Storage in Depleted Gas Fields

Publication Overview

The initial specification required a desk-based study to: 1. Assess the future implications for CO₂ storage of future natural gas production trends, especially the potential future exploitation of fields with naturally-high CO₂ 2. Undertake a source-sink matching exercise, utilising the IEA GHG database on point source emissions and with due consideration to existing transport pipeline infrastructure. The specification specifically stated that ship transportation should not be considered; content; 3. Determine the potential role of enhanced gas recovery (CO₂-EGR) in CO₂ 4. Develop an analytical screening process/tool for the selection of gas fields suitable for CO storage; 2 storage, allowing ranking of opportunities and assessment of potential global CO₂ 5. Estimate CO storage capacity; 2 6. Provide a summary of opportunities around the world where CO storage costs in depleted gas fields; 2 storage in depleted gas fields could be feasible from both technological and economic perspectives

Publication Summary

• Estimates of storage capacity derived from the study would be placed in the context of a resource classification scheme. The Carbon Sequestration Leadership Forum (CSLF) resource ‘pyramid’ (Figure 1) was chosen as the example to be used, although this was not to be reported as an endorsement above other similar classification schemes;
• The study would undertake only a brief review of issues concerning natural gas fields with high CO₂ content and CO₂-EGR (items 1 and 3 on the original scope), since the report authors considered these issues to have limited significance for the overall CO₂
• Re-use of existing pipelines would not be considered for the source-sink matching and costing elements of the study, since the suitability of such infrastructure would vary according to local factors; global storage potential of gas fields; therefore project resources would be better deployed on storage capacity estimation and cost analysis;
• Similarly, site-specific geological factors such as caprock and well integrity issues would not be described or directly assessed in the study;
• Due to the importance of localised factors as described above in assessing the suitability for CO₂ storage of any given gas field, the study would not seek to produce a screening tool for the ranking of gas field prospects (item 4 in the original scope). However a tool to enable regional source-sink matching with respect to time, based on the use of a geographic information system (GIS) would be developed.