Submitted by Wood Group
Inclement weather, intermittent accessibility and poor control of environment are well recognised factors that negatively affect schedule and drive up costs for planned and unplanned activities. Looking beyond traditionally accepted access solutions, which tend to be inflexible, slow to set up and difficult to move, we have achieved significant cost savings by adopting flexible access solutions.
The most important aspect of access solutions is ensuring the continuous safety of workers. By seeking an optimised approach to each situation we are able to ensure safety, maximise tool time, and assure greater integrity and reliability of delivery by creating a consistent environment. Across the range of access options this can deliver anything from simple gains on worksite efficiencies through to negating a shutdown.
By challenging conventional approaches to access solutions we were able to ensure significant savings on material cost, improved safety and increased tool time.
Description of Best Practice
In deciding upon an access solution Wood Group considers the following aspects;
- Environment of work area – potential for hydrocarbon release, is a shutdown required?
- Nature of the work – hot work vs inspection
- Work at height – can this be avoided?
- Workface planning
- Area covered – does the solution need to be flexible?
Case 1: Safezone positive pressure habitats allow hot work and hazardous area operations to take place with fewer isolations and the possibility to avoid an asset shutdown. This system is modular in design and can be modified to accommodate a wide range of works. The system was originally available in the UKCS via one supplier, increasing the likelihood of bottlenecks in deployment and intermittent availability. In 2016 Wood Group purchased 5 systems, with a further 5 currently on order, to ensure that we can deploy the system on our clients’ assets whenever a requirement arises. Including this technology in our in-house suite of services streamlines the delivery and use of the system.
Case 2: In order to assess the integrity of clamped saddle support locations on a gas terminal slug catcher, a specialist vendor required access arrangements and weather protection. A total of 143 pipe supports needed to be inspected over a wide area, meaning that a conventional rolling roof was not suitable. Wood Group considered a range of new solutions to reduce work at height risk, improve productivity, and contain both labour and scaffold hire costs. Ultimately, we selected an aviation industry quality inflatable habitat combined with a rolling scaffold system for this application. Adopting lean access and alternative industry technologies contributed to an 85% saving on the original inspection budget.
Case 3: The strengthening of a congested pipe deck required both a highly controlled environment to ensure the correct bonding of new plates, and the ability to maneuver quickly around changing drilling operations. To overcome the erecting and dismantling of the scaffold we designed a mono-flex sheeted scaffold that can be lifted by the crane and moved into location. This removes the need to carry out multiple erection and dismantling, reducing the risks of carrying out multiple operations on a busy pipe deck and reducing costs.
Case 4: In 2012 we deployed the first remote operated aerial vehicle (ROAV) for offshore use in the UKCS. A typical detailed structural and coating inspection of the drilling derrick would have required the facilities to be taken out of commission for around three weeks. Additionally, to review the condition of the platform under deck would have required considerable under scaffolding and over side work with appropriate supply vessel support. The ROAV was able to carry out the derrick inspection whilst well plug and abandon (P&A) activity continued, avoiding an estimated 3 week shut down and saving around £1,680,000. More importantly, it eliminated the need for four inspectors to carry out the work, which would have required significant use of rope access, thereby virtually eliminating the risk. The use of the ROAV for the under decking review avoided the need for under deck scaffolding and rope access at an estimated cost of £121,000. The ROAV scope of work cost £71,000, providing a saving of £50,000. Finally the use of the ROAV negated the need for over side working and standby vessels for support.
Contact: Philip Oliver