Climbing a river slope for safer pipelines in northeastern Alberta

In January 2022, Brownline Canada steered two parallel pilot bores near Fort McMurray, Alberta. The two steel pipes are part of a pipeline network constructed to transport crude oil. This oil is extracted from the Athabasca tar sands in northeastern Alberta and transported south to refineries, export pipelines, and other delivery locations in the Edmonton area.

The first crossing was 1185 m / 3888 ft long and designed to replace an above-ground pipeline that connected two pump stations along the Horizon Pipeline system. The exposed pipeline was located on a steep slope that was prone to landslides which necessitated a safer alternative. The second crossing, measuring 1110 m / 3642 long, was for a pipeline that is part of the Syncrude Pipeline system. Construction of these two pipelines using the HDD method at this location promised safer operations of these pipelines but presented unique construction challenges.

Among these challenges was the elevation difference of 160 m / 525 ft between entry and exit and the designed depth of the drill path from surface. At its deepest point, the drill path was 132 m / 433 ft deep. The intersection zone for both crossings was at the exit tangent near the top of the slope. These crossings were in near proximity to an environmentally sensitive area adjacent to the Athabasca River and demanded careful annulus pressure monitoring while drilling.

To overcome these challenges, our client required the use of the highly accurate Drillguide Gyro Steering Tool (GST) along with the technical knowledge of the Brownline team to successfully complete these crossings. With casing installed from both ends, the GST was able to accurately log the position of the casings and begin drilling from both sides to the planned intersection zone. The ground formation, which included a mix of clay, clay shale, oilsands, and limestone, also presented some challenges that required interchanging both a jetting assembly and mud motor. The GST’s continuous real-time annular pressure measurements while drilling informed our client to take suitable measures to prevent any inadvertent returns. Both parallel drillings utilized Brownline’s Radar add-on, allowing the assemblies on both ends to communicate with each other and determine their relative positions once the drill heads neared each other. With the help of the Radar systems, the Brownline team was able to come up with a meticulous plan to precisely execute a successful merging of the two bores.

Brownline’s highly accurate tools and deep technical expertise were able to deliver the desired outcome to the satisfaction of our client in a safe and efficient manner. The pilot bores were completed without any effects or disturbances to the surface above ground. These pipeline systems will now operate more safely without a toll on the environment or risks to the integrity of the pipeline.

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