engleski

Modeling of drill-string drives for rotational and longitudinal motion during vertical drilling

The oil drilling process is characterized by notable compliance due to finite stiffness of individual drill-string drive components such as drill-pipes and draw-works-based hoisting system, and friction due to tool vs. rock bed and drill-string vs. borehole interactions. Moreover, for the correct operation of the overall drilling process, the individual piston-pump drives within the mud pump system need to be precisely coordinated in order to prevent the occurrence of high-magnitude mud pressure pulsations due to individual piston strokes. Hence, in order to develop high-performance control systems capable of suppressing the emergence of compliance and friction-related vibrations in both drill-string rotary and longitudinal motion control systems, and piston-action related mud pressure pulsations, it is paramount to derive reasonably-detailed models of the rotary and longitudinal drill-string drives, and the mud-pump system. These models should include models of prime movers (electrical drives) and transmission system, as well as the mass-damper-spring model of the drill-string, and the mud pump system pressure vs. flow dynamic relationships. Finally, the tool vs. rock bed and drill-string vs. borehole interaction should be modeled by a suitable friction model in the case of drilling system.

Modeling ; drill-string electrical drive ; hoist winch electrical drive ; vertical drilling

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