Semi-Active Hydropneumatic Heave Compensator

Abstract

A hydropneumatic heave compensation system and a semi-active control are proposed according to the requirements drilling offshore of 6 km deep. The goal of this semi-active control is to maintain an acceptable performance of the system when the drill string mass changes, which also changes the performance of the hydropneumatic system. The control action is executed just by a servo valve, which modifies the system damping to optimize the compensator performance. This servo valve is the only moving part of the control system and therefore, this system is more robust regarding mechanical/ electrical failures and it has low consumption energy. The results show a satisfactory frequency response of semi-active control when the drill string mass is changed.

Modelagem e controle de heave em coluna de perfuração

“…O aumento da massa suportada (coluna de perfuração) acarreta na compressão do gás do acumulador, ou seja, a rigidez da "mola equivelente"aumenta. Dessa forma, o compensador hidropneumático confere ao sistema uma menor variação da frequência natural quando a massa é alterada, apesar da rigidez equivalente da mola ser não linear com relação a massa Cuellar and Fortaleza (2014) e Cuellar and Fortaleza (2015) .…”