10:15 - 10:45
Chalk reservoirs for upscaling CO2 storage
Subsurface storage of CO2 is a key enabler for Denmark to reach its short-term emission reduction goals. The scale of storage required to achieve significant reductions in emissions is orders of magnitude larger than the present project capacity. To address this challenge, new storage techniques are being explored, including the use of chalk reservoirs.
Chalk is a sedimentary rock that is composed of algal microfossils. Chalk is found extensively in Europe and Denmark and has several properties that make it appropriate for CO2 storage. The properties of chalk include high porosity and suitable permeability, which make it ideal for storing CO2.
Traditionally, CCS projects considered high permeability sandstone formations rather than chalk reservoirs due to concerns with regard to rock integrity in the presence of CO2.
Research at DTU Offshore, consisting of geomechanical and flooding experiments in the lab, and modeling, has demonstrated that there are no showstoppers to the use of chalk for CO2 storage. DTU Offshore is the prime knowledge center for subsurface-related research in Denmark, organized in a hub and satellite network with state-of-art test facilities, covering all aspects relevant to safe CO2 storage. Further ongoing research focuses on practical aspects of CO2 storage in chalk, aimed at reducing risks and improving operational efficiency.
Upscaling capacity is key to developing the right long-term solutions for Denmark. With the majority of Danish oil and gas fields being in chalk reservoirs, the reuse of these depleted chalk fields has the potential to significantly increase the scale of CCS options and contribute to the reduction of greenhouse gas emissions in Denmark and meet commitments made in the Paris Agreement.
