Shell exploration drilling advances at Burger J
Shell is keeping a tight lid on information about its Chukchi Sea drilling for now.
The semi-submersible Polar Explorer is at work drilling the first well in Shell’s 2015 program, Burger J, and a weekly report issued Aug. 25 by the U.S. Bureau of Safety and Environmental Enforcement, or BSEE, indicated that a shallow casing string has been installed and cemented into place on the well.
This is an initial “string” of casing that is typically installed once the “mud-line cellar” excavation is completed, a step Shell reported earlier. “Casing” refers to heavy steel pipe installed in the well through which the actual drilling tools are operated and drilling “mud,” or fluid, is circulated to keep up pressures at the bottom and to remove rock cuttings from drilling.
The casing is cemented into the formation to add strength to the well, which increases safety.
As the Polar Pioneer works, a second drill vessel, the Noble Discoverer, is moored nearby at a second well location, Burger V. Federal rules require two drill ships to be in the vicinity in case a problem occurs on a well and assistance to the rig drilling the well is required.
Rules also prohibit the second rig, in this case the Noble Discoverer, from drilling while the first rig, the Polar Pioneer is operating. Rigs operating simultaneously in the Chuchi Sea must be at least 15 miles apart, to minimize noise effects on marine mammals and other wildlife, under U.S. Fish and Wildlife Service regulations.
Shell has applied for permission to drill up to five exploration wells in its initial Beaufort Sea program but only two wells, Burger J and Burger V, would be drilled this year, under the approvals that have been given.
Shell drilled a partly-complete exploration well in 2012, Burger A, but chose not to return to that specific location this year.
The Burger prospect is a more-or-less confirmed discovery about 60 miles off the northwest Alaska coast. Shell drilled the first wells there in 1990 and 1991 and made the initial discovery, but at the time it was believed to me mainly gas and, although seemingly large, uneconomic in such a remote location and with no gas pipeline likely.
Shell returned in recent years, did a reevaluation with modern seismic and other exploration tools, and bid to reacquire the leases at Burger in the federal outer continental lease sale held in 2008.
It is still not known if there is also significant oil at Burger in addition to gas, and if so whether there is enough to justify the huge costs of constructing offshore production facilities, 60 miles of pipelines to shore and more pipeline across the National Petroleum Reserve-Alaska to the Trans-Alaska Pipeline System.
However, Shell and federal officials have high hopes that significant quantities of oil and gas can eventually be found and developed in the Chukchi Sea.
ConocoPhillips, Statoil and Repsol also acquired acreage but Shell has taken the lead in exploration.