Athabasca pipeline to handle growing oilsands production

Main line welding crews, using automatic welding equipment to boost productivity, move ahead through classic Canadian winter conditions installing the Athabasca pipeline.

Sandblasting prepares the pipe for re-coating with fusion-bonded epoxy, copolymer adhesive, and a medium-density polyethylene over-jacket. [32,491 bytes]
Difficult terrain and routing were overcome by Enbridge Pipelines (Athabasca) Inc., Calgary, to build the first direct pipeline link between the oilsands deposits of northeastern Alberta and Canada's main crude-oil pipeline system.

That's according to the company, which is a wholly owned subsidiary of Enbridge Inc., formerly IPL Energy Inc., Calgary.

With affiliates, Enbridge operates the world's longest crude oil and liquids pipeline system, delivering more than 2 million bbl of liquid hydrocarbons daily through its continental network. Completion of the Athabasca Pipeline project boosts the Enbridge pipeline system in Canada and the U.S. to 11,185 miles of main pipeline.

The 30-in. OD, 340-mile (540 km) Athabasca Pipeline route extends from the Suncor Energy Inc. oilsands plant north of Fort McMurray to connecting pipelines and terminals at Hardisty in east central Alberta (Fig. 1) [39,417 bytes].

With first oil flowing Apr. 1, 1999-less than 1 year from regulatory approval from the Alberta Energy and Utilities Board (EUB)-the $475 million (Canadian) line is the largest crude-oil pipeline operating strictly within the province of Alberta, says the company.

Project challenges

Among the challenges presented to the Enbridge Athabasca design and construction team were the installation of large-diameter directional drills for several crossings and the incorporation of mechanized welding technology on the project. In addition, more than half of the pipeline traverses forest and muskeg areas accessible only in winter.

Negotiations for approval to construct 44 miles of the pipeline directly through the Cold Lake Air Weapons Range added more complexity to the regulatory-approval process, says the company.

A North Atlantic Treaty Organization air-training range lay directly in the path of the proposed line, necessitating the assistance of the Department of National Defense and the command of the Canadian Forces Base, Cold Lake, Alta., Canada's largest fighter base.

Enbridge Athabasca received regulatory approval to construct the pipeline from the EUB on Apr. 15, 1998. Within days, crews began clearing right-of-way in selected areas.

Phases

Construction was divided into two phases, coinciding with summer and winter.

The summer schedule involved construction of approximately 146 miles, beginning at the Hardisty, Alta., transportation hub and moving north to a point 23 miles south of the Cold Lake Air Weapons Range. Topography consisted primarily of cultivated land, suitable for summer construction purposes.

The more challenging winter schedule involved a 190-mile section of pipeline from the Enbridge Athabasca pump station, 16 miles north of Fort McMurray, to a point south of the Air Weapons Range.

To facilitate productive and efficient winter construction, Enbridge Athabasca required average temperatures in the range of +5° to -4° F. throughout most of winter 1998-99.

This compared with the unusually mild average temperatures of +14° to +41° F. experienced in the region only a year earlier. Fortunately for the project, says the company, traditionally cold northeastern Alberta temperatures began arriving in early December 1998.

Once frozen, the muskeg was stable enough by mid-December to support heavy equipment. This allowed work to begin through the wet terrain that comprised a significant percentage of the right-of-way on the northern winter construction spreads.

Early interest

The project took definitive shape in July 1997, when Suncor Energy Inc., one of two major commercial producers in the Athabasca oil sands north of Fort McMurray, and Enbridge unveiled a joint pipeline proposal. Expansion was already under way at Suncor which would soon open its new Steepbank Mine.

By 1997 as well, $6 billion in oilsands projects had already been announced, part of the $25 billion in oilsands investment projected over the next 30 years. Against this background, the oilsands industry was concerned about transporting its steadily increasing production.

Both Suncor and Enbridge had earlier indicated an interest with separate pipeline proposals of their own. Following commercial negotiations, the two agreed that Enbridge would construct and own the pipeline, while Suncor would commit volumes under long-term agreement.

In addition, Suncor would initially operate the line from its existing pipeline control center in Sherwood Park, east of Edmonton.

The original Suncor proposal involved a 24-in. OD pipeline to transport its own volumes. The Enbridge proposal for the Athabasca line called for 30-in. pipe. A larger pipe size was selected to ensure additional capacity, beyond the requirement of the initial shipper (Suncor), would be available to Cold Lake and Athabasca oil-sands producers.

A pumping station to be built by Enbridge on land acquired from the Suncor lease would consist of two 2,610-kw (3,500 hp) units and related facilities, including four 150,000-bbl crude-oil storage tanks.

With an initial operating capacity of 100,000 b/d and a maximum capacity of 570,000 b/d, the line was designed to meet future demand from Suncor and other potential customers.

For example, on Mar. 31, 1999, Suncor received regulatory approval for its $2-billion Project Millennium, the largest undertaking in the company's history. Designed to double current production to 220,000 b/d by 2002, the project involves mine expansion, the addition of new mining equipment, and twinning of the bitumen extraction and upgrading process.

Enbridge Athabasca says that it was crucial for proponents of the Athabasca project that the line run directly south to Hardisty rather than follow existing pipelines which lead southwest from the oilsands to Edmonton. The Athabasca route would offer Suncor the shortest route to the Hardisty hub for its shipments of semirefined oil products, diluted bitumen, and high vapor pressure (HVP) products.

The Hardisty location would provide access to the Enbridge and Express pipeline systems. Strategically, it was important for Enbridge to have a line connected not only to oilsands mining and upgrading operations of the Fort McMurray area, but also to existing and future in situ operations in the Cold Lake deposit.

Delicate negotiations

The company says that routing the pipeline around the weapons range threatened the project's economic viability.

The routing of the line was intended to enhance access for northeastern Alberta producers to major crude-oil markets in Eastern Canada and the U.S. Midwest. The ability to move large volumes was clearly an important consideration for a Western Canadian energy industry increasingly focused on the oilsands' recoverable reserves of 300 billion bbl.

On the other hand, the military's need to minimize disturbances to the Air Weapons Range was understandable. Clearing needed to be managed in order to prevent a well-defined pipeline route from becoming a handy "footprint marker" for pilots and detract from their training.

Discussions led to the Department of National Defense's approving Enbridge to cross the range, provided that the project caused minimal disruption and the pipeline remained as unobtrusive as possible. These conditions included meeting stringent requirements covering construction and reclamation.

Preconstruction work, including limited burning of brush and removal of salvageable timber from selected areas of the route, began in April 1998. Construction began around the city of Fort McMurray where a 600-m directional drill of the Athabasca River was required, and at the Hardisty end of the line.

By June, prime contractor Banister Pipelines, was overseeing a 146-mile summer spread linking Hardisty and Bonnyville. That work was completed in late September.

Directional-drill technology was used at three sites along the pipeline route, including the crossing of the Athabasca River. In addition to this crossing, separate 875-yd and 435-yd drills were also required near a main highway.

A fourth directional drill site, the crossing of the North Saskatchewan River, was attempted during summer construction. However, this drill failed. And after conferring with the appropriate regulatory bodies, Enbridge received authorization to use the traditional open-cut construction method for this major river course crossing.

Winter construction; design

Clearing for winter construction began in November 1998.

Two spreads, covering about 190 miles, were needed to complete the project from south of the weapons range to the Athabasca station and terminal adjacent the Suncor operation.

The northern section of the Athabasca Pipeline runs through the Regional Municipality of Wood Buffalo, one of the largest municipal districts in Alberta and home to many Aboriginal settlements.

The logistics of winter construction derived in part from wildlife considerations. A major caribou zone lies on the route of the Athabasca Pipeline, north of the Cold Lake Air Weapons Range. Since caribou herds migrate through the area each spring, construction had to be completed by Mar. 1.

Enbridge worked closely with lands and forestry officials to meet its deadline and ensure crews and equipment were out of the area before the animals migrated through this area.

Enbridge says above-zero temperatures in late February prompted crews to complete construction rapidly in order to be off the muskeg by early March.

Wet terrain also necessitated special approaches to design and construction.

For example, Enbridge says, it used a combination of geotechnical assessment and ground penetrating radar (a first for an Enbridge project) to delineate wet areas.

Where test digs revealed that the line would be likely to float, concrete weights or screw anchors were used to provide negative buoyancy. The minimum depth of cover for this project was 1.3 yd over top of the pipe.

In addition, the pipe required high-performance composite coating in order to withstand operating temperatures of up to 149° F. through wet ground conditions. The coating is an homogeneous, multicomponent system consisting of fusion-bonded epoxy (as the anticorrosion coating), copolymer adhesive, and a medium-density polyethylene over-jacket.

The polyethylene over-jacket provides water-permeation resistance, says the company, while the copolymer adhesive allows bonding to both the epoxy and the polyethylene top coat. Shaw Pipe Protection Ltd. developed the coating.

Mechanized welding was used through the project to facilitate greater productivity.