Estevan — After nearly a decade developing the concept of geothermal-sourced electrical power, Saskatchewan ’ s Deep Earth Energy Production (DEEP) is finally drilling its first hole south of Torquay, within sight of the American border.
A successful project will establish the first geothermal power facility in Canada.
On Nov. 8, the company, headed by CEO Kirsten Marcia, drilled its conductor pipe and rathole, in anticipation of full-blown drilling the following week. By Nov. 13 the drilling rig was moved in, and the well was spudded on Nov. 14.
That hole is going to be a significant one, aiming to be the deepest in Saskatchewan. It will surpass the two Aquistore wells by 100 metres, to a total vertical depth of approximately 3,500 metres.
Marcia spoke to Pipeline News on Nov. 9.
DEEP was formed in 2010. It ’ s had “ wonderful spurts ” she noted, where it would advance a huge distance, then be slowed down by funding needs. In recent weeks the company raised $4 million in new equity funding that allowed it to commence drilling.
The well is expected to take 25 days to drill, much longer than a typical well in that area. That ’ s in part because DEEP plans on cutting 200 metres of core at the very bottom, including cutting core into the Pre-Cambrian basement, which underlies the sedimentary beds.
“ Hopefully we ’ ll catch some core in the basement, ” Marcia said.
The company is aiming to go up to 20 metres into the basement, as that will provide the necessary depth for the logging tools that follow to scan the entire sedimentary column.
DEEP has hired John Lake, a prominent Saskatchewan geologist who once graced the cover of Pipeline News, to advise during drilling.
This hole is to be the first of six, paving the way for three production wells and two injection wells. The wells are to be placed 300 to 500 metres apart.
The initial well will be somewhat smaller in diameter, at 7 inches, right to the bottom. The subsequent production wells will be 9-5/8 inches across.
That ’ s to handle the sizeable electric submersible pumps (ESPs) that will be moving a tremendous amount of water, drawing it from the Winnipeg and Deadwood formations which make up the last 200 metres of the hole. The Icebox formation, overlaying the Winnipeg formation, acts as a caprock, as it does at the Aquistore project, approximately 29 kilometres east.
Aquistore injects carbon dioxide from the Boundary Dam Unit 3 Carbon Capture and Storage Project into a deep saline aquifer, 3,400 metres deep, and two kilometres west of the power station. SaskPower, which has already contributed $1 million to DEEP ’ s project, shared data with DEEP that it had from Aquistore.
Marcia noted that in this case, the Icebox acts as heat insulation for their purposes.
This well is a preliminary test of the resource, needed to refine assumptions, she explained.
Marcia said this well is “ about a mile ” from a similar-depth well drilled by Canadian Natural Resources in the 1980s. That well was logged with a temperature of 95 C, but three days later, it registered 126 C.
And that is why the area is so attractive, and why the company is drilling so deep. Marcia noted this is not a volcanic geothermal project, but rather one in a sedimentary basin. “ The deeper you go, the hotter it gets, ” she said, as the heat comes from the centre of the earth.
“ This is heat mining. Heat is the resource. Water is the medium to move the resource. ”
The plan is to drill this first well, and then complete it three weeks later to find its true temperature. They will flow the well for seven days, using it to model full production wells. They are also going to test the injectivity of the Mannville formation for the future injection wells.
By the end of March the testing is expected to have been fully reviewed. “ If the first well provides enough data to convince a lender for production wells, we go for it, ” Marcia said.
Then after spring breakup of 2019, the plan is to proceed with the production and injection wells, drilling them as “ doublets. ”
The injection wells, however, would not go all the way to the same depth as the production wells, but rather to the much shallower Mannville formation, which is commonly used for disposal wells in the region. There is a possibility this initial well may be used as an injection well, too. That may be needed for pressure maintenance in the reservoir.
Each production well will use an ESP that draws one megawatt, approximately 1,340 horsepower, of power. The total power produced by this project is expected to be 10 megawatts, but after the power usage from the pumps and installation facility is considered, the net power production will be five megawatts. It will be tied into a substation at Bromhead.
The long-lead portion of the project is the power production facility itself.
The above-ground installation uses the organic Rankine cycle. Using a working fluid with a low boiling point, the hot water drawn from the production wells transfers its heat via a heat exchanger, causing the working fluid to flash into a gas (i.e. boil) and drive the turbine. A cooling tower cools the working fluid back to the liquid phase for reuse. The water is then pumped down the injection wells.
This system is nearly identical in concept and in scale to what is already being done at the compressor stations on the Alliance Pipeline, which runs through Saskatchewan. Those heat-recovery power plants were installed at Kerrobert, Loreburn, Estlin and Alameda in 2008, and each produce a net five megawatts of power.
Indeed, the reality that DEEP ’ s geothermal concept is using technologies that are well-established and already in existence — drilling production and injection wells, using heat to operate an organic Rankine cycle power plant — have made it somewhat problematic in attracting funding, according to Marcia. There was nothing new, per se. But it was a new application of this technology in a sedimentary basin, and in particular, the Williston Basin, that makes it unique
The project can double in size, she noted, but at some point, it could make more sense to replicate the project as opposed to adding onto it. It ’ s scalable and repeatable.
The system will cool the water from 120 C to approximately 65 C, but that still means there is a lot of usable heat in it. While her goal is to produce electricity, not cucumbers, she feels there may be possibilities down the road to use the waste heat for greenhouses or other applications
All told, if things go well, in two-and-a-half years, Marcia said they could have power to the grid, renewable, baseload power running approximately 95 per cent of the time. She called it “ The most attractive of all renewables, ” and said that it can offset coal.
Marcia noted they are using oilfield data, technology and processes to establish a renewable resources and that without that industry, no one would even know that a geothermal resource exists here.
— Pipeline News