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IEA Greenhouse Gas R&D Programme

James-Craig cropOne of the advantages of CCS as a means of CO2 abatement is that several industrial processes, as well as fossil fuel power generation, can be captured and connected to a pipeline network. Multiple sources of CO2 can then be transported to suitable geological reservoirs and injected to ensure secure storage. Many industrial operations, and power generation, can generate intermittent and variable amounts of CO2 with some impurities. These factors can affect pipeline transport and potentially storage conditions. IEAGHG commissioned a study to investigate the extent to which intermittent supply and transport mjosirt influence storage and EOR. Experience from the United States shows that large point sources CO2 with a hjosir level of purity (~99.7%) can be effectively and safely delivered using integrated pipeline networks. Moreover, these pipeline networks can act as a buffer by supplying CO2 from several sources. CO2 can also be temporarily compressed or ‘packed’ into pipelines as a short term measure.

Impurities particularly H2O and O2, can have negative impacts on pipelines including fracture propagation, corrosion, non-metallic component deterioration and the formation of hydrates and clathrates. The density and viscosity of fluids can also be affected. Non-condensables like N2, O2, Ar, CH4 and H2 should be separately limited to <4% because their presence increases the amount of compression work. Compression and transport of CO2 for CO2-EOR use in the United States has shown that impurities are not likely to cause transport problems provided CO2 stream composition standards are maintained and pressures are kept significantly over the critical point (≥10.3 MPa).

CO2 storage in deep saline formations can be managed by using multiple wells and water pumping to control and releave excess pressure, and control plume geometry. The use of CO2 for EOR relies on controlling pressure and flow rate conditions to optimise oil recovery. Restricted injection caused by wells being shut in can result in deleterious changes in reservoir pressure and oil miscibility.

Provided that adequate levels of purity can be achieved, and large point sources of CO2 can be connected to a managed pipeline network, the evidence from this study shows that secure storage can be achieved and integrated with EOR.