Planning is crucial for any rig move and installation procedure; however, on-the-ground expertise is equally important when it comes to problem-solving on location. Differences in weather conditions, unexpected soil profiles and technical issues can all impact on the success of a rig moving or installation project. Here, the knowledge and expertise of an experienced tow master or marine warranty surveyor can make all the difference to both safety and cost.
“Every day that a rig is not operational costs its operator and the field operator money,” explained Captain Jonathan Mills, principal surveyor, Noble Denton marine assurance and advisory, DNV GL - Oil & Gas. “Our role is to draw on our experience and expertise to help customers avoid delays and ensure efficient and safe operations.” Typically, this includes supporting customers throughout the rig-moving process, from location suitability checks; rig related assurances, such as sea fastening and stability checks; approval of towing/anchor handling vessels; to the final rig emplacement at the new drilling location. But, it also involves recognizing and capitalizing on opportunities to complete projects more efficiently.
As an example, Mills gave a recent project in which he and his team were able to make use of favourable weather conditions to complete a move procedure earlier than scheduled. “The weather forecast had predicted adverse conditions for four to five days; however, conditions began improving earlier than expected,” he said. “We knew that the company’s internal rig-moving procedure stipulated a favourable three-day weather window, but there was also a target to get the rig onto the new location as soon as possible. By drawing on our prior knowledge of site-specific conditions, prevailing weather developments and master mariner’s expertise, we were able to assess the possibilities of moving in a two-day window, thereby cutting down non-production time.”
As the industry adapts to an era of low oil prices, cost factors are impacting on operator budgets for third-party marine warranty surveying, rig-moving and towmaster support. This can often lead to attempts to limit the involvement of third-party assurance and advisory services to the bare minimum; however, Mills believes that only by involving industry specialists at the very beginning of a rig-move project can companies introduce real cost-saving strategies.
“Involving specialists early on in a project allows operators to plan and budget more effectively, as opposed to bringing in external support at the last minute and discovering problems that need to be fixed,” he explained.
“The challenges facing any rig move project are relatively similar: adverse weather conditions, time constraints and inexperience among marine crews and/or support vessels when it comes to towing or anchor handling are all factors that need to be considered and overcome. Involving marine warranty surveyors and experienced towmasters in advance can help to achieve that, and facilitate the process once it is underway.”
Here, he said, technology could also play a key role. “Through our geotechnical support team and by making use of our in-house JUSTAS software, we are able to tackle complex site specific engineering challenges in real-time. This is particularly important during rig installation procedures, as it enables us to provide fast and reliable solutions to unexpected site conditions,” Mills said. “All we need is an internet connection to allow 24/7 access to the expertise onshore in the DNV GL office. For example, we can re-assess unexpected leg penetration behaviours, and develop alternative pre-load requirements and strategies to overcome the risk of leg hung-up and significant differential leg penetration issues.”
This ability to access data and expertise can make all the difference to project success and cost, as Mills explained: “We found that, during a recent rig emplacement operation, the asset’s leg penetration was in excess of the expected level. The installation operation had to be halted due to the associated risks. Our ability to transmit live data back to shore and to communicate directly with our jack-up and geotechnical experts, even late at night, enabled us to re-evaluate the soil conditions and continue the rig installation process without causing our customer costly delays.”
Leading the field
Innovation is a key area of focus for DNV GL in this respect. Its Noble Denton marine assurance and advisory service area pioneered the concept of marine warranty services in the 1960s, and has continued to focus on driving it forward ever since.
“Our prolonged exposure to the industry and knowledge of the challenges our customers face enable us to focus on developing solutions that meet their needs,” explained Mills. “That includes introducing innovative approaches that meet current needs to reduce costs. For example, by developing and harnessing technology, and drawing on the knowledge captured in our project database – soil conditions, metocean data and so on – we assist customers with project planning and sharing knowledge.”
DNV GL has introduced an internal competency assurance scheme to ensure that this experience and knowledge is shared effectively between the team, its freelance surveyors and customers. The company also continues to invest in the development of recommended practices and technical standards. “We have a Technical Standards Committee that is constantly reviewing our guidelines, procedures and standards based on feedback from customers and past projects” Mills said. “This includes, for example, technical guidance notes on leg preloading in high risk punch-through locations and jack-up recovery from those punch-throughs.”
Mills also noted that the industry and underwriters associate higher risks with prolonged tows over longer distances rather than the more challenging and demanding rig installations at difficult drilling locations; for example a highly congested field infrastructure, close proximity to live platforms and pipelines, overlapping footprints from previous rig activities and complex soil conditions. “Although in-field moves are of a shorter distance, it would be wrong to think that this means the risk level is reduced,” he explained. “Safety is the main priority and that means not cutting corners.”
“The best way to ensure high safety standards is to use top quality, trained and experienced staff, whose competency is being maintained and assured by our regulated assurance scheme”, said Mills, but he also believes in working with customers to make the provision of marine warranty surveys and rig moving services “leaner” from a cost perspective. “As an industry, we need to be flexible,” he explained. “Safety should not be compromised, but by assessing projects on a case-by-case basis and harnessing technological advances wherever possible, we can make a real difference to our customers and the industry.”