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The UK GeoEnergy Test Bed (GTB) is a field research platform initiated by the British Geological Survey and University of Nottingham. The GTB will be used to undertake research to refine strategies and tools for monitoring the zone above CO2 storage reservoir; an essential part of proving site conformance. Research at the GTB will support the emerging CO2 storage industry by enabling testing of innovative sensors and advancing understanding of fluid migration in the shallow subsurface, which will in turn enable more effective monitoring strategies for large-scale storage sites. The GTB comprises an array of above surface and subsurface sensors focused on two CO2 injection wells, one deep (~212 m) and one shallow (~12 m). A permanent sensor array (plus intermittent mobile surveys) will be used to study the acoustic, electro-magnetic, mechanical, geochemical and other relevant properties of the volume of rock and pore fluids around the injection wells, and CO2 levels in the soil and air. The first CO2 injection is planned during 2021. The GTB offers a unique facility in the UK to study CO2 migration at a location where rocks have not previously been exposed to significant quantities of CO2.

Monitoring of geological CO2 storage is crucial for large-scale injection to gain public acceptance. Monitoring plans for large-scale operations need to include both the injection and post-injection phases to assure CO2 is safely stored permanently. The SENSE project aims to develop reliable, continuous, and cost-efficient monitoring based on ground movement detection combined with geomechanical modeling and inversion, utilizing new technology developments, data processing optimization, and interpretation algorithms. The proposed research activities include: • demonstration of continuous monitoring of surface deformation and subsurface pressure distribution using satellite data, water pressure sensors and fiber optics; • quantitative characterization of critical geomechanical and hydraulic parameters and automatization routine for data processing and interpretation; • optimization of sampling arrays in order to offer storage site operators a cost-effective monitoring option as part of an effective site assurance program. The SENSE project brings together experts from 14 international institutions of nine different countries to solve challenges in CO2 storage site monitoring and to provide solutions for safe and successful injection and post-closure phases of site operation. The project is organized in five Work Packages (WPs); WP1: Quantification of ground movement, WP2: Geomechanical modeling and rock strain assessment, WP3: History matching inversion and coupled flow-mechanics, WP4: Integration of results for cost-effective monitoring and WP5: Project management. The ultimate goal of SENSE is to offer storage site operators a cost-effective monitoring option that can form part of an effective site assurance/monitoring program and feed into workflows for an early alert system to detect unexpected changes in the subsurface. The SENSE project has four demonstration sites for monitoring technologies and developing concepts and procedures. These sites are both onshore and offshore. The onshore sites include In Salah (Algeria) and Hotfield Moors (UK). For these sites, the project will use satellite data to explore the response of the surface to pressure changes in the subsurface. Algorithms for automatic satellite data processing to facilitate quick access to ground elevation data for site operators are under development at the British Geological Survey (BGS) and Norwegian Geotechnical Institute (NGI). The offshore sites include Bay of Mecklenburg (Germany) and the Gulf of Mexico (USA). In addition, the SENSE partners have requested access to data from the Troll Gas Field, the North Sea, to study its subsidence due to production-related pressure reduction. The Troll Gas Field is located next to the storage site considered for the Norwegian Long Ship project, and its data will provide a good understanding of the geomechanics of the area. In this paper, we present the work on the In Salah and the Bay of Mecklenburg sites. New InSAR data from the In Salah are used to evaluate the ground movement during the post-injection period and thus to assess the behaviour of the storage site after completion of the injection phase. Bay of Mecklenburg is an offshore site for field experiment to inject a gas underground, build-up pressure, uplift the seafloor and measure the resulted uplift. The first field campaign at the Bay of Mecklenburg was completed in late 2019. It provided both gravity cores from the seabed and geophysical data acquisition for characterizing the shallow subsurface layers. The gravity cores were characterized for physical and mechanical properties. The material properties were used for simulating injection and response of the seafloor to induced pressure. Geomechanical 2D and 3D simulations show that the reservoir may sustain very low overpressure before it fails. Hence, this magnitude of overpressure may create a seafloor uplift of about a few millimeters to a couple of centimeters. The monitoring techniques are therefore being designed to capture uplift in this order of magnitude during the injection operation.

Carbon dioxide capture and storage (CCS) is an effective technology to reduce carbon dioxide (CO2) emissions in China. In this paper, the authors considered storage opportunities offered by oil reservoirs and deep saline aquifers in the Jiyang Depression, in east China. Based on detailed geological analysis and assessment of CO2 storage suitability, the Dongying Sag and Linyi‐Shanghe areas of the Huimin Sag within the Jiyang Depression appear promising for CO2 storage. Following more detailed characterization, the second and third members of the Shahejie Formation located in these two areas appear the most promising for CO2 storage. Within the areas identified as having potential for storage, 55 primary and 62 secondary recommended storage units were defined, with a total theoretical capacity of 5.02 × 108 tonnes (t) CO2. This represents storage of CO2 emissions from large‐scale sources in the Jiyang Depression for more than 30 years at current emission rates.

The existence of an extensive, prospective Visean–Namurian Carboniferous petroleum system in and around the hitherto under-explored Mid North Sea High is documented. Evidence is drawn from integrated analysis of over 50,000 line kilometres of seismic data and well data, together with regional source rock screening, reservoir analysis and basin modelling. Visean-Namurian marine and non-marine mudstones and coal source rocks are interbedded within fluvial and marine reservoir sandstones within a stacked succession up to 5 km thick. Source rocks are dominantly gas-prone with oil-prone intervals, and have reached oil to gas maturity levels dependent on location. Burial/thermal history modelling indicates a kitchen area on the southern margin of the Mid North Sea High with northwest and northeastwards migration of gas and oil during Mesozoic and Cenozoic times. A variety of structural and stratigraphic traps are possible, including intraformational Carboniferous traps, with a regional seal at Permian (Zechstein) level. Synthesis of many previously unpublished datasets demonstrates the Visean–Namurian play south of the Mid North Sea High as part of an extensive petroleum system from the East Irish Sea, across onshore to offshore UK and into The Netherlands sector of the North Sea. The purpose of this synthesis is to highlight future exploration opportunities beneath and northwards of the productive Westphalian Southern North Sea gas basin, and to begin to de-risk the petroleum systems that are exemplified by the lower Carboniferous Breagh Field in a frontier area of the mature North Sea province.

As a UNFCCC accredited Research NGO, CO2GeoNet has been deeply involved in bringing the science behind CO2 storage and the rationale for Carbon dioxide Capture and Storage (CCS) to a wide range of stakeholders (including the general public) before, during and after the COP21 Climate Conference in Paris. Key messages on CO2 storage, informed by dialogue with numerous stakeholders, are presented here. The overarching conclusion is that collaboration is needed at an EU and a global level to deploy CCS, a viable and flexible technology ready to play an essential role in completing the climate change mitigation portfolio.

A survey to evaluate the main perceived barriers to national CO 2 storage assessments was carried out in 2015, targeting countries where some Carbon dioxide Capture and Storage (CCS) activity was known or where CCS could potentially be implemented in the future. All the questionnaire respondents indicated that some level of national assessment had been achieved. In most cases, these assessments had been sufficient to allow policy makers to make informed decisions about priorities for follow-up actions. Where national storage assessments had been carried out, the major barriers had been mainly overcome through strong political and regulatory support for CCS and policies enabling access to relevant data.

Summary The GeoEnergy Test Bed (GTB) is a research facility initiated by the British Geological Survey and the University of Nottingham comprising an instrumented borehole array. The site represents a £6M investment to support new and emergent geo-energy sectors critical for a sustainable energy future.

To meet the ambitious target set out in the Paris Agreement to keep the temperature rise well below 2°C, all the tools available for reducing CO2 emissions, including CO2 Capture, Utilisation and Storage (CCUS), are needed to meet the challenge. Global collaboration is key in advancing CCUS. CO2GeoNet, a pan-European scientific body on CO2 geological storage, has gained visibility and recognition in the European and global arenas, participating in research and providing scientific advice, training and capacity building, and information and communication. A summary of CO2GeoNet’s cooperation activities with countries outside Europe and with international bodies is given here. CO2GeoNet is open to further opportunities as the Association views global cooperation as critical to accelerating the development, recognition and deployment of CCUS as an important and flexible climate change mitigation technology.

Summary The UK GeoEnergy Test Bed (GTB) is a field laboratory founded by the University of Nottingham and The British Geological Survey (BGS) for subsurface research into fluid migration through natural pathways. The GTB was initiated with funding from the founding partners and has received capital investment from the UK Government’s Treasury as part of the Energy Research Accelerator (ERA) project. The GTB will act as a research hub to catalyse scientific collaboration between researchers from academic and industrial backgrounds. The aim of the GTB is to advance geoscientific research to support the global need for secure, sustainable and safe energy. Geophysical, geochemical, petrochemical and hydrogeological data have been collected during site characterization and used to build a conceptual geological model. Permission is being sought from the relevant authorities to inject a small amount of food-grade CO2. Surface and downhole technologies and techniques will be used to monitor site behaviour before, during and after fluid injection. The sensing capability at the GTB has been designed by the BGS to enable interrogation of the subsurface in 4D and to a level of detail commensurate with energy processes in the subsurface.

Carbon dioxide capture and storage (CCS) is the only technology currently available that can significantly reduce carbon dioxide (CO2) emissions from conventional fossil fuel use. Depleted oil/gas fields, unmineable coal seams, and deep saline aquifers are generally considered to be the main storage options. In this paper, the authors consider opportunities presented by aquifers close to hydrocarbon fields in the northern Songliao Basin (China) for storage. Data obtained during exploration and production often delineates nearby structures filled with saline water which have not been charged with hydrocarbons but could offer an opportunity for CO2 storage. Based on published data and production data from hydrocarbon fields in the northern Songliao Basin, the potential for geological storage of CO2 in these hydrocarbon field saline aquifers (HFSA) has been assessed and in the northern Songliao Basin, the central and western regions offer great potential for CO2 storage in HFSA. Out of the 42 identified oil/gas fields, aquifers near 24 of the fields offer promising storage potential with an estimated potential storage capacity of 9.8 × 109 tonnes (t) CO2, which is more than 100 times the current annual emissions of large point sources in the Songliao Basin.

Deep geological storage of carbon dioxide (CO2) could offer an essential solution to mitigate greenhouse gas emissions from the continued use of fossil fuels. Currently, CO2 capture is both costly and energy intensive; it represents about 60% of the cost of the total carbon capture and storage (CCS) chain which is causing a bottleneck in advancement of CCS in China. This paper proposes capturing CO2 from coal chemical plants where the CO2 is high purity and relatively cheap to collect, thus offering an early opportunity for industrial-scale full-chain CCS implementation. The total amount of high concentration CO2 that will be emitted (or is being emitted) by the coal chemical factories approved by the National Development and Reform Commission described in this paper is 42 million tonnes. If all eight projects could utilize CCS, it would be of great significance for mitigating greenhouse gas emissions in China. Basins which may provide storage sites for captured CO2 in North China are characterized by large sedimentary thicknesses and several sets of reservoir-caprock strata. Some oil fields are nearing depletion and a sub-set of these are potentially suitable for CO2 enhanced oil recovery (EOR) and CCS demonstration but all these still require detailed geological characterization. The short distance between the high concentration CO2 sources and potential storage sites should reduce transport costs and complications. The authors believe these high purity sources coupled with EOR or aquifer storage could offer China an opportunity to lead development in this globally beneficial CCS option

To meet the ambitious EC target of an 80% reduction in greenhouse gas emissions by 2050, CO2 Capture and Storage (CCS) needs to move rapidly towards full scale implementation with geological storage solutions both on and offshore. Onshore storage offers increased flexibility and reduced infrastructure and monitoring costs. Enabling onshore storage will support management of decarbonisation strategies at territory level while enhancing security of energy supply and local economic activities, and securing jobs across Europe. However, successful onshore storage also requires overcoming some unique technical and societal challenges. ENOS will provide crucial advances to help foster onshore CO2 storage across Europe through: 1. Developing, testing and demonstrating in the field, under “real-life conditions”, key technologies specifically adapted to onshore storage. 2. Contributing to the creation of a favourable environment for onshore storage across Europe. The ENOS site portfolio will provide a great opportunity for demonstration of technologies for safe and environmentally sound storage at relevant scale. Best practices will be developed using experience gained from the field experiments with the participation of local stakeholders and the lay public. This will produce improved integrated research outcomes and increase stakeholder understanding and confidence in CO2 storage. In this improved framework, ENOS will catalyse new onshore pilot and demonstration projects in new locations and geological settings across Europe, taking into account the site-specific and local socio-economic context. By developing technologies from TRL4/5 to TRL6 across the storage lifecycle, feeding the resultant knowledge and experience into training and education and cooperating at the pan-European and global level, ENOS will have a decisive impact on innovation and build the confidence needed for enabling onshore CO2 storage in Europe. ENOS is initiating strong international collaboration between European researchers and their counterparts from the USA, Canada, South Korea, Australia and South Africa for sharing experience worldwide based on real-life onshore pilots and field experiments. Fostering experience-sharing and research alignment between existing sites is key to maximise the investment made at individual sites and to support the efficient large scale deployment of CCS. ENOS is striving to promote collaboration between sites in the world through a programme of site twinning, focus groups centered around operative issues and the creation of a leakage simulation alliance.

The UK GeoEnergy Test Bed (GTB) is a field laboratory founded by the University of Nottingham and The British Geological Survey (BGS) for subsurface research into fluid migration through natural pathways. The GTB was initiated with funding from the founding partners and has received capital investment from the UK Government’s Treasury as part of the Energy Research Accelerator (ERA) project. The GTB will act as a research hub to catalyse scientific collaboration between researchers from academic and industrial backgrounds. The aim of the GTB is to advance geoscientific research to support the global need for secure, sustainable and safe energy. Geophysical, geochemical, petrochemical and hydrogeological data have been collected during site characterization and used to build a conceptual geological model. Permission is being sought from the relevant authorities to inject a small amount of food-grade CO2. Surface and downhole technologies and techniques will be used to monitor site behaviour before, during and after fluid injection. The sensing capability at the GTB has been designed by the BGS to enable interrogation of the subsurface in 4D and to a level of detail commensurate with energy processes in the subsurface.

The South-Africa Europe Cooperation in Carbon capture and Storage (SAfECCS) project was initiated in 2011. The aim of the project is to support the South African Centre for Carbon Capture and Storage (SACCCS) Roadmap for Carbon Capture and Storage (CCS) in South Africa through assessing the potential for geological storage, the impact of the existing legal framework and the relevance of possible funding streams for the proposed Test Injection Project as well as by undertaking capacity building and knowledge sharing activities.

This paper presents an overview of some recent CO 2 storage capacity assessments in the Songliao and Subei Basins in China, and a discussion of some of the specific challenges that must be addressed to further assess the feasibility of CO 2 storage in China. Geological CO 2 storage associated with CO 2 -EOR is of significant interest in these basins as it offers potential to increase oil production and provide additional fuel to meet China’s increasing energy consumption. Although some CO 2 is stored during such flooding projects, the greatest storage potential is only realised at the end of a field’s productive life, when a depleted field can be used as a dedicated CO 2 storage reservoir. The Songliao Basin, in North-eastern China has been the largest oil and gas producing province in China. The oilfields of the Daqing and Jilin oil provinces are estimated to have effective CO 2 storage capacities of 593 Mt and 71.2 Mt respectively. Extrapolation of data from around the oilfields to the whole basin suggests that the most promising saline aquifer in the basin has a theoretical storage capacity of 692 Mt CO 2 : Its effective storage capacity (which cannot be estimated due to lack of data) is likely to be considerably smaller however. Limited data availability means the estimate of storage capacity in this saline aquifer is based on gross simplifications and extrapolation across large areas (e.g. basin-scale) but could provide a basis for comparison with the potential for CO 2 storage in other regions in China, or to help prioritise more detailed analysis. Although smaller, the onshore oilfields of the Subei-Yellow Sea Basin were also assessed, as the presence of mature oil and gas fields and natural CO 2 accumulations, suggest suitable targets for storage may be found. The total effective storage capacity of the 108 hydrocarbon fields in this basin are estimated to be only 21 Mt CO 2 . While small, these fields may offer niche storage options for smaller industrial CO 2 sources, but if CCS is to contribute to reducing China’s growing CO 2 emissions, then further evaluation and development of storage in saline aquifers is likely to be needed at the same time as storage in oil or gas fields.

The storage potential of selected sites within the Bahaiwan Basin was evaluated, the storage capacity estimated and the selection criteria considered for the COACH project. This paper examines the two methods used during the project for calculation of the storage capacity in the Shengli oilfield complex within the Bahaiwan Basin. Both methodologies were used to quantify the potential CO 2 storage capacity of the depleted oil hydrocarbon reservoirs of the Shengli oilfield complex. They can both be considered as “simple” equation models which try to capture an “approximation” of a possible storage capacity. Nevertheless, between these models several differences exist. The CSLF methodology works with replacement of oil, gas or formation water, but does not incorporate dissolution of CO 2 in formation water. The EOR methodology of CUPB developed from methodology of Tanaka et al. on the other hand includes dissolution of CO 2 into the formation water, but does not consider the time period needed for the dissolution.

Geological assessment of the Bohaiwan Basin in eastern China for the COACH (Cooperation Action within CCS China-EU) project indicated that storing carbon dioxide (CO2) in this region will be technically challenging and require a flexible storage solution. It is suggested that a pilot scheme within the Dagang oil field complex could prove the concept of Carbon Capture and Storage (CCS) and CO2-Enhanced Oil Recovery (CO2-EOR) in the challenging conditions of oil fields in this region of China. This could be followed by simultaneous injection of CO2 into a nearby larger oil field and adjacent aquifers that would offer a potential storage option by combining the larger storage space anticipated for aquifers with the possible future financial incentives of CO2-EOR.

Synopsis Basin subsidence and thermal history models of the eastern part of the Midland Valley of Scotland have been constructed to characterize the development of the Midlothian-Leven synclinal basin from the mid Mississippian to the present day. Two modelling programs were used: BasinMod and HotPot. BasinMod models are based on thermal maturity at borehole sites; HotPot models operate on stacks of 2D layer grids using a mechanical compaction method. The thermal and burial history modelling indicates up to 1.9 km of additional burial of Carboniferous strata compared to present day levels: up to 660 m deposited by the end of the Carboniferous period, subsequently removed by Variscan uplift and erosion, followed by up to 1.9 km of burial by sedimentary rocks deposited during the Permian to the Palaeogene periods. Temperatures greater than 130 °C were reached by the most deeply buried Carboniferous sedimentary rocks. Mississippian (Lower Carboniferous) rocks reached the oil generation window during the mid Carboniferous, with Pennsylvanian (Upper Carboniferous) rocks reaching the oil generation window during the Cretaceous. Sedimentation rates were of 0.03–0.63 m ka −1 (metres per thousand years) with changes in the rate and the positions of depocentres consistent with both extensional and strike-slip basin formation.

The storage potential of selected sites within the Bohai Basin was assessed for the COACH project. The Gangdong oilfield is considered to have a small potential storage capacity (23 Mt) and to be possibly suitable for an enhanced oil recovery or small-scale storage pilot rather than large-scale storage. The Shengli oilfield province is considered to have a great potential storage capacity (472 Mt in eight selected fields), however, these fields, like those of the Gangdong oilfield province, are compartmentalised by faulting and stratigraphy and likely to be quite challenging for injection. Unmineable coal seams in the Kailuan mining area were also considered for storage, the estimated capacity is 504 Gt adsorbed onto the coal and 38,100 Mt void storage capacity. However, the coals have low porosity and permeability, so they would be expected to have poor injectivity. This is also an active mining area and so any storage site would have to be chosen carefully to avoid affecting future energy resources. The Huimin sub-basin within the Jiyang Depression was identified for consideration as an aquifer storage site; the Guantao Formation has good porosity and permeability in this region, and the regional-level storage capacity of these areas was estimated to be 0.7 Gt. The aquifers in the Huimin sub-basin appear promising for storage, however, less data are available than for the oilfields and the sealing formations are not directly proven to trap buoyant fluids, though in adjacent oilfield in the Shengli oilfield province, the Minghuazhen Formation forms a regional seal for the Guantao Formation.

The Cooperation Action Carbon Capture and Storage China-EU project (COACH) is a three-year EC Framework 6 co-funded collaborative project with Chinese and EU partners investigating geological storage options in the Bohai Basin, China. This paper discusses interim assessments of storage potential for the Dagang oilfield complex (Tianjin Municipality), deep saline aquifers in the Jiyang depression (Shandong province) and the Kailuan coalfield (Hebei Province). Source-sink matching options are also discussed using large ‘point source’ data collected for the Shandong Province.

Publisher Summary The CO2 storage potential of the U.K. sector of the Southern North Sea has been intensively studied in the EU Energie Programme project, European Potential for Geological Storage of Carbon Dioxide from Fossil Fuel Combustion (GESTCO). This project determines the cost and practicality of extending carbon dioxide storage technology, similar to that being demonstrated at the Sleipner West gas field to the major industrial plant of western Europe. An inventory of industrial point sources of carbon dioxide in Belgium, the Netherlands, Germany, Denmark, and the U.K. demonstrates that the Southern North Sea Basin is surrounded by a significant proportion of northern Europe's heavy industry including many fossil fuel fired power plants, steel works and oil refineries / petrochemical complexes. Thus, the reservoir rocks of the Southern North Sea are ideally sited to act as a repository for CO2, which would otherwise be emitted to the atmosphere by these plants.