A demonstration project to study the injection of carbon dioxide (CO2) captured from SaskPower's Boundary Dam coal-fired power plants into a deep saline formation holds significant promise.

The Aquistore Project has been receiving a portion of the CO2 captured from SaskPower's Integrated Carbon Capture and Storage(CCS) Demonstration Project at Boundary Dam via a pipeline to an injection site on SaskPower's property about two kilometres west of the power station. As of the end of April 2016 over 50,000 tonnes of CO2 have been injected.

This CO2 is being injected into a 3.4-kilometre-deep well—the deepest ever drilled in Saskatchewan. The CO2 is compressed to become dense and liquid-like, and remains in the state because of the pressure and temperature of the reservoir. The injected CO2 is now being evaluated and monitored for the duration of the project using millions of dollars in measuring equipment at the site.

Aquistore is a collaborative project between governments and industry and has received $9 million in funding from Natural Resources Canada, $5 million from Sustainable Development Technology Canada, and another $5 million from the Government of Saskatchewan. A significant component of the $45 million overall project funding is coming from the energy and petroleum sectors, including Enbridge, Schlumberger, the Korean National Oil Corporation, Co-operative Consumer Refinery Limited, and SaskPower. Other partners have contributed through direct funding and in-kind contributions including fieldwork, research and equipment. SaskPower is the owner and operator of the wells and the pipeline.

The Petroleum Technology Research Centre (PTRC) located at Regina's research park manages the research and monitoring components of the project. The Science and Engineering Research Committee (SERC)—a body of expert scientists and researchers specializing in CO2 storage from academic and research organizations across Canada and the U.S.—acts as an advisory committee and will continue to provide expert opinion and technical oversight of the project, including the measurement, monitoring and verification.

"Simply put, this project is intended to demonstrate that storing captured carbon dioxide 3.4 kilometres underground is a safe, workable and long-term solution to help reduce greenhouse gases," says Kyle Worth, Aquistore Project Manager at PTRC.

A great deal of research has gone into the project so far. "The design phase began in 2009, we started breaking ground in 2011. We have been injecting since April of 2015," says Worth.

The incentive for Aquistore is huge. "The majority of climate scientists agree if we do not reduce CO2 emissions, significant climate change will occur, including extreme weather and temperature events that could affect us both locally and globally. So for PTRC, carbon capture and storage is a key part of the solution to reducing CO2 emissions from large industrial sources," explains Worth. "The second driver is SaskPower's need to meet federal emission regulations; without implementing CCS, SaskPower would have to close its existing coal-fired power plants and invest heavily in alternative energy sources."

Despite a low population, Saskatchewan has Canada's highest per-capita greenhouse gas emissions. Coal-fired power plants are the largest fixed emitters of greenhouse gases. Saskatchewan is one of three provinces where the carbon footprint of electricity generated by coal plants is so high, driving a gas-powered car is still greener than driving an electric vehicle. The good news is, however, that Aquistore alone—with a daily capacity of 2,000 tonnes of CO2—is capable of storing emissions equivalent to 250,000 vehicles per year.

"The biggest benefit of Aquistore is that it will allow Saskatchewan to continue to use readily-available coal as an economic energy source," says Worth, "but there are secondary benefits as well that may ultimately help build regional, national and global capacity for carbon capture and storage, and that can be shared with industry. The data from projects such as Aquistore is relevant to not just CCS organizations, but to the oil and gas industries, geologists, or other fixed emitters such as steel mills or refineries."

One of the leading-edge technologies that is being tested and evaluated in collaboration with the Geological Survey of Canada is a permanent array of 650 geophones installed 20 metres deep within a 45-km2 area. Data will be transmitted via direct lines to equipment at the surface. "This will make it possible to monitor and track the CO2 plume in the reservoir," says Worth. "Tracking, monitoring and quantifying the movement of CO2 3.4 kilometres underground is definitely a key challenge."

The Japan Oil Gas and Metals National Corporation has also installed a permanent seismic source. "Typically, you need vibrating trucks or sources of energy—like dynamite—to record seismic, and it can be very expensive. Site and surface conditions can also impact the ability to obtain seismic readings. By having a constant seismic source near the site, we now have the ability to remotely control and acquire key data," explains Worth.

As part of the project, an observation well has been drilled 150 metres away from the injection well to help monitor any CO2 movement. The field data acquired will reduce the uncertainty of how CO2 acts when stored in deep geological formation. Here, too, technology is leading-edge. "The observation well has been fitted with fibre-optic acoustic sensor lines running on the outside of the casing and cemented in place," says Worth. "We are one of only a few wells in the world using acoustic fibre-lines, but it is applicable to industries other than CO2 storage. For example, oil and gas companies using high temperature or high pressure wells can deploy this technology to gather reservoir information."

Worth says that all the technology and equipment, including sensors that track what's happening at different formations within the reservoir and various surface installations, have been designed with one key objective: to enable PTRC to track, monitor and quantify how CO2 moves and acts in the reservoir. "Not only will our monitoring program track and monitor any changes in the reservoir all the way from 3.4 kilometres down to the surface, we are including regular groundwater and soil-gas surveys throughout the entire project within a 10 kilometre radius. If data indicates a need, we can customize and expand our area of investigation. We have also been monitoring groundwater in collaboration with local residents prior to CO2 injection and will continue to do so during injection to demonstrate that there has been no impact on groundwater."

There is also a patent pending down-hole fluid recovery system that will be operated by the University of Alberta. "This system will allow us to take samples of fluids right within the reservoir," says Worth. "It means we will now have an opportunity to confirm and improve predictive-simulation models.

"Together, these smart wells are two of the most sophisticated wells ever drilled in Saskatchewan," adds Worth. "Because we have drilled and logged these two wells as thoroughly as we have, we also have been able to fill a critical gap in understanding the geological characteristics of the area. There are very few wells drilled to this depth in the area. This data is now available to the public and could lead to further resource development in the area."

About 30 consultants and industry people are working on the project, with an additional 20 national and international researchers contributing expertise.

For more information, visit www.ptrc.ca or www.aquistore.ca.