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Preparing and planning for the OCS Shell engineer describes the complex, multiyear process required to bring an oil field online in the Beaufort or Chukchi Seas Alan Bailey Petroleum News
As Shell waits behind the starting gate, champing at the bit, ready to move ahead with exploratory drilling on the Alaska outer continental shelf of the Beaufort and Chukchi seas, it may be tempting to think that the start of OCS drilling could bring a new flow of offshore oil down the trans-Alaska oil pipeline in short order.
In fact, it would be quite a few years before first oil started to flow from any Shell Arctic OCS field, Brian Miller, the engineering leader for Shell’s OCS Alaska development opportunities, told the U.S. Minerals Management Service Arctic Technologies Workshop in Anchorage on Oct. 15.
In the Arctic offshore, initial exploration, including the acquisition of seismic and the drilling of exploration wells might take three to seven years; appraisal drilling and feasibility studies for an oil discovery might take another three to seven years; selection of suitable offshore field technology and doing the preliminary design for a development project might take two to four years; and then, if things still look good, detailed engineering, construction and facility installation might take four to eight years.
“This basically totals up to … 12 to 14 years,” Miller said.
Head start However, Shell does have a little bit of a head start on its planned Alaska OCS ventures.
For example, the company’s first Beaufort Sea target, the Sivulliq prospect, is ready for the start of appraisal drilling, since two mid-1980s exploration wells previously discovered an oil pool in the prospect (Sivulliq was known as Hammerhead at the time of the original oil discovery). In the Chukchi, Shell has already acquired the seismic data that it needs and is ready to start drilling exploration wells in 2010, Miller said.
But in addition to obvious exploration and development activities such as drilling, facilities design and facilities development, there is a great deal of OCS work to be done, much of it directed at addressing concerns about the risk of damaging the environment, Miller explained.
“This is driving some data acquisition technology development and the (facility) designs that we do,” Miller said. “Our focus is really trying to reduce the environmental risk, using technology in many cases. …We also want to minimize and mitigate the impacts to the subsistence hunting lifestyle and culture.”
Shell is also hearing concerns from the North Slope villages about the impacts of an industrial economy on rural societies, with particular anxiety about the future for young people, Miller said. The company is trying hard to develop employment opportunities for people in the communities, as well as pushing for revenue sharing of federal income from OCS oil and gas production. Onshore facilities associated with offshore operations would also provide income from property taxes, while new oil developments offshore could extend the life of the trans-Alaska oil pipeline, thus prolonging the economic benefits of the North Slope oil industry, Miller said.
Environmental data Shell has been gathering environmental data, to better understand the offshore environment, ahead of any drilling operations. And the company has to conduct shallow hazards surveys and conduct site clearance operations at potential drilling sites, to ensure that drilling can be conducted safely.
But in parallel with all of that activity, the company is conducting preliminary research into future oil field development options, using environmental data to evaluate the best way to construct oil field systems, should an oil or gas find appear viable for development. Different types of oil field structure, such as the use of a gravel island or steel-legged platform, are applicable in different environmental settings. And, as well as reviewing lessons learned from the previous use of these different facility designs and performing an engineering assessment of each development option, discussions with the various stakeholders in any development project are critical to success.
“It’s really important to engage stakeholders. There’s a tremendous amount of traditional knowledge, and we also need to work with the regulators. … You need to pick the right system for the right location,” Miller said.
The leading candidate for an Alaska outer continental shelf oil field development is currently a concept involving a massive structure resting on the sea floor. Because of the severe sea-ice conditions, the structure would be fully enclosed, rather than freely standing on legs.
But at this point Shell is still working in data gathering mode: It is much too early to say what type of structure the company would actually use, Miller emphasized. And once the company has decided on its preferred development option, the company would have to submit its development plans to the appropriate government regulatory agency for the development of an environmental impact statement, a critical task that would take a number of years to complete.
“It’s a critical activity that has to happen in a location like Alaska,” Miller said.
Environmental data Meantime, some of Shell’s data gathering is targeting aspects of the Arctic offshore environment that could, if not handled appropriately, threaten structures such as subsea oil pipelines, perhaps creating the risk of a future oil spill. For example, an understanding of the gouging of the sea floor by moving sea ice is critical to the placement and burial of pipelines.
“The ice does gouge the bottom and we need to measure those gouge depths,” Miller said.
However, since some of the gouges may be hundreds or even thousands of years old, dating from times when sea conditions were different from the present day, it is also important to identify, track and date specific gouges.
Strudel scours on the seafloor, where spring melt water from rivers pours through holes in the sea ice, could also compromise pipeline safety. Areas of likely scouring can be identified from helicopter flights over sea ice near river mouths during the spring; then people return by boat to these areas in the early open water season, to locate scours before new sediment can fill them, Miller said.
Shell is also researching coastal stability in areas where a future oil pipeline may come onshore. The company is using data from surveying and satellite photography to try to find locations where a pipeline transition to land could be achieved without the need to build a protective structure. A site would need to remain viable for the entire life of an offshore oil field.
“You have to predict what’s going to be happening 30, 40, 50 years into the future,” Miller said.
Geotechnical surveys In addition, Shell has been conducting geotechnical surveys along a potential pipeline route in the Beaufort Sea, determining what type of soil is present and measuring the soil strength. This type of information is important in ensuring a safe oil platform design, as well as in making sure that a pipeline can be adequately buried and protected.
Other data collection activities that have been in progress include the measurement of sea-ice movement using satellite buoys on the ice, and the evaluation of ice structures using computer-processed stereoscopic aerial photos. The assessment of ice structures will enable a determination of whether a vehicle such as a hovercraft could safely make its way on the ice to and from an offshore operation, as well as providing some of the information needed to understand the potential impact of ice on an offshore structure, Miller said.
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