Development of Mathematical Model for Controlling the Drilling Parameters with a Screw Downhole Motor

Document Type: Original Article

Authors

1 PhD Candidate of Well Drilling Department, Oil and Gas Faculty, Saint-Petersburg Mining University

2 Head of Well Drilling Department, Saint Petersburg Mining University

3 Associate Professor of Well Drilling Department, Saint-Petersburg Mining University

4 Well Drilling Department, Saint-Petersburg Mining University

Abstract

Article presents results of study on possibility of increasing the efficiency of drilling directional straight sections of wells using screw downhole motors (SDM) with a combined method of drilling with rotation of drilling string (DS). Goal is to ensure steady-state operation of SDM with simultaneous rotation of DS by reducing the amplitude of oscillations with adjusting the parameters of drilling mode on the basis of mathematical modeling for SDM – DS system.
Results of experimental study on determination of extrema distribution of lateral and axial oscillations of SDM frame depending on geometrical parameters of gerotor mechanism and modes ensuring stable operation are presented.
Approaches to development of a mathematical model and methodology are conceptually outlined that allow determining the range of self-oscillations for SDM – DS system and boundaries of rotational and translational wave perturbations for a heterogeneous rod with an installed SDM at drilling directional straight sections of well. This mathematical model of SDM – DS system's dynamics makes it possible to predict optimal parameters of directional drilling mode that ensure stable operation of borehole assembly.

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