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IEA Greenhouse Gas R&D Programme

James-Craig cropThe Report documents the experience of 45 test injection projects from around the world, ranging in scale from a few hundred tonnes of CO2 to approximately 70,000 tonnes, with the objective of assisting countries or organisations wishing to embark on their first CO2 injection test. The majority of small scale projects have been undertaken in North America, with Australia and Japan, China and the European Union each having undertaken one or two small scale projects. Half of the projects are based on injection into sandstone reservoirs, although a significant 28% involve injection into coals. Only two test sites injected into basalt, the rest were carbonate reservoirs. Most projects injected less than 10,000 tonnes of CO2, with less than one-quarter of the projects injecting more than 10,000 tonnes. The depth of injection ranges from approximately 300m to over 4,000m but averages around 1,200m. The time taken from making the preliminary decision to undertake a project to injection of the first molecule of CO2 is variable but averages approximately three years.

Data sheets were compiled for each of the projects and a comprehensive summary database was developed as a prelude to the analysis of the similarities and differences between projects. A generic (industry-type) flow chart shows the development path that many projects have adopted, commencing with the development of the concept to final completion.

These small scale projects were undertaken for a variety of reasons. First and foremost they have provided valuable real world experience of CCS operations, to industry, government and researchers at a modest cost. They also provide an opportunity for stakeholders, including the broader community, NGOs and other interested groups to be able to visit projects and see operations at first hand. These demonstration projects provide clear evidence that governments and industry are pro-actively implementing measures to decrease CO2 emissions. They also provide opportunities to test new technologies, for example the detection of leakage, and to develop modelling capabilities.

Reservoir simulations are an important element of these injection pilots. They are used to design injection tests, predict plume and pressure behaviour and design an appropriate monitoring and verification scheme. Simulations can build confidence in the CO2 storage process by demonstrating that projects are thoroughly researched, well designed, and properly operated. In most published cases, the models provided a reasonable simulation of the CO2 storage process, particularly in the prediction of the pressure response during injection.

The report includes details of monitoring at different sites. Monitoring techniques are used primarily to monitor the pattern and progress of injected CO2 and identify any unexpected events that were recognised in a risk assessment. Deep saline aquifer storage more commonly utilises geophysical techniques, particularly seismic, to understand the areal distribution of the injected CO2. In cases where storage has been tested in depleted hydrocarbon fields, enhanced oil recovery (EOR) and enhanced coal bed methane (ECBM) sites, there is a much greater degree of understanding of geological conditions and most projects that fall into this category did not require extensive additional monitoring techniques. Geochemical monitoring was the dominant type of technique used to understand the performance of CO2 in depleted hydrocarbon fields or its behaviour in enhanced recovery processes (EOR and ECBM).

This valuable catalogue of small-scale test sites has revealed the extent of technology development and research related to CO2 injection and monitoring. These demonstration projects not only show that CO2 storage can be successfully achieved but they also lay the foundation for full-scale commercial CCS across the world.