Fairbanks, Alaska, and western Canada locations were evaluated in the study. Several scenarios were evaluated for each location and the company said most of the scenarios were economically viable.

"The results confirmed our initial evaluation that a petrochemical complex, including gas processing and a plastics plant could potentially enhance the economic viability of an Arctic gas pipeline," said Phil Wright, president of Williams' energy services unit.

"Many significant assumptions will have to be realized for this conclusion to hold true but we will continue to evaluate market conditions," Wright said.

He said it would be at least three years before any money would need to be spent on infrastructure.

"In the meantime," Wright said, "we must continue to work to evaluate market conditions, as well as mitigate the risks associated with this critical group of projects."

Williams said a petrochemical project is contingent on commercialization of Alaska North Slope gas.

Chemical Market Associates Inc. was one of the primary outside research firms assisting in the study.

"While locations in Alaska and western Canada appear to be potentially feasible, they each have different markets," said Rich Cornelius, vice president of Chemical Market Associates.

"A petrochemical facility in Fairbanks would ultimately export most of the products to Asia, while a facility in western Canada would ship most products to the north and Midwest United States," he said.