Work Packages

This work package describes the subsurface studies necessary to confirm the potential for CO₂ storage in the Harald East chalk reservoir. Chalk is the predominant lithology for hydrocarbon fields in the Danish North Sea, however for CO₂ storage purposes, chalk is seen as a less mature lithology than sandstone. CO₂ storage in Harald East chalk would bring additional storage potential to Bifrost. Additionally, these studies could unlock a much larger CO₂ storage potential in chalk in the Danish North Sea. 

This work package builds on a State-of-the-Art study conducted by DTU Offshore and published in the report “CO₂ storage in Danish Oil & Gas fields”, December 2020 (link to executive summary of the report in Danish here) and later published in the paper “Challenges and enablers for large-scale CO₂ storage in chalk formations” (Bonto  et al. 2021; link: doi.org/10.1016/j.earscirev.2021.103826). The report and paper provide a State-of-the-Art summary for CO₂ storage in existing offshore DUC oil and gas chalk reservoirs and maps the knowledge and technology gaps that will be important to address for a dedicated CO₂ storage project in Danish chalk to become feasible.

This work package is dedicated to the design of Harald West wells upper and lower completion, ensuring consistency with reservoir injectivity and surface constraints under the assumption of a continuous injection flow of non-cryogenic pressurized CO₂ at the wellhead. These injection conditions do not bear the shortcomings of batch CO₂ injection which results in frequent expansion of CO₂ during injection stops and the associated extreme low temperatures that pose threats to well integrity as well as flow assurance specific problems and operating challenges. The range for injection pressure conditions will be considered in coordination with subsurface work (WP03) to cover the anticipated re-pressurization of the reservoir during the life of the project.

This work package investigates the feasibility of a CO₂ transportation and injection chain aiming at a continuous injection of CO₂ via two platform wells into the Harald West reservoir. This chain comprises a fleet of medium pressure cryogenic shuttle tankers for offshore offloading, a floating unit for CO₂ buffer storage and conditioning for injection, and integration modifications on the Harald West facilities.

This work package is dedicated to the screening and selection of ship design and interface with the New Offshore Offloading Facility described in WP6. 

The work performed capitalizes on experience gained from on-going projects – Northern Lights (Norway) and Aramis (the Netherlands). While ships for those projects are designed for onshore loading and onshore offloading, some incremental work is nevertheless required to assess suitability and potential design modification for offshore offloading in the frame of the full offshore concept studied in WP6. 

Dynamic positioning capacities and bow off-loading requirements are key elements that are being investigated.

The re-use of existing pipelines is a key lever to optimize costs and reduce carbon footprint. Bifrost studies the potential re-use of the existing offshore hydrocarbon pipelines operated by Ørsted. The CO₂ transported by ship would be offloaded at an onshore receiving terminal equipped with offloading facilities, buffer storage and compression stations to condition CO₂ in dense phase before transportation through the offshore pipeline to the Harald West facilities.​

The new facilities and modifications to existing facilities investigated for project Bifrost shall be designed such that methods of risk reduction commonly used to ensure acceptable HSE performance and qualities are inherent in design, construction, commissioning and operation. 

This is being done through: 

• Implementing high HSE technical standards
• Defining permit and consent register in compliance with regulations in place​
• Performing Environmental and Societal desktop study and SENVID study to identify social and environmental potential impact 

Monitoring of geological storage facilities, from pre-injection baseline surveys to final handover of the facility to authorities, is central to demonstrating safe and permanent containment, to prevent and mitigate potential leakage, and to build public acceptance. Identifying the right monitoring technologies is therefore key to the success of any CCS project. This work package includes activities to develop a CO₂ monitoring strategy for project Bifrost to prepare for the elaboration of an actual monitoring plan:  

• Review of ‘state-of-the-art’ within monitoring, measurement and verification (MMV) for offshore CO₂ storage projects world-wide
• Development of concept for monitoring CO₂ injection and storage in the Harald reservoirs – closely linked to the subsurface understanding gained from WP3 and WP4
• Maturation of two new innovative monitoring technologies at DTU Offshore, including highly sensitive, stationary, specific chemical sensors for continuous monitoring of the storage site, and a monitoring digital twin concept, utilizing an advanced machine learning method to optimize prediction of CO₂ plume migration

Acceptance of energy technologies are crucial in the green energy transition and lack of acceptance can be a game-stopper. Acceptance is strongly related to the perceived benefits (CO₂ reductions, employment effects etc.) and costs/risks (leakages, environmental impact, and high costs etc.) associated with technologies. If the costs out-weights the benefits, people tend to dislike technologies. WP11 analyses the benefits and the costs of CCS and tests how benefit and cost information influence acceptance of, and preferences for, CCS. 

The objectives are: 

• To estimate the economic effects of CO₂ storage on the Danish economy
• To gather and analyze perceptions and acceptance of carbon storage among key stakeholders
• To gather and analyze perceptions, acceptance of – and preferences for CO₂ storage among the Danish general population and specifically targeted groups

A national survey reaching 50,000 Danish households and with over 8,000 respondents has been carried out together with dedicated stakeholder interviews to assess the perception & acceptance of CCS in Denmark. An additional survey is in the pipeline. Results of this will follow.