DNV GL issues guidance on jacking gear

Corroded jacking gear Corroded jacking gear DNV GL

SEPTEMBER 26, 2014—Jack-up rig safety can be severely compromised by jacking gear failure. An incident in which a rig tilted in a Singapore shipyard last year injured 90 workers. In that incident, a failure of a braking system element was implicated, however other factors in jacking gear failure can be maintenance related.

A joint industry project on jacking system maintenance and inspection has resulted in a new DNV GL Recommended Practice. This provides guidance to ensure the correct and safe functioning of rack and pinion style jacking systems. The objective is to reduce the risk of gear failure, resulting in lower costs and higher availability throughout the asset's life time.

The consequences of jacking gear failure can be severe and, while the problem is acknowledged by the industry, the correct maintenance and inspection of the jacking systems have proven to be challenging due to the high turnover of people with specific knowledge on board, the evolving nature of the systems, and the intermittent use of the systems.

To come up with practical guidance for the jack-up industry, DNV GL has been collaborating in a Joint Industry Project (JIP) with the drilling contractors Rowan Drilling, Seadrill, Prospector Drilling, Noble Drilling and UAE's National Drilling Company, the recently merged service suppliers Energy Service International, WillTeco, and vendor Cameron Letourneau .

"In bringing together key industry players, the JIP format provided the opportunity to openly discuss issues and challenges related to jacking gears. The recommendations from this collaboration will help to reduce the risk of jacking gear failure, downtime and the overall life cycle cost," says Michiel van der Geest, Project Manager, DNV GL - Oil & Gas.

DNV GL will issue a recommended practice (RP) in October proposing the following measures:

  • Clear definitions of competency levels supporting the organisation of and knowledge transfer between the different roles involved in jacking system inspection and maintenance. This will also help the crew determine when to call for assistance and what they can do on their own.
  • Clear definitions of the inspections that can be executed by the onboard crew and what should be covered in periodical surveys by experts. Specific recommendations are given for inspections after operations close to or exceeding jacking system design limitations to (re-) gain confidence in the system and detect possible limitations.
  • Best practices for an effective maintenance organisation.
  • Clear guidance on what information the operators and original equipment manufacturers (OEMs) need to provide in the form of user and maintenance records. Very specific information is needed for correct system assessment and maintenance throughout the asset's lifetime.
  • A detailed overview of specific components, including a short description of their functionality and consequence of failure, typical observations and recommended follow-up actions.
  • Best practice for the selection of spares, with a specific focus on obsolescence issues to avoid unnecessary delays caused by logistics.
  • Based on Reliability, Availability and Maintainability (RAM) and Reliability Centered Maintenance (RCM) analyses, there are recommendations for further improvements related to maintenance and inspection. The possible improvements are demonstrated in a case study.

Following the publication of the RP, DNV GL, in cooperation with the other JIP partners, will arrange experience-exchange sessions and presentations of the RP in the major oil and gas industry hubs worldwide.

In addition, DNV GL is actively seeking input for the further development of the recommended practice in cooperation with other industry bodies.

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