Onshore / offshore monitoring focus of collaborative project
CMC Research Institutes and SINTEF Petroleum Research team up to advance integrated approach for monitoring geologically stored carbon dioxide
By Mark Lowey*
CMC Research Institutes has teamed up with SINTEF Petroleum Research in Norway to advance a new method for monitoring carbon dioxide geologically stored at onshore and offshore sites, such as the Norwegian Continental Shelf.
The three-year, CDN$4.4-million aCQurate project includes SINTEF testing its data integration method at CMC’s Containment and Monitoring Institute (CaMI) field research station. The new approach integrates and correlates multiple datasets from various types of monitoring technologies, to improve monitoring of injected CO2.
“The goal of the project is to reduce the risk of geological storage of CO2 by increasing the ability to verify where the CO2 is in the geological reservoir,” says Don Lawton, CaMI’s director and professor of geophysics at the University of Calgary.
“To further develop and field-test its new approach, SINTEF requires different types of geophysical data that you can only get from an onshore CO2 storage project like the one we have at CaMI.”
CaMI, owned and operated by CMC Research Institutes with operational funding from the University of Calgary, is located in Newell Country in southern Alberta.
Other collaborating organizations and research groups in the aCQurate project are: Statoil in Norway; University of Calgary; Lawrence Berkeley National Laboratory in California; INRS (Institut national de la recherche scientifique) in Quebec; GFZ (German Research Centre for Geosciences) in Germany; Quad Geometrics in Norway and the Scripps Institution of Oceanography in California.
“It is a significant project in terms of international collaboration,” Lawton says. “It shows that we are garnering high levels of international interest and participation in CaMI.”
CMCRI President and CEO Sandra Odendahl says the kind collaboration taking place through this project is key to reducing levels of CO2. “Climate change is a global crisis and we need to act quickly and together to develop and commercialize solutions. Because the Field Research Station provides multiple monitoring technologies it is ideal for bringing governments, industry and academics together to accelerate the development of best practices and technologies for carbon storage.”
CaMI “ideal” site for innovative R&D
The overall manager of the aCQurate project is SINTEF (Foundation for Scientific and Industrial Research) in Trondheim, Norway. SINTEF is the largest independent research organization in Scandinavia.
“What we’ve set out to do in the aCQurate project is to achieve accurate, quantitative and high-resolution monitoring of geological storage of CO2, which can be applied to large-scale onshore and offshore storage sites,” says Michael Jordan, senior research scientist at SINTEF.
The CaMI field research station has multiple surface and downhole monitoring technologies (see list at bottom of story) applicable to both onshore and offshore CO2 storage, he says. “I don’t know of any other sites where you have all these technologies co-located at the same time . . . it’s a very big advantage.”
Another advantage is that CaMI’s geological storage reservoir is relatively shallow, which means it’s not necessary to inject huge amounts of CO2 in order to detect and monitor changes in the gaseous CO2 plume and in the reservoir itself.
“It’s an ideal testing ground for developing our integrated hybrid joint inversion method,” Jordan says.
Getting the clearest picture of CO2 storage
Injecting CO2 into a geological reservoir changes the fluids and pressure in the rock formations, which affects the reservoir’s properties.
Seismic technology is widely used to monitor geologically stored CO2. While this provides detailed information about subsurface structure, seismic data alone doesn’t provide sufficient quantitative information.
For example, seismic data is insufficient for distinguishing pressure changes versus changes in the percentage of CO2 saturation within the reservoir.
“That is important to make sure that the pressure is not exceeding the critical pressure in the reservoir, so that you don’t damage your storage site,” Jordan says.
CO2 storage sites now employ multiple monitoring technologies, such as high-resolution seismic, electrical and gravity information. But often the data from these various methods are interpreted separately and look at only one aspect of the subsurface.
Since 2008, SINTEF has been developing its joint inversion approach for integrating various geophysical monitoring methods and datasets.
“The idea is to see the same subsurface from different viewpoints and make sure that the data we see from various monitoring methods, and the corresponding models of subsurface properties, are consistent with each other,” Jordan says. “The more information you can integrate, the less the uncertainty becomes.”
Ensuring effective and safe CO2 storage
Another driver of the aCQurate project is new regulations for CO2 storage sites, which require both containment assurance and conformance assurance.
Containment means being able to demonstrate that the storage site is performing effectively and safely. This requires monitoring pore pressure and formation strain in the reservoir to ensure the injected CO2 stays put, without migrating upward into another formation and potentially to the surface.
Conformance means the storage site is actually behaving as expected. “That means you have a consistency between what you predicted based on your models and what you observe,” Jordan says. This also requires monitoring various reservoir parameters, such as the CO2 saturation.
Measurement, monitoring and verification programs for CO2 storage sites also require determining the reservoir structure with high-resolution images and reliably characterizing the fluids and rock properties.
Integrating multiple monitoring datasets provides “a more accurate picture of what’s happening in the subsurface,” Lawton says. “The aim is to increase certainty of CO2 storage and verification of containment and conformance.”
Helping Norway meet its CO2 storage challenges
Norway has extensive experience with storing CO2 in geological structures, including two major projects operated by Statoil.
Since 1996, one million tonnes of CO2 have been separated each year from natural gas production in the Sleipner field in the North Sea, and stored in a geological formation 1,000 metres below the seabed. And since 2008, CO2 has been separated from the wellstream in the Snøhvit field at a liquefied natural gas facility on the island of Melkøya.
The Norwegian Continental Shelf has a significant storage potential that could be very valuable in a future European CO2 storage market. However, the geological complexity of reservoirs is a major challenge for CO2 monitoring strategies.
A particular challenge for Norway is the accumulation of CO2 within thin layers like those at Statoil’s Sleipner field.
Monitoring the subsurface of a large and deep CO2 storage site offshore requires multiple high-resolution seismic data. Integrating several methods on such a large scale poses significant challenges, including the immense computational cost, Jordan says.
The aCQurate project will create a new hybrid structural-petrophysical joint inversion method that will help to answer accurately and quantitatively: Where is the CO2? What is the pressure? What is the CO2 saturation?
As part of the project, Quad Geometrics and the Scripps Institution of Oceanography plan to apply for U.S. Department of Energy funding to develop and test at the CaMI site novel, highly sensitive tilt meters, to measure very small changes in deformation at the surface induced by CO2 injection.
Building international expertise
CLIMIT, Norway’s national program for research, development and demonstration of CO2 capture and storage technology, is providing 53 per cent of the aCQurate project’s total $4.4-million budget. Statoil is providing about $203,000, and the remainder is contributions-in-kind from the project partners.
More than 20 key personnel are participating among all the partners and collaborating organizations and research groups.
Key personnel include Jordan, Lawton and his UCalgary colleague Kris Innanen, associate professor of geoscience, and Amin Saeedfar, senior project lead at CMC Research Institutes, along with UCalgary graduate students and post-doctoral researchers. A post-doctoral researcher shared by SINTEF and GFZ also will be working at CaMI.
aCQurate is expected to lead to considerable development of expertise and technology in advanced geophysical monitoring of CO2 storage for the partnering countries of Canada, Norway, the United States and Germany. All the partners will have access to the integrated hybrid joint inversion approach.
If the new approach proves successful, it may become a preferred technology in new carbon capture and storage demonstration projects, which could be commercialized further with service companies.
Also, by enhancing monitoring and evaluation of geologically stored CO2, the project “may consequently help to increase public acceptance of large-scale geological storage and improve chances of reducing CO2 emission and meeting climate goals,” the project partners say.
Extensive suite of monitoring technologies at CaMI
Researchers at the CaMI field station already have deployed or will deploy and test an extensive suite of surface and downhole monitoring technologies, including:
- Seismic (bounces intense sound waves off underground rock structures to produce high-resolution seismic wave images of the geologic structure and reservoir properties);
- Controlled source electromagnetics (measures subsurface resistivity which can be used to quantify saturations changes in the storage reservoir due to the presence of CO2);
- Electrical resistivity tomography (measures electrical fields, or electrical resistivity. This is done either at the surface or with electrodes placed in well boreholes, to determine CO2 saturation levels in the reservoir);
- Gravity logs (Time-lapse gravity, which measures minute differences in the gravity field, is directly sensitive to the fluids in the pore-space, so it can be used to infer CO2 dissolution rates);
- Downhole gravimetry (measures the strength of a gravitational field, using instruments installed in well boreholes, to determine displacements in subsurface rock formations);
- Petrophysical data (measures the rock properties of the reservoir, such as pore pressure and strain);
- Distributed acoustic sensing fibre optics (uses distributed fibre optic cables as sensors to detect acoustic signals and measure strain in the reservoir);
- Magnetometric methods; (measures electrical resistivity changes to determine pore fluids and fluid chemistry due to injected CO2); and
- Tilt meters (measures and analyzes very small changes in deformation at the surface induced by CO2 injection).
*Mark Lowey is a professional journalist and science writer based in Calgary and managing editor of EnviroLine