USGS set to upgrade arctic oil, gas reserves

The new appraisal will include several provinces not previously covered. The USGS already has issued assessments for three provinces in this category. For the Laptev Sea off Russia’s northern coast it estimates reserves of 9 Bboe, comprising 40% oil and 60% gas. For Canada’s Mackenzie Delta, the figure is 29 Bboe, equally divided between oil and gas. Recently, the agency also issued an estimate of 7.3 Bbbl and 52 tcf for reserves in the west Greenland-east Canada province.

The revised estimates for provinces covered in the 2000 survey, when added to new estimates for provinces not included in the first program, suggest that the USGS has identified an additional 53 Bboe since 2000, according to Sawhill. The degree of uncertainty in the figures has also been reduced, he adds.

While many of the areas covered in 2000 were largely unexplored and geological data limited, the flow of information has since begun to increase exponentially, in part due to the UN’s Law of the Sea process. The new assessments are, therefore, based on better knowledge.

Despite limited exploration to date in the arctic, the region already accounts for 15%, or 400 Bboe, of discovered hydrocarbon reserves, comprising 130 Bbbl of oil and 1,500 tcf of gas. Most of these reserves are in Russian territory or waters, including three-quarters of the oil and 90% of the gas.

Understanding ice forces

Among numerous topics covered at the Oslo conference was the contention that offshore developments in arctic regions will almost certainly require surface-piercing installations which will encounter floating ice. A good understanding of ice forces is necessary for the design of such installations, said Andrew Palmer, Keppel Professor at the Center for Offshore Research and Engineering, Department of Civil Engineering, National University of Singapore.

Early studies, he pointed out, idealized ice as elastic/plastic. That approach implied that there was no size effect, so model tests could be readily scaled up to determine the actual forces on full-scale structures. In practice, however, such a model is inadequate. Measurements of the crushing force that occurs when large ice floes collide with Hans Island in the Kennedy Channel between Greenland and Canada have shown that there is a strong size effect.

There is a broad consensus today that the size effect is real. Most design equations in codes incorporate a size effect, and vertical-sided structures can be designed with a reasonable level of confidence. The explanation of the size effect, however, remains controversial, involving a combination of fracture mechanics, non-simultaneous failure, high-pressure zones (since small-scale tests show that the contact force between ice and a structure is very far from uniformly distributed), and fracture toughness.

Understanding fracture mechanics – what happens as ice collides with a structure and fractures – has proved particularly problematic. Whereas most fracture mechanics deals with the growth and propagation of a single crack, or small groups of cracks, continuous ice crushing against a structure is completely different, resulting in tens of thousands of cracks of different lengths propagating in different directions.

No satisfactory conceptual model for predicting the effect of ice forces on offshore structures has yet been developed. The behavior of very slow-moving ice, as in glaciers and icecaps, is comparatively well understood, but of little relevance for offshore structures, which are more likely to be interacting with faster-moving ice.

Most experimental work and empirical observations apply to structures with vertical sides. Sloped sides may offer advantages for arctic installations as they are thought to reduce ice forces, though there is a lack of evidence from field tests. However, trials in Bohai Bay indicated that the addition of small cones to the legs of conventional jackets reduces both ice forces and self-excited vibrations.

A draft code for the design of arctic offshore structures, ISO 19906, was released for review in 2007. The review process is not yet complete, and many uncertainties remain. “We must see the 2007 draft as an interim step,” Palmer says. “There is much to do.”

Shell in R&D drive

Shell, which is committed to oil and gas operations in the arctic, also is involved in a wide range of research and development activities to ensure it does not harm the environment.

The company first established operations in Alaska more than 50 years ago. In the past, Shell’s arctic activities have been mainly onshore or near-shore, but having acquired extensive acreage in the last three years in both the Beaufort Sea and the Chukchi off northeast Russia, its focus has switched firmly offshore.

The company commissioned seismic acquisition here in 2006 and 2007, and plans to continue this program in both seas this year. These operations are conducted to avoid impacting local subsistence activities – no activities, for example, take place during the whale-hunting season. Shell also operates an extensive marine mammal monitoring program for its exploration campaign. (Editor’s note: See separate article about this project in the September issue ofOffshore.)

Shell Technology Norway performs part of the company’s arctic-related R&D, says senior environmental adviser Gina Ytteborg. This includes monitoring recommendations issued by the Arctic Council’s Arctic Monitoring and Assessment Program. The latter’s 2007 oil and gas assessment study concluded that oil spills are the greatest threat in marine environments, and that planning and monitoring can and will help reduce risks.

Shell is also a sponsor of the Oil in Ice joint industry project (JIP) managed by the Sintef research institute in Norway. The presence of ice adds an extra dimension to oil spill response, says Ytteborg. In some ways it makes the task easier – ice contains and preserves oil, and can therefore provide a larger window of opportunity for dealing with a spill.

In 2006, the JIP tested three systems for detecting oil under ice, and now is engaged in improving spill response. The presence of ice makes the use of booms and skimmers challenging, but successful tests have been carried out to burn oil, with 96% being burnt off in a matter of minutes in one test under controlled conditions. One well-proven ignition method is performed from a helicopter.

Dispersants offer an alternative approach to handling oil spills, and also can be applied from the air. In many places around the world dispersants are a proven method, and studies have been initiated to adapt the application to arctic areas, Ytteborg says.

Shell also is involved in a project led by the Norwegian Oil Industry Association, OLF, to monitor subsea leaks. The first phase investigated techniques for monitoring areas close to seabed templates, where the risk of leakage is highest. A best practice document has been suggested as a follow-up.

Barents Sea HSE standards

Norway and Russia are working to harmonize health, safety, and environment (HSE) standards for operations in the Barents Sea, which the two countries share. The Barents 2020 project is sponsored by the Norwegian foreign affairs ministry and managed by DNV.

The project is timely not just because both countries are intensifying their exploration and production activities in the Barents, but also because Russia is in the process of updating its HSE standards to conform where possible to international guidelines, said DNV’s project manager, Erling Sæbø. Russia has an unequalled experience of operations in arctic waters, notably in shipping, while Norway is known for its well- developed HSE regulations.

It was a challenge to get discussions going, Sæbø says, but after a year of working together, a good dialogue has been established. Existing regulations provide a good starting point – in Norway’s case, probably 85% of standards developed for the North Sea can also be applied to the Barents Sea.

But since these standards do not explicitly address arctic challenges, they are inadequate in some ways. Regulations for ice-class shipping, for example, have mainly been adapted for operations in the Baltic Sea, but conditions in the Barents and Kara seas are significantly more difficult.

Similarly, offshore installations such as drilling rigs or production platforms face significantly harsher conditions in arctic seas, and will have to be enclosed to enable staff to work in extremely low temperatures. This not only changes the classification of the platform, but has a knock-on effect. For example, explosion risk is increased in an enclosed environment. The relatively low level of activity in arctic areas to date also means international regulations have not had the benefit of feedback from actual applications.

Risk is another focus area for the two countries. In many ways, the consequence of an incident is likely to be greater in the arctic due to factors such as the distances involved, the hours of darkness in the winter months, and the lack of infrastructure.

Having established good working relationships, the next step for the project will be to identify particular areas of concern and to establish joint working groups to tackle them. There is a lack of real knowledge, says Sæbø, in what is needed to deal with oil spills in ice, and the effects of ice loadings on structures.

The two-year project is due to produce its final report in late 2009. When standards have been agreed, they will be sent to the relevant bodies such as the International Labor Organization and the two countries’ HSE bodies.