Environmental Engineering Reference
In-Depth Information
Depleted oil and gas reservoirs
The fact that natural gas has been trapped in these reservoirs for millions
of years suggests that they can trap buoyant CO 2 . In addition, data col-
lected from wells and seismic surveys usually provide excellent knowl-
edge about these sites. A disadvantage of these sites is that, because of
the gas and oil production, wells have been drilled in the caprock, so one
would need to be absolutely sure that these old wells are adequately
plugged.
Enhanced oil and gas recovery
Under certain conditions, CO 2 can dissolve in oil, reducing its viscosity
and density and thereby increasing its mobility through the pore space.
This phenomenon has been used in the oil industry for many years to
increase the fraction of oil recovered from an oil fi eld, a process known
as CO 2 -enhanced oil recovery (CO 2 -EOR) (see Figure 8.3.2 ). In fact,
Figure 8.3.3 shows some of the pipelines that have been built in the USA
to transport CO 2 from natural reservoirs to oil fi elds for the purpose of
enhanced oil recovery. Interestingly, EOR research in the oil industry has
Figure 8.3.2 Enhanced Oil Recovery
The idea of enhanced oil recovery is that by injection of CO 2 we can reduce the viscosity
and density of the oil; because of this, a greater fraction of the oil can be recovered.
Picture from CO2CRC. Copyright by CO2CRC, reproduced with permission [8.2].
Search WWH ::




Custom Search