2012
Deliverable summary
Deliverable 3.2 Summary
Maxine Akhurst
D3.2 Storage design, UK site
The storage design of the UK North Sea site is presented from the results of flow simulations of CO2 injection, prediction of regional migration flow paths and analysis of well integrity. Scenarios for storage are calculated to test components of the multi-store site by injection into the depleted hydrocarbon field and injection and fluid production in the host Captain Sandstone. Annual CO2 injection rates of 5 Mt for 20 years (dynamic storage capacity of 100 Mt) followed by 30 years relaxation indicate that to avoid excessive reservoir pressures it is essential to inject into the hydrocarbon field and more fully understand sandstone heterogeneity, properties of the hydrocarbon and permeability of the fluids. Coupling CO2 injection with fluid production predicts pressures of less than 30 bar over the initial value. By substantially over-filling the storage site potential pathways for CO2 migration beyond the storage site are mapped. The most probable pathway to the surface of the stored CO2 is via leaking wells and not indirectly via pathways originating in deeper parts of the overburden. Permeability of cement bond is the parameter that most effects CO2 flow through an abandoned well. Additional characterisation of cement bond, permeability and cement thickness is recommended.