By Patrick O’Donoghue, Trenchless Crossing Manager, Michels Canada
The Direct Pipe method was used for the first time in Canada when Michels Canada Co. completed the Beaver River crossing in northeast Alberta.
The 42-inch oil pipeline spanned 1,122 feet under the Beaver River about 12.4 miles northeast of Bonnyville, Alberta. Michels is one of a select group of contractors able to perform Direct Pipe installations, which complements its established HDD and pipeline work in the U.S. and Canada.
The Direct Pipe method was first used in 2007 to cross the Rhine River in Germany. Unlike horizontal directional drilling (HDD), Direct Pipe is a single-pipe installation that combines microtunneling and a thrusting system to directly install the product pipe. It is an efficient method for use on projects where geotechnical challenges wouldn’t be a good fit for HDD such as unconsolidated sand, gravel and cobbles.
Michels and project partners Inter Pipeline Ltd. and Complete Crossings Solutions had started preliminary design and planning almost a year before beginning work on the project in August 2013. Site setup was completed in approximately two weeks and Michels broke through to exit on Labor Day weekend.
Michels used the Direct Pipe system that combined a Herrenknecht Pipe Thruster with a Herrenknect microtunnelling machine. The system is operated from the surface with an operator who monitors and corrects alignment changes and controls the tunneling head and thrusting unit simultaneously. The cutting head and product pipe are kept within the predetermined design parameters. The microtunneling head removes material from the cutting face and returns it to a cleaning plant that separates mined material from the drilling mud and recycles it back down to the cutting head.
A gripper thrust system clamps onto the pre-tested 42-inch product pipe and pushes it into the borehole. The thrusting system is designed to maintain the integrity of the pipe and pipe coating while thrusting.
While Direct Pipe is relatively new to North America, Michels Direct Pipe service is able to provide clients another viable tool for trenchless crossing from 36 to 48 inches.