Dean Malhiot
Technical Director – North American, Onshore Well Operations
Abandonment of the GSC#1 Well in Athabasca, Alberta
When a long-forgotten, inaccessible leaky gas well was discovered in the Town of Athabasca, RPS applied out of the box thinking to access the well in an attempt to ensure that the well was abandoned to modern standards. Instead of building an access road down a steep riverbank or an ice road on the Athabasca River, we reached the well from above, using a crane and coiled tubing rig. Securing permits and approvals in record time, RPS plugged the well with cement, stopped the gas leak, and met the spring thaw deadline imposed by the landowner and regulators for equipment removal. The unique and pragmatic approach used by RPS to solve this complex problem reduced the project cost by 50% compared to previous estimates, was safer and better for the environment since neither the river nor the riverbank was disturbed.
A win, win, and win!
A forgotten well with a long history
The GSC#1 well was the first well drilled by the Geological Society of Canada (GSC). Drilling began in 1894 as part of an attempt to find the southeastern extent of the Athabasca Oil Sands. Though unsuccessful in its original goal, many layers of prolific natural gas were discovered to a depth of 540 metres. In January 1896, drilling stopped, the well was improperly abandoned—by today’s standards—and ultimately forgotten.
Fast forward to January 2018
In 2018, a complaint was received of a leaking natural gas well and sent out a field inspector to investigate. The old wellhead was located practically buried in the riverbank. The well was tested and found to be leaking gas at a rate of 24 m3/d, which is considered ‘non-serious’ by current standards. It was uncertain how long this well had been leaking. Still, given the environmentally sensitive location of the well, there was a high priority to have it properly abandoned. After many years of monitoring, review, analysis, and proposals, RPS developed a plan to abandon the well to current standards and stop the leak in January 2021.
Challenges to stopping the leak
The well itself
There were many questions about the well. What condition was it in? Was the casing corroded, collapsed or even present in the well? What work had been done between 1895 and 2018 but not recorded?
The GSC report from 1895 suggested that there was 4 5/8” casing left in the well, but this information had not been verified. Not to mention, of course, that safely working while gas is leaking is a concern.
The well is located within the Town of Athabasca, directly adjacent to a major highway, beside an active business and residential area. It sits on a low riverbank only 3 metres away from the Athabasca River, a designated Canadian Heritage River that flows through several communities and provincial parks downstream of the wellsite. Perhaps most challenging was the lack of vehicle access from the upper bank. The 40-degree slope made direct access to the well impossible without significant expense and environmental impact.
A tight timeframe
The leaking gas posed a very small, but potential safety risk for the Town of Athabasca. We were engaged on January 20, 2021, and planning began in earnest on January 25 with the first site visit. The fieldwork needed to be completed by the end of the fiscal year, on March 31. Due to spring thaw in Alberta, when heavy equipment on roads is prohibited, the deadline moved to March 15 to remove equipment in time.
Prior to RPS’ engagement, the option being considered to access the well was to build a 650-metre ice road on the Athabasca River during the winter and bring the heavy equipment to the site via the river. A temporary barrier, known as a cofferdam, would also need to be built to create a dry and solid area for the equipment over the well. This approach would likely double the project’s cost and delay the project by at least one year as it was already too late in the season to begin building the road.
A unique approach
Accessing the well
Instead of accessing the well from the riverbank or the river, RPS, and our partners at Codeco-Vanoco Engineering Inc., came up with a unique approach – to access the well from above.
A 275-tonne crane and a coiled tubing rig were used to reach the well overhead from the top of the river valley, eliminating the need to build a costly ice road.
Addressing the risks and securing approvals
Before beginning any work on the well, RPS needed to secure the relevant permits from municipal, provincial and national regulatory bodies.
A formal land access agreement was signed by the landowner where the crane and rig would sit. As the well sat within the flood plain of the Athabasca River, we needed to secure the required approval under the Alberta Water Act. Finally, we provided adequate assessment and notification to meet First Nations Consultation requirements.
Protecting the fish and wildlife during these types of projects is paramount. Approvals were obtained from the Department of Fisheries and Oceans (DFO), Athabasca Fish and Wildlife, and the Alberta Fisheries Department. These departments were satisfied with the mitigation measures designed by our team to protect the river and riverbank while the work was taking place.
The process of securing each of these approvals from regulators and stakeholders can routinely take several months, and equipment can’t be moved until all the approvals are granted. However, the RPS concentrated their efforts and worked closely with all regulatory bodies to ensure that the proposed operation was in compliance with all standards, resulting in a quicker than normal approval process to meet the deadline
Mobilization of equipment and crews began on February 22, 2021, and the work was completed on March 5, 2021.
A view from above
A successful project
This imaginative plan to use a crane and coiled tubing rig was a success.
Despite the challenging well location, multiple unknowns, and safety concerns, we successfully stopped the gas from leaking. Along the way, we discovered an obstruction in the wellbore near-surface and the absence of casing below approximately 65 metres. As a result of our experienced team and diligent pre-planning, we effectively overcame these challenges and permanently abandoned the well with the placement of a cement plug.
Using the crane to access the well from the top of the river valley kept project costs low, avoided a major disturbance to the riverbank, removed the need for a treacherous ice road on a flowing body of water, and allowed for on-time delivery, ten days earlier than the imposed deadline.
At the end of the project, the well was tested, and no gas was detected. The wellhead will be left in place over the next few seasons for monitoring purposes, and then it will be cut off below the surface, the casing will be capped, and the site will be reclaimed.
All stakeholders, including the Town of Athabasca, are grateful to finally have the well successfully abandoned with minimal disturbance to the river and riverbank.
Key contacts
