JOB SAFETY ANALYSIS OF A TOP DRIVE MACHINE IN MOBILE OFFSHORE DRILLING UNITS

摘要

Mobile Offshore Drilling Units (MODUs) are in charge of drilling operations at offshore environment. A derrick system, which handles drill pipes, risers, casing, blowout preventer, etc., and delivers such equipment to subsea is one of most important part in MODUs. Among the derrick system equipment, a top drive machine is regarded as the most dangerous because of the unexpected swinging movement of a tope drive machine by large wave. As a top drive machine is heavy and large, this swinging movement can lead workers to injuries or fatality. In this regards, this study aims to identify risky tasks related to a top drive machine during its maintenance and to suggest risk reducing measures by conducting a Job Safety Analysis. We categorized the maintenance tasks depending on the six top drive machine equipment and analysed their hazards and consequences. Among these tasks, maintenance of the weight compensating system was judged to be the most dangerous job, and measures to reduce the risk were proposed. The results of this study could be used to lower the risk of future drilling work.