METHOD OF DETERMINING WORKING CAPACITY OF ROCK CUTTING TOOL Russian patent published in 2020 - IPC E21B45/00 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to control and measurement of parameters during drilling of oil and gas wells and can be mainly used in diagnosing serviceability of rock cutting tool for its effective development, as well as in development of automated drilling process control systems. Method of determining working capacity of rock cutting tool includes measuring fluctuations of pressure of flushing liquid on bit, selecting current operability criteria, setting their reference values and determining the operability of the rock cutting tool by comparing the current criteria values with their reference values. Additionally, oscillations of axial load are measured on bit by sensor installed on fixed end of melt cable or on hydraulic weight indicator, and determining the Hurst exponent H_Q of oscillations of the axial load at the beginning and during well spudding drilling. Another sensor mounted on the manifold line measures the flushing fluid pressure fluctuations and determines the Hurst exponent H_P of flushing fluid pressure variations and the current diagnostic criteria are K_XP= H_P2/H_P1 and K_XQ = H_Q2/H_Q1 of the corresponding signals, where H_P1 and H_Q1 are Hurst exponents according to flushing fluid pressure fluctuations and axial load oscillations at chisel start; H_P2 and H_Q2 are Hurst exponents, respectively, of flushing fluid pressure fluctuations and axial load during spudding drilling. Reference values of criteria are determined during drilling of the first well on the cluster for the most worn-out tool.

EFFECT: higher accuracy of assessment of technical condition of rock cutting tool during operation.

1 cl, 2 dwg, 3 tbl