Technology can be transferred from the Gulf of Mexico to new markets such as the North Sea and beyond. Scott Adams, sales manager of Decommissioning Services, and Caroline Grant, Operations Manager, provide insight from Gulfstream Services Inc.
Infrastructure removal activities using cutting-edge technology in the Gulf of Mexico have been ongoing for the past 10 to 15 years, says Gulfstream Services Inc. (GSI). Fortunately, much of the technology first developed in the Gulf can be transferred to newly emerging markets such as the harsher, deeper environment of the North Sea.
With approximately 150 structures to be removed from the Gulf by yearend 2013, the current market could reach US$1 billion per year of capital spend, according to Scott Adams, sales manager of decommissioning services for Gulfstream, based at headquarters in Houma, Louisiana.
Meanwhile, some 600 offshore oil and gas installations can be found in the North Sea, according to Decom North Sea, an industry forum for the North Sea decommissioning supply chain. The structures, many of which have been producing for the past 40 years, range from modest structures in the southern North Sea to very large concrete and steel structures to the north.
“Many of these will have to be decommissioned during the next few years,” says Caroline Grant, operations manager for Gulfstream, based in Aberdeen, Scotland. In fact, under current regulatory requirements, more than 90% of the offshore structures must be completely removed from marine-state sites. The rest, such as the large and heavy steel and concrete installations, could be repurposed as a base for wind farms, wave-power structures or other uses. The workload, including an estimated 10,000km of pipelines, approximately 5,000 wells and accumulated drill cuttings, represents a cost of about $80 billion during the coming 25 years.
Yet, North Sea decommissioning operations can be challenging. “Decommissioning operations in the North Sea typically take longer than those activities in the Gulf of Mexico,” Adams says. “That’s mainly due to larger structures in deeper water in a harsher environment. Those variables require extensive planning, and typically create a shorter weather-related decommissioning seasoning. This entails the end user to further concentrate their efforts on efficiency.”
The North Sea sector technology is ever evolving accounting for weather and harsher environments. In addition, UK legislative issues have prevented foreign-based companies from proactively planning for timely decommissions. “This has caused a portion of our UK work to be reactive,” Adams says.
Grant agrees. “Until the legislation is changed, it continues to be a huge issue. Hopefully new regulatory changes, meant to take effect in 2014, will come into fruition.”
The UK’s Department of Energy and Climate Change’s (DECC) rules affect the decommissioning and recovery operations of gas fields, hydrocarbon pipelines and other types of installations.
“We are challenged by that on a daily basis, although our equipment can work in a harsh environment,” Grant says. “It is detailed to the type of vessels that can work there, such as dynamic positioning vessels, which are hired by the operators to go in and conduct work. Fortunately, our product lines are not adversely affected by the harsh environment. As a decommissioning service company, we can provide solutions as these technical requirements and feasibilities studies are completed.”
North Sea case study
A majority of Gulfstream’s work in the North Sea is pipeline- related. Recently, the company put its shear technology to work decommissioning pipelines associated with the North West Hutton platform in the North Sea. The platform was the first large fixed-steel jacket installation to be decommissioned in the region after its field production ceased in 2003.
The steel platform stood at 140m water depth on Block 211/27a of the UK Continental Shelf. A 10-in. diameter pipeline had to be left mostly on site with some sections removed, and a 20-in. pipeline had to be trenched and removed at three crossings, among other tasks in the work scope. The seabed soil was very hard with medium to large boulders in various locations.
During the decommissioning, the operator compared hydraulic shear technology cutting methods to other cold cutting methods such as dual band saws, chop saws, and abrasive water-jet cutting.
The study found that the average actual pipeline cutting time using shear technology was 11 minutes on the 10-in. line, compared to the dual-cut band saw, which took 21 minutes. The chop saw took 49 minutes, while the abrasive water-jet cutting took 1 hour and 22 minutes. Working on the 20-in. line, the shear cut in 8 minutes while the abrasive water jet cut in 1 hour and 2 minutes. The other methods were not attempted.
Operations for the cutting boat-to-boat times for the 10-in. pipeline included equipment deployment and repositioning, dredger setup, dredging, cutting, further repositioning, and hydraulic grapple recovery. The shear technology completed its tasks averaging 1 hour and 30 minutes with a total of 8 cuts. The band-saw method averaged 2 hours and 37 minutes with a total of 10 cuts. The chop saw averaged 2 hours and 59 minutes with a total of 6 cuts. The abrasive water-jet averaged 4 hours and 6 minutes while making 3 cuts.
The same operations conducted on the 20-in. line with the shear technology took 1 hour and 30 minutes with 56 cuts. The abrasive water-jet took 4 hours and 6 minutes with 4 cuts. Other methods were not used.
The operator learned that the intervention made to change the cutting technique used for the concrete coated pipelines was successful because, although the initial methods and tools that were used to make the cuts were effective, they were not time efficient, so consideration of other tools as a contingency at an early stage is important. Other learnings included that operators should ensure that their acquired survey data is recent and accurate, and that accurate soil data is necessary to allow better engineering decisions to be made. An hour in the office can save days offshore.
According to the operator’s analyses, GSI’s shearing and grappling services typically reduce pipeline decommissioning cutting times by 200% to 300%, providing huge cost savings to its customers. On three separate occasions in the North Sea GSI’s decommissioning services have been requested to replace the initially chosen cutting contractor and finish the job. Our services resulted inreduced onlocation time, equating to a huge cost savings for the client,” Adams says.
Since oil and gas shearing technology was introduced in 2005, greater than 7,000 shear cuts and 5,000 subsea debris removal grapple retrievals have been logged worldwide by GSI. This experience has provided many lessons learned along with experienced seasoned technicians.
Cause for innovation
Working and learning how to operate in the Gulf of Mexico during temporary harsh environments, or after the fact, can lead to innovative processes, services and products that can be used in both the Gulf and the North Sea. For example, after the Deepwater Horizon drilling rig explosion in the Macondo oil field on April 20, 2010, GSI was required to refocus its efforts on the decommissioning side due to more stringent government regulations. As a result, Gulfstream recently developed a new product line, known as the Spill Mitigation Device.
“This is a flow control device used in the event of a hydraulic hose or umbilical breach,” Adams says. “It minimizes the amount of hydraulic fluid, which could be released into the environment. We proactively designed, developed, and are manufacturing this patent-pending device, which will help operators meet new legislation which requires best efforts to minimize hydraulic fluid loss during an accidental hose breach or leak. Our customers are looking at it as a well-designed, proactive and effective new technology.”
While actively participating in the decommissioning market both in the Gulf of Mexico and North Sea, GSI is aware of its clients’ emergency needs.
Indeed, that capability is timely. The Gulf Coast is experiencing unusually warm weather this summer, which can heat up seawater, strengthen hurricane wind force, and enlarge a storm’s circumference. In preparedness, should a weather-related incident occur, Gulfstream has already signed first-right-of-refusal contracts for its shear technology with two major offshore operators. Adequate equipment and personnel are stationed in Louisiana and are prepared for quick response.
“Our priority is to respond to the client’s needs in the event a production platform is damaged or toppled,” Adams says. “Our current level of assets, personnel are capable of addressing any emergency decommissioning needs in the Gulf of Mexico.”
A focus on reducing personnel exposure through equipment development and eliminating chance of environmental damage is at the top of everyone’s priority list. Thus the industry is ever changing. It is moving to eliminate hot work. This means that the future of the industry will entail more cold cutting with shears, saws and abrasives, while eliminating torch cutting by divers.”
Future opportunities
In the Gulf of Mexico, great portion of the decommissioning industry’s work has been done in shallow-and intermediate-depth water on the continental shelf, Adams explains. As the industry expands and deeper water developments mature, those areas will be required to be decommissioned as well.
These deeper water activities will entail tooling powered by alternate sources such as ROV. Deeper water always demands an increase in technology even within the decommissioning sector.
Going forward, Gulfstream sees new opportunities developing in the Caspian Sea as many of the older Soviet installations have reached the end of their life cycle. “In addition to that, a market for decommissioning services in Southeast Asia, based in Kuala Lumpur, is on the rise as well,” he says.
Planning for the future with an eye toward new markets and increasingly innovative technologies is a key strategy for Gulfstream Services. To create efficiencies and streamline the processes, Gulfstream continues to invest significant capital in new technology and product-line development. OE
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