Introduction to Geological Sequestration - Introduction to Carbon Capture and Sequestration - page 366

Figure 8.3.3 Pipelines in the USA for transporting CO 2 for enhanced oil recovery
Figure based on information from [8.4].
focused for many years on ensuring that as little CO 2 as possible is used,
because producing and transporting CO 2 is expensive. The importance
of enhanced oil recovery is that it demonstrates that we have the technol-
ogy to transport CO 2 over large distances and inject it into geological
formations [8.4]. Of course, in the context of CCS one would like to maxi-
mize CO 2 utilization! But even if one could maximize the amount of CO 2
“lost” in the reservoir, the total use of CO 2 for enhanced oil recovery
would still be a small fraction of the total amount of CO 2 we would like to
sequester in the context of CCS. CO 2 can also be used to enhance the
production of natural gas. In this application CO 2 is used to re-pressurize
the gas fi elds.
Deep saline aquifers
An aquifer is defi ned as a formation of permeable rocks saturated with
water, with a degree of permeability that allows water withdrawal through
wells. If an aquifer allows water withdrawal, then it will also allow injection
of fl uids. At present those deep aquifers not considered usable for drink-
ing water are already used for disposal of waste water, disposal of acid