Colville River Pipeline Crossing

Alaska

Michael Baker has supported the development of the Alpine Oil Field, owned and operated by ConocoPhillips, since 1995. Part of the development included a sales oil pipeline to connect Alpine with the existing North Slope infrastructure. The biggest challenge was getting across the Colville River, which drains more than 20,000-square-miles into the Arctic Ocean. After reviewing three crossing mode alternatives, a horizontal directionally drilled (HDD) approach was selected because it required the shortest construction duration and created the smallest construction footprint.

The Colville River Crossing was the first horizontal directional drilled (HDD) pipeline under a permafrost-bound river. We designed and managed the construction of the 4,300-foot arctic HDD river crossing. The project consisted of four HDD penetrations: 14-inch crude oil in 20-inch steel casing; 12-inch seawater in 18-inch casing; 8-inch utility bundle; and 8-inch impressed current anode for cathodic protection. This was the first time a cased-steel pipeline has been installed in an arctic HDD river crossing. It was designed to protect the river in the event of pipe failure. This also was the first time a fiber optic sensor in the steel casing had been used for leak detection.

Development on Alaska’s North Slope must balance the needs of environmental, regulatory, cultural and industry stakeholders. This project successfully balanced those interests. The river crossing simultaneously achieved the goals of minimal impacts on the nearby Inupiat people and river environment and successful horizontal directional drilling of an arctic river.