Aquistore:  the World’s Most Comprehensive Industrial-Scale Field Laboratory for the Investigation of CO2 Geological Storage

Aquistore is Canada’s first deep saline CO₂ storage research project providing regulators and governments with the science-based facts and information necessary to develop informed policy and legislation surrounding the safe long term storage of CO₂ in the deep subsurface.

Aquistore is the buffer storage location for SaskPower’s Boundary Dam Integrated Carbon Capture Facility located in Estevan, Saskatchewan Canada, but the project’s field laboratory and research program have broad application for carbon storage across key industries like steel manufacturing, mining, cement production and chemical plants. The Boundary Dam facility has captured almost 1.5 million tonnes of CO₂ since it started operations in 2015, with the majority traveling via a 66 km pipeline to Cenovus Energy’s Weyburn oil field where it is used for enhanced oil recovery (EOR). CO₂ not required for EOR is pipelined 2 km away to the Aquistore well where it is injected into a brine and sandstone formation almost 3.4 km underground. As of March 31, 2017, over 107,000 tonnes of CO₂ have been stored at Aquistore.

With over C$45M in scientific monitoring installations at the Aquistore field site, Aquistore is the most extensively monitored CO₂ storage site in the world. The project’s measurement, monitoring, and verification (MMV) program incorporates surface, shallow subsurface, downhole, and seismic monitoring.

The field location includes the injection and observation wells, drilled 150 metres apart, to depths of 3.4 km each. A down-hole Fluid Recovery System (FRS) in the observation well is capable of recovering fluid samples from various depths underground. In addition, distributed temperature sensing (DTS fibre optic lines) in both the injection and monitoring wells are measuring subsurface temperatures. 3D seismic images of the injected CO₂ have been attained through several methods, including from a permanent array of 650 surface geophones, a vertical seismic profile (VSP), and distributed acoustic sensing (DAS) lines.

Since 2012 – prior to the start of injection in 2015 – the Aquistore program conducted electromagnetic surveys, well logs, seismic runs, and various assurance monitoring programs (groundwater, soil gas, atmospheric, microseismic, surface deformation) to provide baseline data for comparison with results recorded at various points since injection began. Results from the pre-injection MMV program are being compared with measurements conducted at various points between February and December 2016 to provide findings on the efficacy of different MMV methods and to help identify what work needs to be conducted in similar proposed storage projects going forward.

Results from seismic imaging has demonstrated, for the first time, that the CO₂ plume is clearly visible in the target formation at a depth of 3.2 km after just 36,000 tonnes of injected CO₂. Breakthrough of CO₂ from the injection to the observation well was also clearly indicated after analysis of fluids recovered using the FRS.

Findings from Aquistore are helping to define not only what MMV is needed for safe CO₂ geological storage across a broad range of industries, but is providing valuable insight into minimum datasets that are needed to establish and meet regulatory requirements for storage. With 30 monitoring technologies deployed at the site, discovering what is not needed for effective storage is just as valuable as what is.

Aquistore is expecting to conduct over 20 projects in the coming year (2017-18) in areas related to injectivity, capacity and conformance. Research and industry partners continue to join the program, with 34 collaborations and agreements already in place.