Providing coverage of Alaska and northern Canada's oil and gas industry
August 2018

Vol. 23, No.34 Week of August 26, 2018

More details emerge

BLM publishes more detail on ConocoPhillips’ planned Willow development

Alan Bailey

Petroleum News

In conjunction with the scoping process for an environmental impact statement for ConocoPhillips’ proposed Willow oil field development in the northeastern National Petroleum Reserve-Alaska, the federal Bureau of Land Management has published more details from ConocoPhillips’ plan for the field. In May the company filed what it referred to as a master plan for the development, in anticipation of BLM having to produce an environmental impact statement for the project. The master plan published was somewhat of an outline in nature. The document that BLM has now published puts a bit more flesh on that plan.

However, ConocoPhillips has not yet made a final investment decision for the project, with that decision presumably requiring more detailed engineering and technical analysis, to pin down the project economics.

Meanwhile BLM is seeking public comments on the scope of the EIS.

Processing facility and drill sites

In general terms, the development, in the Bear Tooth unit, will entail the construction of a central processing facility, five initial drill sites, and an infrastructure pad for support facilities including personnel accommodation, ConocoPhillips’ plan says. The new BLM publication indicates that the central processing facility will be co-located with the Bear Tooth No. 3 drill site. Gravel roads will provide access to the field facilities from the Greater Mooses Tooth unit to the east and to the drill sites from the central processing facility.

Road layouts may involve bridge crossings of the Judy Creek, the Fish Creek and the Kalikpik River. The layouts are designed to minimize road lengths, to the extent possible to place roads on higher and drier ground, and to minimize wildlife disturbance, the publication says.

A 5,400-foot airstrip would be constructed near the infrastructure pad, for access by fixed-wing aircraft.

Sealift of modules

The development plan envisages the delivery of modules for facility construction by sealift via a 12-acre gravel module transport island in Harrison Bay, in the nearshore waters of the Beaufort Sea, and via an onshore ice road to the project site. The gravel island would be constructed during the 2021-22 winter season using an adjacent ice pad.

Modules would be barged to the transport island in the summer of 2023 and staged on the island until the winter construction season, when the modules would be moved by ice road to the project site. However, modules for drill sites BT4 and BT5 would be delivered by a second sealift in the summer of 2028, for installation during the following winter.

At the end of the island’s design life all gravel slope armoring and other manmade items would be removed, so that the island would be reshaped naturally by wave and ice action, the publications says.

Pipeline system

Once the field is in operation, infield pipelines will carry produced fluids from the drill sites to the central processing facility. An export pipeline will then transport sales-quality crude oil from the central facility to a tie-in point on the existing Alpine pipeline at the Colville River Delta 4 North pad. The development would also require the construction of a seawater pipeline, a diesel pipeline, and a freshwater pipeline. Pipelines would run parallel to roads; valves would be installed on each side of pipeline creek and river crossings.

The layout would be designed to minimize redundant parallel pipelines. For example infield lines from four of the drill sites would be connected in series, through a single connector to the processing facility, with just the fifth site needing its own pipeline system.

The seawater pipeline would carry seawater, presumably for water injection, from the Kuparuk River unit to Willow. Similarly a diesel pipeline would carry refined hydrocarbon products from Kuparuk. These two pipelines would be installed under the Colville River using horizontal directional drilling. The lines would be bundled together inside an outer pipeline casing, for the protection of the permafrost from heat and to contain fluids in the event of a pipeline leak.

Produced water separated in the central processing facility would be re-injected into the subsurface for reservoir pressure maintenance and for waterflood for improved oil production. Produced natural gas would be used as fuel in field facilities and would be injected back into the reservoir rocks for reservoir pressure maintenance and improved oil recovery. Gas may also be used for gas lift, to improve well productivity.

50-well drill sites

Each drill site is being sized to accommodate at least 50 wells with a 20-foot wellhead spacing. Wells could be either production wells, or injectors for injecting water or gas into the subsurface. The infrastructure pad, the operational base for the field, would be located about a mile from the central processing facility, away from any potential blast hazard associated with the processing system. In addition to a personnel camp, the infrastructure pad would house a variety of facilities, including a warehouse, communications infrastructure, a helipad and an emergency response center. Two water source access pads would provide access to freshwater intakes from two adjacent lakes.

Announced in 2017

ConocoPhillips first announced its Willow discovery in January 2017, following the drilling of the Tinmiaq No. 2 and Tinmiaq No. 6 wells, although it appears that the company actually found the Willow oil pool in 2002 through the drilling of the Hunter A well. In the past winter the company further appraised the find through the drilling of the Tinmiaq Nos. 7, 8 and 9 wells. The field reservoir is in the Nanushuk formation, at a depth of a little over 4,000 feet in a similar geologic setting to the major oil field in the Pikka/Horseshoe trend that Oil Search and its partners are developing on the east side of the Colville River.

In July ConocoPhillips upped its estimate for recoverable resources in Willow from 300 million to 400-750 million barrels of oil equivalent. The company had previously indicated that production from standalone facilities could peak at as much as 100,000 barrels per day. The company has indicated that development of Willow will likely cost $2 billion to $3 billion over four to five years after a final investment decision is made, with first oil flowing from the field by 2024 to 2025. A further $2 billion to $3 billion would then be spent on cumulative drilling over multiple years to sustain production.

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