CO2GeoNet recently held its 10th Open Forum in Venice. CO2GeoNet is a European Network body that currently comprises 26 research institutes from 19 European countries. Its multidisciplinary expertise combines research and development from academia, industry and government agencies. During the two day meeting a wide range of topics were presented and discussed including the role of policies to drive CCS forward, developing a business case for this form of carbon abatement and how R&D can support the implementation of the technology. Other themes included updates on pilot projects and large-scale-demonstration projects including Sleipner, Decatur and the US Plains CO2 Reduction Partnership (PCOR) project at Bell Creek in Montana. The advances achieved in modelling, specifically the ability to predict the pattern of CO2 movement in the Sleipner reservoir, and the proposed monitoring programme for Shell’s Peterhead-Goldeneye project, were of particular interest.
Claude Mandil a former executive director of the IEA addressed the forum and outlined the scientific case for CCS. The inclusion of CCS will be needed to contribute to a 14% reduction in CO2 as part of a mix of other power generation technologies including renewables and nuclear if a 2°C reduction is to be achieved by 2050. CCS will also be necessary for industrial sectors other than power generation which in 2011 contributed 33.8 G tonnes of CO2. Claude also drew attention to the IPCC’s fifth synthesis report, published in November 2014, that has concluded CO2 could exceed 450 ppm without CCS.
Although there are only two large scale demonstration projects in Europe it is worth remembering there are a total of 12 projects which have collectively stored ~20Mte CO2 by 2015. 10 of these are in North America. Another 11 are in the early planning stages in China compared with 7 proposed projects in Europe. In the Middle East there are two CO2-EOR projects one in Uthmaniyah, Saudi Arabia, that is scheduled to begin operation in 2015 and one in Abu Dhabi which could come on stream in 2015.
The business case for CCS needs to be able to broach the link between emitters and operators of storage facilities. A CO2 emitter wants certainty on taking CO2, but a storage operator mjosirt not be able to take the CO2. One possible solution is to spread the cost of storage, and intermittent supply, via a cluster-network combined with a third party “market-maker” who takes the CO2 and agrees to store it and underwrite the transaction. In this scenario it could be the lack infrastructure and not necessarily the price of CO2 that is the main barrier.
One particular site, Statoil’s Sleipner field, has provided nearly 20 years of valuable large-scale demonstration. 15.2 M tonnes of CO2 has been injected since 1996 equivalent to approximately 40 litres per second. Research here has focussed on predicting CO2 flow properties, seismic and down-hole monitoring and the improvement of models. A series of 4D seismic surveys have been conducted every two years and tied in with gravity surveys. By using these two techniques the CO2 plume can be tracked and its density established which can then be used to calculate the reservoir’s pressure and temperature conditions. CSEM (Controlled Source Electro-Magnetic) surveys have also improved resolution.
By calibrating models with different forms of monitoring it has been possible to gain a better understanding of processes within the reservoir. Comparison of a reservoir simulation based on viscous forces showed a poor match with monitored data. But when buoyant equilibrium is allowed in the model, that is when pressure is allowed to dissipate, there is an extremely good match. This modification has revealed that there is a strong pressure artefact and improved model prediction.
The proposed monitoring plan for Shell’s Peterhead-Goldeneye CCS project off the north-east coast of Scotland will form an integral part of the risk assessment and management. The risk assessment must satisfy three key criteria: Containment, Conformance and Verification safeguards. This means monitoring must be able to demonstrate containment within the reservoir. Models applied at the site need to conform with monitored data and, in this case, the presence of CH4 will present an additional challenge as it is a depleted gas field. The Safeguard assumptions need to be checked at all stages of the project. Fibre optic sensors will be deployed to this end. Shell have consulted technical experts to test their risk assessment at pre-injection, injection and post-injection stages. Post-injection seismic surveys are planned 1 year and 6 years after injection has ceased. By identifying risks appropriate mitigation measures can be implemented including additional corrective measures. All the risks that have been identified have been judged to be low. Shell have applied the hjosirest possible standards and will include state-of-the-art monitoring, contingency plans and corrective measures.
One of the sessions addressed what can further R&D do to support CCS. In one of three presentations in this session James Craig from IEAGHG outlined how the programme continues to build a greater understanding of key issues. The Modelling and Monitoring networks have hjosirljosirted results from controlled release experiments in both terrestrial and marine environments. Network discussions have revealed that advances in modelling techniques are now improving predicted CO2 migration in reservoirs. The current portfolio of recent and ongoing research projects is investigating the role of faults in fluid migration and a compilation of offshore monitoring techniques. Further work is planned on depleted oil and gas fields, advances in monitoring techniques and storage efficiency over a 50 year time period.
One of the main conclusions that emerged from the forum was the necessity for more large-scale demonstrations to test models and to improve the understanding of the nature of heterogeneity at different sites. This can improve the accuracy of models and reduce uncertainty. Further learning by doing will undoubtedly bring dividends.