HIGH-FREQUENCY EXCITATIONS OF DRILLSTRING UNDER THE CONDITIONS OF PERIODIC ROCK DESTRUCTION. SELF-EXCITED OSCILLATOR
V.N. Dorovsky, S.V. Dorovsky
Siberian Software Company, ul. Moskovskaya 93, Novosibirsk, 630008, Russia
Keywords: High-frequency excitement, PDC bits, rock destruction
Abstract
The self-excited oscillator describing high-frequency excitations of a drillstring with high amplitudes of torsional oscillations has been presented. The self-excited oscillator is characterized by discrete degrees of freedom. Fundamentally, the work of the self-excited oscillator is based on the idea of the maximum cutting force during the destruction of rock by PDC bits and the results of laboratory studies by M.I. Vorozhtsov, K.I. Borisov, G.P. Cherepanov. The differential equations of the non-autonomous self-excited oscillator are based on the results of laboratory studies. A typical dynamic mode of the self-excited oscillator operation has been presented. The results have been compared with experimental data.
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