Low Flow Impact Study

Alyeska has completed a comprehensive Low Flow Impact Study (LoFIS) on behalf of the TAPS owners. The study evaluated the potential risks associated with declining throughput and lower oil temperatures and identified mitigation measures.

“The Low Flow Impact Study is a critical step toward addressing the many challenges associated with declining throughput,” said Tom Barrett. “I want to thank Pat McDevitt and the study team for a job well done.”

“The study findings make it clear that the technical challenges compound and increase in complexity as throughput declines. The simplest, most direct and cost effective path to dealing with these challenges is to stop the decline by adding more oil.”

The LoFIS identified potential challenges with throughput levels between 600,000 and 300,000 barrels per day (BPD). Potential challenges include:

• Water, present in oil as small droplets, is expected to separate out in a layer at the bottom of the pipe at 500,000 BPD and lower. Separated water will increase the potential for ice formation and corrosion.
   
• Wax build up in the pipeline is present at current throughput levels and will continue to increase as throughput declines.
   
• As throughput drops below 550,000 BPD, oil temperature will have the potential to drop below the freezing point of water and form ice in the pipeline during the winter months. Ice could damage pumps and equipment.
   
• Crude oil temperatures at 350,000 BPD could allow soils surrounding buried sections of the pipeline to freeze, which would create the potential for ice lenses. Ice lenses could cause movement and damage the pipeline via frost heaves.

Mitigation measures recommended in the study include:

• Minimize the impact of temperature decline by adding heat and insulation.
   
• Modify the water and temperature specifications for crude oil entering TAPS.
   
• Adjust the pipeline pigging program as throughput declines

To see the study, click on the following links:

Executive Summary

Full Study
 

Previous published documents related to the study:

Low flow fact sheet

2011 low flow slides.

Executive Summary - June 2009

Q&A Set #2 - 12/9/08

Q&A Set #1 - 10/2/08
 

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