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The story of BP’s Liberty development
A browse through the U.S. Minerals Management Service archives shows that Shell originally drilled two wells in 1982 and one well in 1987 in the area of BP’s Liberty field, testing a prospect that Shell called “Tern” and finding evidence of producible hydrocarbons in the 1987 well. The company subsequently dropped the leases.
BP picked up the leases in a 1996 MMS Beaufort Sea sale and in 1997 discovered the 100 million barrel Liberty field when drilling an exploration well from the Tern gravel island. The company found that the Liberty oil reservoir is closely analogous in geology and production characteristics to that of the nearby BP-operated Endicott field.
In the late 1990s BP started moving forward with plans to develop Liberty, with MMS preparing an environmental impact statement for the project. The initial field design involved an offshore gravel island over the field, with an oil pipeline to shore, in a similar concept to the BP-operated Northstar field, in the Beaufort Sea northwest of Prudhoe Bay.
Morphed to extended reach By 2006 the original development concept had morphed into the current field design, involving the drilling of ultra-extended reach wells from the Endicott satellite island. BP said that, with the Liberty wellheads located at Endicott, the Liberty field could share production facilities with the Endicott field, as well as sharing the Endicott oil export pipeline — production from the aging Endicott field was by then far below its early peak.
“In developing Liberty in this way we eliminated the need for new offshore islands; … we eliminated the need to put new processing facilities in place; and we eliminated the need for new buried pipelines to bring processed crude back to shore,” Darryl Luoma, BP’s general manager for the Liberty project, told the Alaska Support Industry Alliance in April 2009.
In December 2007 MMS released its environmental assessment of the Liberty project, essentially saying that because Liberty would use an existing industrial complex the project would have no significant adverse environmental impacts.
Using data from Shell’s original Tern wells, from the Liberty discovery well and from 3-D seismic data, and using its knowledge of the production characteristics of the Endicott field, BP has prepared a production plan for Liberty. That plan involves the drilling of up to four production wells and up to two injection wells, with the injection wells used to flood water through the field reservoir to help push oil out through the production wells, a technique commonly used in the relatively low-pressure oil fields of Alaska’s North Slope.
—Alan Bailey
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