionally studied. Still unexplored in full is the relationship between the state of the equipment of the rock-destroying tool and the oscillatory processes during the operation of the drilling tool. The basic dependences for determining the wear indicators of the equipment of the rock-destroying tool have been proposed. The scheme for implementing the method of assessing the condition and predicting the wear of equipment, taking into account the peculiarities of its interaction with the rock, has been improved. Underlying its implementation is the presence of a law of change of at least one generalized coordinate of an arbitrary cross-section of a drilling tool. Bench experimental studies were carried out, according to the results of which the dependence of the depth of the face deepening on the mode parameters of drilling and the geometry of the equipment was established. It was found that the wear of the cutter by 1 mm causes a decrease in the amplitude of longitudinal oscillations by an average of 1.4 times. The obtained functions of deepening the face were used to determine the energy indicators of the process of rock destruction. Given the peculiarities of the implementation of the experiment, the work and power of the axial load for the destruction of the rocks of the pit were used for such indicators. It should also be noted that the construction of numerical models is necessary for a complete assessment and prediction of the wear of rock-destructive tools. They should reflect the mechanical system and provide the ability to obtain the values of parameters that are not determined by the results of a laboratory experiment.

An Analytical–Numerical Model for Determining “Drill String–Wellbore” Frictional Interaction Forces

“…For this type of drilling, the well axis is a spatial curve; therefore, the drill string is a complex system with distributed parameters. Depending on the external loads and the "drill string-well bore" contact interaction conditions, sections of the drill string have a spiral shape, with local losses of stability, which perform various kinds of oscillations [4][5][6][7][8]. At the same time, the drill string is exposed to frictional and contact forces, inertial forces of the washing fluid, etc.…”

“…At the same time, the drill string is exposed to frictional and contact forces, inertial forces of the washing fluid, etc. These phenomena inflict harm on drilling tools and downhole engines' performance, generally leading to non-productive energy losses and deterioration of technical and economic indicators of drilling [6,8]. The drilling efficiency of modern, widely used technologies is not too high.…”