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New plumbing at Prudhoe to boost oil production by 176 million barrels BP's gas cap pressure-maintenance project, planned for third quarter 2002 startup, includes repairs and enhancements at seawater treatment plant, new seawater pipeline to East Dock and injection wells Kristen Nelson PNA Editor-in-Chief
Where do you get 176 million barrels of additional North Slope crude oil? You can look for a new field such as Northstar, expected to produce 176 million barrels, or you can find a way to produce that many additional barrels out of an existing field such as Prudhoe Bay, which has already produced more than 10 billion barrels of oil and is expected to produce at least another 3 billion barrels.
Prudhoe Bay (and Northstar) operator BP Exploration (Alaska) Inc. is doing both: in addition to Northstar, expected to come online later this year, BP has applied to the state for a gas cap water injection project which will recover 176 million incremental barrels of oil from Prudhoe Bay.
Water will be injected into the gas cap area of the field. The project will require repairs and upgrades at the seawater treatment plant and the eastern seawater injection plant, construction of a new 32-inch diameter seawater pipeline from flow station 2 to east dock and surface injection facilities at east dock.
“The pressure support provided by the water injection is expected to arrest the pressure decline and recover 176 million barrels of incremental hydrocarbon liquids,” BP told the state in a Sept. 25 application.
Up to 650,000 barrels per day of seawater will be injected into the Prudhoe Bay gas cap from an injection site at the East Dock staging pad.
Injection would begin in the third quarter of 2002 with an initial injection rate of 480,000 barrels per day, ramping up to 650,000 barrels per day. The project is estimated to run for 20 years, with a total of more than 4.2 billion barrels of seawater injected. Three components to development BP said the plan requires repairs to the existing seawater treatment plant and eastern seawater injection plant, a new seawater pipeline from flow station 2 to the East Dock staging pad and surface injection facilities at the East Dock staging pad.
The seawater treatment plant at the northern end of the West Dock causeway carries out initial processing of seawater for injection. Seawater is strained, heated, filtered and de-oxygenated and chemicals are added to control bacterial growth and prevent corrosion and foaming.
The heated water is then pumped to the eastern seawater injection plant. Additional heat may be added and the water is pressured to final injection pressure and sent to injection wells through field pipelines.
BP said that implementing gas cap water injection requires seawater throughput to be raised to 900,000 bpd to allow 650,000 bpd to be transported to the East Dock staging pad for injection, while continuing to provide approximately 200,000 bpd at drill site 11 and drill site 4. Repairs required at existing plants The seawater treatment plant was designed for 2.2 million bpd and in the past has processed as much as 1.4 million bpd of seawater. BP said that as seawater demand has declined, the facility throughput declined, and repairs are required to get the seawater treatment plant back to the 950,000 bpd rate.
Repairs needed include pump repairs and replacement; piping replacement and upgrades; filter control upgrades; and plant control system upgrades.
Fewer repairs are needed at the eastern seawater injection plant. There, BP said it will need to redesign and replace waste heat louvers and add new pump isolation valves.
The schedule is to begin construction in November and December, complete construction in the spring, hydrotest the pipeline in the summer and compete the project next September.
BP said the Alaska Department of Environmental Conservation has said that no additional air permits are required under federal guidelines. Both plants were previously permitted at 2.2 million bpd.
The seawater pipeline will run between flow station 2 and the East Dock staging pad.
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