State of the art review of CO2 Storage Site Selection and Characterisation Methods

 
1. INTRODUCTION
 
2. GEOLOGICAL CHARACTERISATION OF THE SITE
 
3. FLOW MODELLING
 
4 REACTIVE FLOW MODELLING
 
5. COUPLED GEOMECHANICAL AND FLOW MODELLING
 
6. ENVIRONMENTAL IMPACT AND RISK ASSESSMENT
 
7. ECONOMIC ANALYSIS
 
8. PUBLIC PERCEPTION AND ACCEPTANCE
 
9. CONCLUSIONS AND RECOMMENDATIONS
 
 
2.1 Site screening criteria
 
2.2 Storage capacity estimation methods
 
2.3 Safety of CO2 storage in saline aquifers
 
2.4 CO2 storage site ranking criteria
 
2.5 Conclusions
 
 
» 2.4.1 Site ranking criteria for saline aquifers
 
2.4.2 Ranking criteria for hydrocarbon fields and coal beds
 
 

2.4.1 Site ranking criteria for saline aquifers

Site ranking is in principle based on results of screening and storage capacity estimations, which make a preliminary characterisation and storage safety assessment, together with the analysis of potential conflicts of use. First, Tab. 2-1 presented earlier should be completed for every site considered and existing knowledge gaps identified. However, this assessment only considers the results of the preliminary screening. In the CO2QUALSTORE project (Aarnes, 2010), an approach based on risk identification evaluating the above mentioned outcomes has been used (Tab. 2-9). Although the approach is universal, saline Aquifers are considered more sensitively than depleted/depleting hydrocarbon fields and un-mineable coal beds.

Tab. 2-9: Screening and Ranking of storage sites after the CO2QUALSTORE project (Aarnes, 2010).

Screening activities

Deliverables

Define screening basis

Initiate the phase and develop criteria for nominating one or more sites for further assessment

List of criteria that a site should meet to be eligible for further site assessment

Develop screening plan

Describe screening actions required for fulfilling the criteria defined in screening basis step

Screening plan

Review available data and identify potential sites

Review available data and identify potential sites

List of potential storage sites

Estimate capacity and level of uncertainty

Prepare capacity estimates and estimates of uncertainty of input and output parameters

Capacity estimates with quantified uncertainties for potential storage sites

Identification and assessment of risks and uncertainties

Develop initial register of risks and uncertainties

Initial risk register

Select site(s) for further assessment

Decide which sites, if any, should be assessed further

Screening report and final selection of site(s) nominated for further assessment

M2: Shortlist storage sites

Main question: Is there an adequate level certainty that further site assessment will provide confidence that at least one of the nominated storage sites is suitable for long term geologic storage of the intended volumes of CO2?

Decision: Commit budget and resources for the assessment stage.

In particular, the following risks have to be addressed from this viewpoint:

  • legal and regulatory (is it possible to obtain storage permit; document the screening results; avoid conflicts of use of the subsurface for other resources - e.g. hydrocarbons, geothermal, gas/waste storage, etc.; locate storage and transport infrastructure as planned - no conflicts with land use);
  • geological and environmental (reservoirs, tectonics, hydrogeology and natural hazards evaluated; reservoir and caprock properties known sufficiently together with aquifers and caprocks within overburden where CO2 could leak; storage capacity and injectivity known sufficiently; existing wells identified as possible leakage paths; possible impact to vulnerable natural resources identified - potable aquifers, nature protected areas).

For example, the presence of areas of protected wildlife and nature (Fig. 2-11) onshore, within coastal areas and in some areas further offshore would make it impossible to develop injection infrastructure in some areas (the authority would likely not risk granting a storage permit) and difficult to develop transport infrastructure.

Often, existing knowledge gaps and uncertainties might be so significant that drilling new Wells and carrying out new seismic and other geophysical surveys is necessary to evaluate and rank preliminary identified sites (as in the case of the Bełchatów demo project Fig. 2-9). Then the whole procedure listed in Tab. 2-1 has to be repeated and further steps taken, as indicated in Fig. 2-12 (Aarnes, 2010).

E. Fig . 2-11

Fig. 2-11 - NATURA 2000 protected areas in the EU (European Environment Agency).

E. Fig . 2-12

Fig. 2-12: Site ranking and selection procedure after the CO2QUALSTORE project (Aarnes, 2010).