Introduction

This guide provides information on where to find the material required to undertake initial national scale storage assessments. It is designed to help government bodies and policy makers with limited prior carbon capture and storage (CCS) experience find information regarding the methodology of conducting an assessment. A nationwide storage estimate is fundamental to progress CCS as a climate mitigation technology as it will determine how suitable the regional geology is for CO2 storage and provide an initial indication of capacity.

This guidance document includes definitions of technical terminology, proposed steps to establishing a national storage assessment and recent up to date case studies from a variety of countries focussing on Africa and Asia. A variety of methods for capacity estimation have been used and this report provides explanations of where to find these studies and sources of information including websites, papers and organisations. Most companies and organisations engaged in CCS development have stated their ambition to share knowledge and experience; and they actively collaborate at an international level to aid future projects. This guide provides a link with current expertise in CO2 storage to help facilitate new CCS projects especially in developing countries.

Many detailed storage assessments have been conducted and published in the past decade. A wide variety of techniques and technologies have been used to complete them given the varying nature of each country and individual sites. Although a standardised method has yet to be established, this guide aims to provide links to the most developed methodologies providing a direction on the most suitable approach to adopt.

At the conclusion of this guide there is a nine point summary of the key stages that are recommended for the establishment of a national CO2 storage assessment (see Section 7).

Key Stages for setting up a National CO2 Storage Assessment

The joint UK / South Korean funded survey clearly shows that building a national CO2 storage assessment should be compiled in a series of incremental steps:

• Develop a national strategy to produce a CO2 storage capacity estimate.  The strategy should first review whether there are existing national institutions that are capable of conducting an assessment.
   
• Appointment of a designated organisation, probably the national geological survey, to co-ordinate and collate key data on a country’s geology and geotechnical background.
   
• Set up a dedicated database that acts as a national repository for all key data that can be used to identify and characterise CO2 storage sites.
   
• Categorise data sets according to the level of confidence that can be accrued to the quality of data and reliance that can be placed on it.
   
• Depending on the level of data categorise a national CO2 storage resource based on an accepted terminology and scale, for example, basin-wide or regional-scale.
   
• Target specific formations such as DSFs that have some evidence of pressure / temperature, depth and structural characteristics that are suitable for CO2 storage.
   
• Initial capacity estimates can be volumetric, bearing in mind these can only provide a general indication of capacity.
   
• Apply dynamic estimates based on modelled projections of capacity that take account of pressure effects and numbers of wells.
   
• Dynamic estimates can be further refined, depending on the quantity and quality of data available.  Features such as the presence of faults, facies variations and other forms of geological heterogeneity are known to affect CO2 storage especially migration rates and distribution and therefore capacity.