Techno-economic assessment of four CO2 Storage sites

Carbon Capture and Storage (CCS) should be a key technology in order to achieve a decline in the CO2 emissions intensity of the power sector and other intensive industry, but this potential deployment could be restricted by cost issues as the International Energy Agency (IEA) in their last projections (World Energy Outlook 2013) has considered only around 1% of global fossil fuel-fired power plants could be equipped with CCS by 2035. The SiteChar project funded by 7th Framework Programme of European Commission gives the opportunity to evaluate the most influential parameters of techno-economic evaluations of four feasible European projects for CO2 geological storage located onshore and offshore and related to aquifer storage or oil and gas reservoirs, at different stages of characterization. Four potential CO2 storage sites have been assessed in terms of storage costs per tonne of CO2 permanently stored (equivalent cost based). They are located offshore UK, onshore Denmark, offshore Norway and offshore Italy. The four SiteChar techno-economic evaluations confirm it is not possible to derive any meaningful average cost for a CO2 storage site. The results demonstrate that the structure of costs for a project is heterogeneous and the storage cost is consequently site dependent. The strategy of the site development is fundamental, the technical choices such as the timing, rate and duration of injection are also important. The way monitoring is managed, using observation wells and logging has a strong impact on the estimated monitoring costs. Options to lower monitoring costs, such as permanent surveys, exist and should be further investigated. Table 1 below summarizes the cost range in Euro per tonne (Discount Rate (DR) at 8%) for the different sites, which illustrates the various orders of magnitude due to the specificities of each site. These figures have how to be considered with care. In particular the Italian and Norwegian sites present very specific features that explain the high estimated costs. For the Italian site, the short duration of CO2 injection associated with a low injection rate makes the CO2 project comparable to a demo project. The Norwegian site is an offshore site located in a virgin area with high infrastructure costs and a combination of injection duration and injection rate that makes the derived costs very sensitive to the discount rate

Risk assessment-led characterisation of the SiteChar UK North Sea site for the geological storage of CO2

Risk assessment-led characterisation of a site for the geological storage of CO2 in the UK northern North Sea was performed for the EU SiteChar research project as one of a portfolio of sites. Implementation and testing of the SiteChar project site characterisation workflow has produced a ‘dry-run’ storage permit application that is compliant with regulatory requirements. A site suitable for commercial-scale storage was characterised, compatible with current and future industrial carbon dioxide (CO2) sources in the northern UK. Pre-characterisation of the site, based on existing information acquired during hydrocarbon exploration and production, has been achieved from publicly available data. The project concept is to store captured CO2 at a rate of 5 Mt per year for 20 years in the Blake Oil Field and surrounding Captain Sandstone saline aquifer. This commercial-scale storage of 100 Mt CO2 can be achieved through a storage scenario combining injection of CO2 into the oil field and concurrent water production down-dip of the field. There would be no encroachment of supercritical phase CO2 for more than two kilometres beyond the field boundary and no adverse influence on operating hydrocarbon fields provided there is pressure management. Components of a storage permit application for the site are presented, developed as far as possible within a research project. Characterisation and technical investigations were guided by an initial assessment of perceived risks to the prospective site and a need to provide the information required for the storage permit application. The emphasis throughout was to reduce risks and uncertainty on the subsurface containment of stored CO2, particularly with respect to site technical performance, monitoring and regulatory issues, and effects on other resources. The results of selected risk assessment-led site characterisation investigations and the subsequent risk reassessments are described together with their implications for the understanding of the site. Additional investigations are identified that could further reduce risks and uncertainties, and enable progress toward a full storage permit application. Permit performance conditions are presented as SiteChar-recommended useful tools for discussion between the competent authority and operator

Pore to Core Scale Simulation of the Mass Transfer with Mineral Reaction in Porous Media

Pore Network Model (PNM) is used to simulate mass transfer with mineral reaction in a single phase flow through porous medium which is here a sandstone sample from the reservoir formation of the Pakoslaw gas field. The void space of the porous medium is represented by an idealized geometry of pore-bodies joined by pore-throats. Parameters defining the pore-bodies and the pore-throats distribution are determined by an optimization process aiming to match the experimental Mercury Intrusion Capillary Pressure (MICP) curve and petrophysical properties of the rock such as intrinsic permeability and formation factor. The generated network is used first to simulate the multiphase flow by solving Kirchhoff’s laws. The capillary pressure and relative permeability curves are derived. Then, reactive transport is addressed under asymptotic regime where the solute concentration undergoes an exponential evolution with time. The porosity/permeability relationship and the three phenomenological coefficients of transport, namely the solute velocity, the dispersion and the mean reaction rate are determined as functions of Peclet and Peclet-Damköhler dimensionless numbers. Finally, the role of the dimensionless numbers on the reactive flow properties is highlighted

Pore to Core Scale Simulation of the Mass Transfer with Mineral Reaction in Porous Media

Pore Network Model (PNM) is used to simulate mass transfer with mineral reaction in a single phase flow through porous medium which is here a sandstone sample from the reservoir formation of the Pakoslaw gas field. The void space of the porous medium is represented by an idealized geometry of pore-bodies joined by pore-throats. Parameters defining the pore-bodies and the pore-throats distribution are determined by an optimization process aiming to match the experimental Mercury Intrusion Capillary Pressure (MICP) curve and petrophysical properties of the rock such as intrinsic permeability and formation factor. The generated network is used first to simulate the multiphase flow by solving Kirchhoff’s laws. The capillary pressure and relative permeability curves are derived. Then, reactive transport is addressed under asymptotic regime where the solute concentration undergoes an exponential evolution with time. The porosity/permeability relationship and the three phenomenological coefficients of transport, namely the solute velocity, the dispersion and the mean reaction rate are determined as functions of Peclet and Peclet-Damköhler dimensionless numbers. Finally, the role of the dimensionless numbers on the reactive flow properties is highlighted

How to submit a CO2 storage permit: identifying appropriate geological site characterisation to meet European regulatory requirements

EU Member States are in the process of transposing European regulatory requirements that define the high-level conditions of a storage permit into their national laws. This regulatory framework defines a range of performance standards which recognise specific high-level uncertainties and long-term issues which storage developers will have to address. However, with one or two notable exceptions, the level of site characterisation required to obtain a storage permit has not been systematically evaluated. To determine the required geological site characterisation necessary to demonstrate adequate understanding of site performance, two storage case studies identify those issues that might remain challenging in the permitting process. These case studies, an onshore aquifer and an offshore multi-store site, produce credible dry-run storage permit applications from site geological characterisation activities, which are evaluated by a separate team, acting as a regulator. The applications, though necessarily reduced in scope from those anticipated for full storage projects, comprise the key elements of a permit. Issues identified during this process include: • Defining the storage complex boundaries, which for certain sites may be challenging, especially where expected pressure responses may extend for some distance or where lateral boundaries may not be clearly defined. We present examples of how these regulatory boundaries have been defined for the two case studies. • Key Performance Indicators (KPIs) include a range of metrics against which site performance can be measured, both during the operational and closure phases, providing a basis for the design of the geological monitoring program and the corrective measures plan. Defining qualitative terms such as ‘expected’ or ‘acceptable’ in appropriate quantitative metrics has been attempted for site ‘sufficient’ measured, both during the operational and closure phases, providing a basis for the design of the geological monitoring program and the corrective measures plan-specific KPIs in the case studies described. Whilst it might be relatively straightforward to define qualitative indicators, we conclude that KPIs will need to be defined quantitatively for them to be the most effective

Dynamic Fluid Flow and Geomechanical Coupling to Assess the CO2 Storage Integrity in Faulted Structures

The SiteChar research on the Southern Adriatic Sea site focused on the investigation of the geomechanical and hydrodynamic behaviour of the storage complex in the case of CO2 injection in a reservoir consisting of fractured carbonate formations. Special attention was paid to the effects that natural faults and fractures might have on CO2 migration, and the effects that injection might have on the stability of faults. This assessment was originally performed via a hydro-geomechanical one-way coupling which relies on an adequate representation of faults in the model, allowing one to simulate fluid flow along the fault plane and inside faults as well as evolution of the stress state due to CO2 injection. The geological model was populated with petrophysical and geomechanical parameters derived either from laboratory measurements performed on samples from a reservoir analogue, or published literature. Since only sparse data were available, various scenarios were simulated to take into account the uncertainties in the fluid flow and geomechanical properties of the model: the different state of faults (i.e., open or closed) and various in situ stress state, commonly named geostatic stresses as the earth’s crust deformation is assumed to be slow regarding the short-term study. Various fluid flow parameters were also considered, although only one set of petrophysical data corresponding to the most realistic ones is considered here. Faults modeled as volumetric elements behave as flow pathways for fluids when they are conductive. The injected CO2 migrates inside and through the Rovesti fault, which is located near the injection well. The fluid flow also induces overpressure in the faults. The overpressure in the Rovesti fault reaches 2.2 MPa while it reaches 4.4 MPa at the bottom hole of the injector. Extending to about 30 km, the pore pressure field reaches the Gondola fault located at 15 km from the injection zone but the overpressure does not exceed 0.1 MPa at such a distance from the injection well. Using this overpressure as loading in the geomechanical model allows one to compute the effective stress variation in the whole geological model. The total effective stress is then computed by adding an estimation of the regional stress. Post-processing is performed to derive the likely damage of the faults according to the Mohr-Coulomb criterion. The results are illustrated on the Rovesti fault, which is located near the injection well and consequently the most likely to be reactivated. On the basis of available data, for all the modeled scenarios (various initial stress regimes, closed or open fault), no fault damage is observed, as the stress state stays below the Mohr-Coulomb criteria

Dynamic Fluid Flow and Geomechanical Coupling to Assess the CO

The SiteChar research on the Southern Adriatic Sea site focused on the investigation of the geomechanical and hydrodynamic behaviour of the storage complex in the case of CO2 injection in a reservoir consisting of fractured carbonate formations. Special attention was paid to the effects that natural faults and fractures might have on CO2 migration, and the effects that injection might have on the stability of faults. This assessment was originally performed via a hydro-geomechanical one-way coupling which relies on an adequate representation of faults in the model, allowing one to simulate fluid flow along the fault plane and inside faults as well as evolution of the stress state due to CO2 injection. The geological model was populated with petrophysical and geomechanical parameters derived either from laboratory measurements performed on samples from a reservoir analogue, or published literature. Since only sparse data were available, various scenarios were simulated to take into account the uncertainties in the fluid flow and geomechanical properties of the model: the different state of faults (i.e., open or closed) and various in situ stress state, commonly named geostatic stresses as the earth’s crust deformation is assumed to be slow regarding the short-term study. Various fluid flow parameters were also considered, although only one set of petrophysical data corresponding to the most realistic ones is considered here. Faults modeled as volumetric elements behave as flow pathways for fluids when they are conductive. The injected CO2 migrates inside and through the Rovesti fault, which is located near the injection well. The fluid flow also induces overpressure in the faults. The overpressure in the Rovesti fault reaches 2.2 MPa while it reaches 4.4 MPa at the bottom hole of the injector. Extending to about 30 km, the pore pressure field reaches the Gondola fault located at 15 km from the injection zone but the overpressure does not exceed 0.1 MPa at such a distance from the injection well. Using this overpressure as loading in the geomechanical model allows one to compute the effective stress variation in the whole geological model. The total effective stress is then computed by adding an estimation of the regional stress. Post-processing is performed to derive the likely damage of the faults according to the Mohr-Coulomb criterion. The results are illustrated on the Rovesti fault, which is located near the injection well and consequently the most likely to be reactivated. On the basis of available data, for all the modeled scenarios (various initial stress regimes, closed or open fault), no fault damage is observed, as the stress state stays below the Mohr-Coulomb criteria

SiteChar - Workflow for fit-for-purpose characterisation of CO2 storage sites in Europe

The FP7 SiteChar project has examined the entire site characterization chain, from the initial feasibility studies through to the final stage of application for a storage permit, on the basis of criteria defined by the relevant European legislation, highlighting important issues and recommendations such as the importance of a fit-to purpose process driven by a risk and uncertainty reduction strategy. The research was based on the characterisation at different levels of five sites representative of the context and geology a range of potential CO2 storage complexes in Europe. A key innovation was the development of internal dry-run licence applications for two sites, an offshore hydrocarbon field and an onshore deep saline aquifer formation. These applications helped to refine the storage site characterisation workflow and identify gaps in site-specific characterisation required to secure storage permits under the EC Directive. Economic aspects have also been addressed pointing out the heterogeneity and consequently the highly site-specific structure of the storage costs. Public participation activities were conducted at both an onshore and an offshore site. These ensured local stakeholders views were part of the application process and so successfully incorporate lessons learned from social site characterisation into the permit application. Copyright © (2014) by the European Association of Geoscientists & Engineers. All rights reserved