Operator to replace Kuparuk pipeline

ConocoPhillips says work also will enable line to accept smart pigs for corrosion monitoring; project expected to take two years

Eric Lidji

Petroleum News

ConocoPhillips plans to replace more than four miles of pipe in the Kuparuk River unit early next year to allow for better corrosion monitoring.

The replacement will allow unit operator ConocoPhillips to run smart pigs and maintenance pigs through the Kuparuk Pipeline Extension. Pigs are mechanical devices fed through a pipeline for different purposes. Smart pigs measure damage along the walls of a pipeline, while maintenance pigs clean out deposits that could lead to corrosion.

The shortest of the major pipelines on the North Slope, the Kuparuk Pipeline Extension runs about nine miles from Central Processing Facility-2 to Central Processing Facility-1, both in the eastern half of the Kuparuk River unit.

Originally, the westernmost piece of North Slope transportation infrastructure when it came online in 1981, the extension now connects the Alpine Oil Pipeline and fields to the west with the Kuparuk Oil Pipeline, which feeds into the trans-Alaska oil pipeline.

During its first 25 years in operation, the Kuparuk Pipeline Extension moved more than 73 million barrels of sale-quality oil into the gathering facilities at Prudhoe Bay. And although the small pipeline has been a workhorse, that much oil naturally takes its toll.

But monitoring the Kuparuk Pipeline Extension is cumbersome.

Currently, ConocoPhillips can’t pig the above-ground pipeline because of its odd design: About half of the line is 12 inches in diameter, while the rest is 18 inches in diameter. As a result, the field operator can only monitor the line externally, using ultrasound equipment.

The upgrades will enlarge the narrower section, making the entire pipeline 18 inches in diameter. It also will use existing vertical support members and pipeline racks. The old pipe will be cleaned and recycled.

Along with the replacement effort, ConocoPhillips plans to build pig launching and receiving terminals at either end of the pipeline. The terminals will be built in basins used for collecting snow during winter cleanups and melt-water during spring breakup.

The company said it expects to finish the entire project by the fall of 2010.

Corrosion a focus since 2006

Corrosion became a public issue in March 2006, after sediment build-up in pipelines at the BP-operated Prudhoe Bay field caused the largest oil spill in North Slope history.

Following the spill, ConocoPhillips voluntarily evaluated its pipelines at Kuparuk under a program devised by the U.S. Department of Transportation. The federal agency came to Alaska in November 2006 to inspect ConocoPhillips’ North Slope pipelines.

But the program requires ConocoPhillips to conduct further inspections. The smart pigs will allow the company to inspect the pipeline to DOT standards by the agency’s deadline in May 2011.