METHOD OF DETERMINATION OF ROCK-CUTTING TOOL SERVICEABILITY Russian patent published in 2002 - IPC

FIELD: control of well drilling parameters; applicable in diagnostication of state of rock-cutting tools. SUBSTANCE: method includes measurement of pressure fluctuations of drilling mud onto drilling bit and variation of axial bit load, selection of actual criteria of serviceability, setting of their reference values and determination of serviceability of rock-cutting tool by comparison of criteria actual values with their reference values. Novelty consists in that Jeany coefficient Gp of pressure fluctuation of drilling mud and Jeany coefficient G_Q of variation of axial load are determined at any moment of drilling. Serviceability criteria are taken in the form of actual values Tp = 1 and T_Q = 1 = G_Q, In this case, minimal wear of rock-cutting tool, and, respectively, its maximum serviceability corresponding to maximum values of these criteria. Reference values of criteria are used in the form of TrefP