DiSECCS: Diagnostic Seismic toolbox for the Efficient Control of CO2 Storage

The year 2011 recorded the highest ever global consumption of energy, estimated at more than 12 billion tonnes of oil equivalent. Because of this, and despite increasingly widespread deployment of renewable energy generation, annual global emissions of greenhouse gases are continuing to rise, underpinned by increasing consumption of fossil fuels. Carbon capture and storage (CCS) is currently the only available technology that can significantly reduce CO2 emissions to the atmosphere from fossil fuel power stations and other industrial facilities such as oil refineries, steel works, cement factories and chemical plants. However, achieving meaningful emissions reduction requires wide deployment of large scale CCS and will involve long term storage of very large volumes of CO2 in the subsurface. Ultimately, if CCS were to be rolled out globally, volumes of injected carbon dioxide could become comparable, on an annual basis, to world hydrocarbon production.

The most likely sites for CO2 storage are depleted oil and gas fields or saline aquifers. Understanding and monitoring geomechanical processes within different types of storage site is crucial for site selection, for achieving long term security of storage and for instilling wider confidence in the safety and effectiveness of CCS. In many cases depleted hydrocarbon fields have experienced strong pressure decrease during production which may have affected the integrity of the caprock seal; furthermore, CO2 injection into saline aquifers will displace large volumes of groundwater (brine). In all cases, as injection proceeds and reservoir pressures increase, maintaining the geomechanical stability of the storage reservoir will be of great importance. Understanding and managing these subsurface processes is key to minimising any risk that CO2 storage could result in unexpected effects such as induced earthquakes or damage to caprock seal integrity.

Experience from existing large-scale CO2 injection sites shows that monitoring tools such as time-lapse 3D seismic, micro-seismic monitoring and satellite interferometry have the potential to make a significant contribution to our understanding of reservoir processes, including fine-scale flow of CO2, fluid pressure changes, induced seismic activity and ground displacements. The DiSECCS project will bring together monitoring datasets from the world's three industrial scale CO2 storage sites at Sleipner (offshore Norway), Snohvit (offshore Norway) and In Salah (Algeria) to develop and test advanced and innovative monitoring tools and methods for the measurement and characterisation of pressure increase, CO2 migration and fluid saturation changes and geomechanical response. A key element of the research will be to identify those storage reservoir types that will be suitable for large-scale CO2 storage without unwanted geomechanical effects, and to develop monitoring tools and strategies to ensure safe and effective storage site performance.

In addition, our research will explore public attitudes to CO2 storage. We will consider what insights may be drawn from previous proposed CCS schemes involving onshore storage and other activities that have aroused similar concerns (such as earthquakes associated with shale gas fracking near to Blackpool) and how this experience can inform proposed large-scale offshore storage operations in the future. In the past, public opposition to some onshore storage proposals has led to project delays and cancellation, for example, in the Netherlands, Denmark and Germany, and research has identified storage as the stage in the CCS chain that has most potential for concern to members of the lay public. Developing an improved understanding of potential societal responses to CO2 storage and monitoring is crucial for establishing a sustainable and successful CCS strategy; this research will contribute to this through a combination of case study analysis and participatory research with lay citizens.

Carbon Capture and Storage (CCS) has been identified by DECC and the UK government Committee on Climate Change as pivotal to achieving the UK's CO2 emissions targets in the coming decades. For CCS to be deployed safely and to its full potential, it is essential to ensure reservoir containment integrity, to utilise the best storage reservoirs with optimal efficiency and to properly understand the extent of realistic storage capacity. The DiSECCS project has been designed to address these key issues and aims to achieve impacts in a number of ways.

Long term beneficiaries will be global populations and their governments who need large-scale implementation of CCS over the next 10 to 50 years to help reduce societal and economic impacts from climate change and to facilitate a managed transition from carbon-based to low-carbon energy economies. The insurance industry will also benefit from this in the longer-term.

The main direct beneficiaries of DiSECCS research will be industrial emitters of CO2 who will face caps on their permitted emissions in line with national targets; storage operators who will have to run their storage sites in accordance with national and international regulatory requirements (e.g the EU Storage Directive); national authorities responsible for permitting and regulating storage; and government policy-makers who need have robust estimates of national storage capacity for strategic planning reasons (in the UK this would include DECC and the Crown Estate). To this end, on our Stakeholder Panel we have DECC-EDU, responsible for regulating CCS in the UK, and two major oil companies currently engaged in large-scale CCS in Europe and beyond. We hope to extend our Stakeholder Panel further by inviting the successful projects in the UK CCS Commercialisation Programme to join. We are also in discussions with a leading CCS scientist from the Canadian government to join the Stakeholder Panel (Canada is currently leading the way towards deployment of full-chain CCS via a number of projects in Alberta and Saskatchewan). (Note the above impacts are applicable both to the UK and internationally).

The UK, along with Norway, controls Europe's principal CO2 storage resource in its offshore basins. Large-scale rollout of CCS therefore provides the possibility of storing CO2 from other European countries, opening up major additional financial opportunities for the UK, with direct benefits to the UK Treasury. More specifically, DiSECCS research involves unique and innovative elements and can underpin developments of niche UK technical capabilities in CCS. These have the potential to develop business opportunities worldwide [an analogous situation emerged in 2010 when BGS specialist shallow monitoring teams were employed by the Weyburn CO2-EOR project in Canada to test and refute leakage claims]. The applicability of DiSECCS science moreover extends well beyond CCS. It is closely relevant to time-lapse monitoring of UK hydrocarbon production particularly those fields utilising fracture permeability and is of direct application to improving 'fracking' methodologies, such as for shale gas exploitation. It is important to exploit these domestic resources to their full potential for energy security and economic reasons and this element of the research will be of particular interest to companies with an interest in fossil fuel production.

Social research in DiSECCS will examine controversial aspects of all underground injection activity and aims to contribute to improving the CCS industry's approach to societal concerns and help promote public confidence in future storage projects.