CO2 storage and oil production

Maximizing total oil production and making optimal use of the gradually depleting reservoir for storing CO₂

During oil production, only a part of the oil can be recovered from the reservoir. Injecting CO₂ into the oil field can improve the amount of oil production because the oil becomes more fluid and flows easier through the rock towards the production well. This method, which is called CO₂-Enhanced Oil Recovery (CO2-EOR), has been applied extensively for over 3 decades, predominantly in the USA but also in Hungary, Canada, Turkey, Brazil and Croatia. About three quarters of the CO₂ used in these operations comes from natural sources: it is produced from natural CO₂ reservoirs in the subsurface, and transported to the oil fields where it is sold to operators. As the delivery of this CO₂ is expensive, the amount used for the EOR process is minimized, while the oil production is maximized. Furthermore, at the end of the oil production, as much CO₂ as possible is produced back for re-use in adjacent oil fields. Such an operation does not result in CO₂ emission reduction.

In the ENOS project we will investigate how the use of man-made CO₂, captured at power plants or industrial facilities, for example, can be combined with CO₂ storage for climate change mitigation, together with reducing the cost of CCS projects. Classical CO₂-EOR projects are not designed specifically for CO₂ storage, and thus research is needed to optimise the oil recovery, while, at the same time, maximising the amount of CO₂ stored in the reservoir. This way, the economic benefit of enhanced oil recovery can be combined with the ambition to reduce CO₂ emissions.

The Czech LBr-1 site will be used as a demonstration for developing techno-economic evaluations of this concept. CO₂-EOR processes will be modelled using real data from the site and lab experiments. Different options for the necessary infrastructure, including inexpensive flexible wells, will be considered. A detailed plan for a field-scale CCUS (Carbon dioxide Capture, Use and Storage) pilot at LBr-1 field will be developed. Economic issues and challenges will be studied to identify value ranges of costs and benefits, taking into account a wide range of factors that come into play in real-world projects. Finally, regulatory aspects will be investigated in the context of national legislation, with a focus on the definition of the storage complex and on cross-border issues, since the LBr-1 site is situated close to the Czech-Slovak border.

Outcomes

A developed approach combining EOR and storage aspects based on both technical, economic and regulatory factors for the LBr-1 field. While the end result would be field-specific, the developed approach will lay a basis for the roadmap and for a guidance document (best practice).