REX-CO2 will increase the technical feasibility and economic competitiveness of high-potential depleted hydrocarbon fields earmarked for CO2 storage.

Contracting Authority: UEFISCDI
Contract number: 122/1.09.2019
Project manager: Dr. Alexandra-Constanța DUDU

Documents:

• Raport REXCO2 etapa 1 2019 GeoEcoMar_final.pdf

Existing oil and gas industry installations which cover large parts of the potential CCS chain are already in place, and an increasing number of reservoirs have come to the end of their production lifetime and are earmarked as major targets for initiating large-scale CCUS operations (DOE, 2017). The existing wells in these assets present both opportunity and challenges. Substantial savings could be realized by re-using these wells as CO2 injectors, monitoring wells, or for water production (pressure management). On the other hand, the existing well infrastructure poses a risk as a potential CO2 or brine leakage pathway (Watson and Bachu, 2009). In this project, we take a fresh look at this problem and provide a novel solution. The re-use of wells is the inverse of the problem of identifying defective wells. The process of certifying well integrity can also be used to identify wells suitable for continued use in a CO2-rich environment. We develop a qualification process that will simultaneously save CO2 storage projects money and time by identifying existing infrastructure that is seif to re-use, while determining which wells must be remediated to ensure long-term storage.

Re-use can benefit projects in all geological settings but may be particularly crucial for off-shore environments, such as the North Sea or the Gulf of Mexico, where well development costs could otherwise be prohibitive. Developing a procedure and tools for evaluating the reuse potential of existing hydrocarbon fields and wells will require a dedicated investigation encompassing the interrelated technical, environmental, economic and social aspects. Currently no such publicly available tool exists. For this project, we conduct the necessary research to develop a dedicated well-screening tool for Reusing EXisting Wells for CO2 storage operations (REX-CO2).

Objectives

• Develop a publicly available well reuse screening tool which helps stakeholders to make informed decisions on the CCS reuse potential of certain wells or fields;
• Demonstrate the application of the developed tool to perform dedicated reuse assessment, including technical, ecological and economic aspects with candidate wells/fields from multiple international sites;
• Perform laboratory testing on relevant reuse risk scenarios, provide recommendations for (smart) material selection in reused wells; feed coupled thermo-hydraulic-mechanical-chemical (THMC) models and improve failure predictions;
• Provide guidance for the development of reuse permit applications;
• Gain an improved understanding on public acceptance and provide guidance on the socio-economic aspects of re-using oil and gas infrastructures.

Expected results

The results of REX-CO2 are expected to facilitate large-scale CCUS implementation by providing a tool to evaluate and rank the CO2 reuse potential of hydrocarbon fields. The developed technology is not limited to a particular sector of CO2 storage but will accelerate all types of CCS. Key results will include:

• Synthesised findings from developing a public reuse well screening tool for reusing existing hydrocarbon fields
• Key findings in laboratory experiments , including well cement state of stress, material self-healing potential and implications for integrity of
reused wells
• Field scale numerical simulation results for different reuse field scenarios
• Field case reuse studies for selected wells and depleted fields in all six partner countries
• Assessment of public acceptance and recommendations for future projects involving well re-use for CO2 injection/storage
• Development of technical and socioeconomic best practice recommendations for reusing existing wells for CO2 storage