Already during the application of a storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere project it is necessary to provide evidence that at the selected project site CO2Carbon dioxide storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere can be performed safely. Therefore a site-characterization is necessary. The characterization of the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids and the site is an iterative process, which consists of the following major elements:
- Data acquisition, monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions;
- Geological model;
- Dynamic modelling;
- Risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system.
The geological model is based on the acquired data. The main parameters of the geological model are the model area, the geometry, grid size, possible migrationThe movement of fluids in reservoir rocks pathways within the model area, faults and other tectonic attributes. Due to constant monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions of the site more data becomes available so the geological model can be adapted and reaches more realistic values.
The static geological model is then used to perform dynamic models in order to predict the behaviour of the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids once CO2Carbon dioxide is injected. The dynamic model uses a flow model (based on the geometry characteristics of the geological model) to estimate the size of the plume, possible trapping(CO2) Containment or immobilisation of CO2, there are four main trapping mechanisms: structural or stratigraphic trapping; residual CO2 trapping (capillary trapping) by capillary forces; solubility trapping by dissolution of CO2 in resident formation fluids forming a non-buoyant fluid; and mineral trapping where CO2 is absorbed by solid minerals present in the storage volume mechanisms and the displacement of any other fluids present in the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids. It will further use coupled models to take into account geochemical and geo-mechanical changes in the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it, like pressure and stress. The results of different short-/long-term scenarios of the dynamic models are then compared to identify the site-specific uncertainties.
There is always an interaction between the 3 main players, geological model - dynamic model - risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system.
In general risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system is most effective prior to or at early stages of injectionThe process of using pressure to force fluids down wells because the risks decrease with time after cessation of injectionThe process of using pressure to force fluids down wells. This is not always true due to geochemical effects that may be slow and therefore will reach high riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event at some point during post-closurePeriod after transfer of responsibility to the competent authority or due to slow migrationThe movement of fluids in reservoir rocks of the plume which may lead the plume into the vicinity of a leaky wells or open faults. Also tectonic activity could cause breaching of physical traps, which is dangerous if CO2Carbon dioxide is still in a mobile stage. So geochemistry and migrationThe movement of fluids in reservoir rocks should be a part in any long-term stability evaluation for risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system.
If the monitored CO2 plumeDispersing volume of CO2-rich phase contained in target formation is not behaving like in the predicted model the used geological and dynamical model require adjustments. The comparison stops as soon as a confident model is developed which agrees with the monitored data. Risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system in general is based on the geological settings and should basically answer the following considerations: How likely is leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column? How likely is leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column due to faults, wells and fractures of the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids? What size of leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column (leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column rate) is possible? Is there potential geo-mechanical failure, and if yes what kind? Which are the critical parameters for this site? Where to best install monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions? Is there an environmental impact on the surrounding area? Are there any negative influences on population living in the vicinity?
International regulations
The "OSPARConvention for the Protection of the Marine Environment of the North-East Atlantic, which was adopted at Paris on 22 September 1992 FRAM" guidelines for risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system for CO2Carbon dioxide storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere in the marine environment are very prescriptive and serve as model for performing risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system. The "Report on the international regulatory requirements" (Korre, 20112011 - A. KorreCO2CARE D1.1 International regulatory requirements on CO2 geological storage and site abandonmentsee more) states that: "Decision 2007/2 of the OSPARConvention for the Protection of the Marine Environment of the North-East Atlantic, which was adopted at Paris on 22 September 1992 parties requires use of the FRAM when issuing storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere permits". Also the London ProtocolProtocol to the London Convention, adopted in London on 2 November 1996 but which had not entered into force at the time of writing is accompanied by specific guidelines requiring use of OSPARConvention for the Protection of the Marine Environment of the North-East Atlantic, which was adopted at Paris on 22 September 1992 FRAM and especially many elements for assessing risks like migrationThe movement of fluids in reservoir rocks, leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column pathways and potential effects on the marine environment.
The OSPARConvention for the Protection of the Marine Environment of the North-East Atlantic, which was adopted at Paris on 22 September 1992 FRAM is based on six stages reaching from problem formulation and storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere-site characterization via the assessment of the site response when exposed to CO2Carbon dioxide injectionThe process of using pressure to force fluids down wells to riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event characterization and management, including monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions and remediation measures.
The IEAInternational Energy Agency model framework uses OSPARConvention for the Protection of the Marine Environment of the North-East Atlantic, which was adopted at Paris on 22 September 1992 FRAM as a basis for their regulations as wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids.
European regulations
Modelling guidelines in the EU CCS DirectiveDirective 2009/31/EC of the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide 2009/31/ECEuropean Commission are only prescriptive in respect to the required outcomes .No particular tool is mentioned for modelling and there are no details on the level of accuracy. These guidelines are the optimum for a regulatory situation. They prescribe standards but they leave room for updated technology and practice. Risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system regulations in the European Union are based on OSPARConvention for the Protection of the Marine Environment of the North-East Atlantic, which was adopted at Paris on 22 September 1992 FRAM.
USA regulations
UIC regulations state that no effect on underground sources of drinking water shall occur. Furthermore they require computational modelling with respect to the extent of the plume and formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it fluid (taking into account all properties of all phases of CO2Carbon dioxide) and any migrationThe movement of fluids in reservoir rocks through faults, fractures and artificial penetrations. They require extra detailed computational multiphase flow modelling, accountingActivities aiming to document and report avoided CO2 emissions for a project for geological heterogeneities and risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system for leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column. All the modelling should be updated periodically or whenever irregularities occur.
The World Resources Institute (WRI) provides guidelines on what risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system should achieve and lists assessment points. The main concerns are leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column, the fluids potential impact on confining zones and any possible endangerment to humans and environment. WRI asks for risk assessmentA process intended to calculate or estimate the risk to a given target, part of a risk management system to identify monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions requirements and provide the basis for mitigationThe process of reducing the impact of any failure. The guidelines require periodic updating and are site-specific.