Special Core Analysis for the CMC-FRS

In this project we are working with Carbon Management Canada to analyse rock samples obtained from their Field Research Station. In the laboratory at Imperial College we analyse how CO₂ and salty water flow through the rocks at conditions similar to what will occur in the subsurface when CO₂ is injected.

In July 2016 we headed out to the Carbon Management Canada Field Research Station to review the rock core material and carefully select cores for multiphase flow characterization back in the lab. We were generously hosted by Don Lawton and Kirk Osadetz of Carbon Management Canada.

We spent most of the first day at the Alberta Core Research Centre which contains a comprehensive archive of rock cores from wells drilled in Alberta. Given the importance of oil in the province, the centre is an impressive place, boasting over 1.5 million boxes of core, organized and accessible for inspection and analysis 

The Field Research Station has obtained approximately 300m of core from one of the wells that will later serve as an injection well for CO₂. At the Core Research Centre we were able to lay out the entire core length (Figure 2). While that is far more than is needed for sampling, it provided excellent context for understanding the local stratigraphy, and potential conduits to flow and trapping of the released CO₂.

The first injection test is targeting a thin sandstone formation known informally as the Basal Belly River sandstone. This is about 5m thick and represents a relatively homogenous unit for injection (Figure 3). At 1 mD, it is higher permeability than the overlying and underlying rock units, but it is still at the very low end of permeability for rocks that we have worked with before.

The sandstone interval is around 300m underground. This is not as deep as CO₂ injection for industrial scale storage and it is expected that the CO₂ will remain in the gaseous phase as it is injected. This is ideal for studying how CO₂ might flow in overburden layers, were it to leak from a primary storage reservoir target, a key uncertainty in our understanding of subsurface storage. Additionally, the thin interval of sandstone provides an opportunity to study CO₂ flow at larger scales than can be observed in the laboratory, while still minimizing the complexity of the system. This is an ideal setting in which to test our procedures for characterizing rocks and our models for flow.  

The injection and monitoring wells are all within 100m of each other (Figure 5). The sparseness of the surface infrastructure hides the complexity of what will occur in the subsurface once CO₂ is injected! 

After a visit to the injection site, the field trip heads to the nearby UNESCO World Heritage Site Dinosaur Provincial Park (Figure 6). In addition to the beautiful scenery, there are walks amidst fossil excavation areas, and a great dinosaur museum. 

Another fantastic side trip included a visit to the Calgary Stampede (Figure 7). This is a county fair and rodeo packed into one giant extravaganza. Calgary is widely known for the annual fair and there was a festive vibe throughout the city. 

Back in the lab, the painstaking analyses of rocks have begun (Figure 8). These particular rocks require extra care because of their low permeability and the presence of clays which can swell if the rock comes in contact with fresh water. The first observations of relative permeability and residual trapping will take place this summer, and the collaboration with Carbon management Canada continues, all thanks to the starter grant from the UKCCSRC.