Review of Offshore Monitoring for Ccs Projects
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REVIEW OF OFFSHORE MONITORING FOR CCS PROJECTS Report: 2015/02 July 2015 INTERNATIONAL ENERGY AGENCY The International Energy Agency (IEA) was established in 1974 within the framework of the Organisation for Economic Co-operation and Development (OECD) to implement an international energy programme. The IEA fosters co-operation amongst its 28 member countries and the European Commission, and with the other countries, in order to increase energy security by improved efficiency of energy use, development of alternative energy sources and research, development and demonstration on matters of energy supply and use. This is achieved through a series of collaborative activities, organised under more than 40 Implementing Agreements. These agreements cover more than 200 individual items of research, development and demonstration. IEAGHG is one of these Implementing Agreements. DISCLAIMER This report was prepared as an account of the work sponsored by IEAGHG. The views and opinions of the authors expressed herein do not necessarily reflect those of the IEAGHG, its members, the International Energy Agency, the organisations listed below, nor any employee or persons acting on behalf of any of them. In addition, none of these make any warranty, express or implied, assumes any liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product of process disclosed or represents that its use would not infringe privately owned rights, including any parties intellectual property rights. Reference herein to any commercial product, process, service or trade name, trade mark or manufacturer does not necessarily constitute or imply any endorsement, recommendation or any favouring of such products. COPYRIGHT Copyright © IEA Environmental Projects Ltd. (IEAGHG) 2015. All rights reserved. ACKNOWLEDGEMENTS AND CITATIONS This report describes research sponsored by IEAGHG. This report was prepared by: British Geological Survey, National Oceanography Centre, Plymouth Marine Laboratory, University of Southampton. The principal researchers were: Sarah Hannis, BGS Andy Chadwick, BGS Jonathan Pearce, BGS Dave Jones, BGS Jim White, BGS Ian Wright, NOC Douglas Connelly, NOC Steve Widdicombe, PML Jerry Blackford, PML Paul White, UoS Tim Leighton, UoS To ensure the quality and technical integrity of the research undertaken by IEAGHG each study is managed by an appointed IEAGHG manager. The report is also reviewed by a panel of independent technical experts before its release. The IEAGHG managers for this report were: James Craig and Tim Dixon The expert reviewers for this report were: Charles Jenkins, CSIRO Sue Hovorka, BEG, The University of Texas at Austin Aina Dahlø Janbu, Statoil Anne-Kari Furre, Statoil Marcella Dean, Shell Tim Dixon, IEAGHG The report should be cited in literature as follows: ‘IEAGHG, “Review of Offshore Monitoring for CCS Project, 2015/02, July, 2015.’ Further information or copies of the report can be obtained by contacting IEAGHG at: IEAGHG, Cheltenham Office Park, Pure Offices, Hatherley Lane, Cheltenham, GLOS., GL51 6SH, UK Tel: +44(0) 1242 802911 E-mail: [email protected] Internet: www.ieaghg.org REVIEW OF OFFSHORE MONITORING FOR CCS PROJECTS (IEA/CON/14/223) Key Messages A range of monitoring techniques are available for CO2 geological storage offshore, both deep- focussed (providing surveillance of the reservoir and deeper overburden) and shallow-focussed (providing surveillance of the near seabed, seabed and water-column). Deep-focussed operational monitoring systems have been deployed for a number of years at Sleipner, Snøhvit and also at the pilot-scale K12-B project in the offshore Netherlands, and conclusions regarding the efficacy of key technologies are starting to emerge. 3D seismic surveys have been highly effective for tracking CO2 plume development in Sleipner and Snøhvit reservoirs. Measurement of downhole pressure was crucial in establishing non-conformance at Snøhvit. A combination of 3D seismic and downhole pressure / temperature monitoring at Snøhvit has demonstrated the benefit of complementary techniques. Shallow-focussed monitoring systems are being developed and demonstrated. New marine sensor and existing underwater platform technology such as Automated Underwater Vehicles (AUVs) and mini-Remotely Operated Vehicles (Mini-ROVs) enable deployment and observation over large areas at potentially relatively low cost. Seafloor and ocean monitoring technologies can detect both dissolved phase CO2 and precursor fluids (using chemical analysis) and gas phase CO2.. Developments in geophysical techniques, such as the P-Cable seismic system for higher resolution 3D data collection in the overburden, have been demonstrated successfully and effective integration of these shallow subsurface technologies with the seabed monitoring data can help to understand shallow migration processes. Controlled release sites such as QICS1 have proved to be useful test-beds for shallow seismic techniques and acoustic detection systems. They can also reveal how CO2 migrates through, and is partially retained by, unconsolidated sediments. Monitoring strategies need to be devised to cover large areas, typically tens to hundreds of km2 and also achieve accurate measurement and characterisation possibly over lengthy periods. Limited spatial coverage could lead to the risk that anomalies remain undetected or are only detected after a lengthy period of time. Ameliorative measures might then be harder to implement. Search areas could be narrowed down by the integration of information from deeper-focussed monitoring such as 3D seismics, which can identify migration pathways, with shallow surface monitoring such as acoustic detection. Assessment of the results from both the operational (predominantly deep-focussed) and research (predominantly shallow-focussed) monitoring activities from Sleipner and Snøhvit indicates that many elements of the European storage requirements have been met at these large-scale sites which were both initiated before the CCS Directive was introduced. Background to the study Since the inception of CO2 injection into the Sleipner gas field in 1996 there has been considerable progress in monitoring offshore geological storage sites. There have also been recent developments, in-situ experiments, large-scale tests, and reviews on monitoring techniques for offshore monitoring applications. Some of these developments have occurred outside of the CCS sector. This is in addition 1 *QICS = Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage 1 to the deep monitoring for Statoil’s Sleipner project in the North Sea and Snøhvit project in the Barents Sea. In addition to technology developments there has been a corresponding series of regulations and related objectives which are designed to ensure that CO2 storage in offshore reservoirs can be retained within secure repositories without detrimental environmental effects. As with onshore CO2 geological storage, the objectives for offshore monitoring include: CO2 geological storage performance, baseline studies, leakage detection, and flux emission quantification. There are advantages and disadvantages of offshore monitoring compared to onshore. There is better and more consistent seismic coupling to the geology because of the water contact, there are less access issues in terms of landowners and infrastructure. In addition, emissions at the seabed can be both ‘seen’ and ‘heard’ as bubble streams. On the other hand, there are the challenges of working in a more remote and hostile marine environment. Sub-seabed geologic storage sites will have large spatial seafloor extent and large overlying ocean volumes (with potentially dispersed and localised emission sources) which provides a monitoring challenge. One requirement of any offshore leakage monitoring strategy development is to ensure wide area monitoring combined with sensitive detection thresholds. Potential CO2 leakage may have precursor fluid release of chemically-reducing sediment pore fluids and aquifer brines (each of which has a unique chemical signature). New marine sensor and existing underwater platform technology such as Automated Underwater Vehicles (AUVs) and mini-Remotely Operated Vehicles (Mini-ROVs) and seabed landers are under development to enable deployment and observation over large areas at potentially relatively low cost. Seafloor and ocean monitoring technologies can detect both dissolved phase CO2 and precursor fluids (using chemical analysis) and gas phase CO2 and seabed. Such chemical and physical monitoring systems may also provide tractable and robust methods for quantifying leakage loss beyond just detection. Developments in geophysical techniques, such as the P-Cable seismic system for higher resolution 3D data collection in the overburden, have been demonstrated successfully in the last few years and effective integration of these shallow subsurface technologies with the seabed monitoring data can help to understand shallow migration processes. Deep-focussed monitoring of reservoir and overburden has proved successful offshore, notably at Sleipner and Snøhvit. This study has reviewed and assessed the performance of these monitoring technologies and methodologies tools, and how new or modified tools might contribute to monitoring capability. Scope of work This report reviews offshore monitoring practice for CO2 storage projects in terms of tool capabilities, logistical practicalities and costs. The focus