Enhanced Oil Recovery (EOR) is the process by which hydrocarbons are extracted from a reservoir by means other than natural pressure gradients while unconventional hydrocarbons (UOG) are those extracted from very low porosity reservoirs such as shales and coals.
Increasing recovery is widely recognised as a major opportunity to increase reserves in many mature petroleum provinces. EOR activities include gas injection and chemical and thermal recovery methods while unconventional hydrocarbons are usually extracted from organic-rich shales (shale gas and oil) and coals (coal bed methane (CBM)).
The two themes are complementary as extraction from unconventional reservoirs often involves some type of EOR. EOR can involve natural fluids such as gas injection or WAG (water–alternating-gas) or chemical methods such as polymer flooding and low salinity waterflooding.
The key technical challenges in these areas are to develop a fuller understanding of the basic physics and chemistry of these complex EOR and UOG processes in order that that a more reliable predictive models of these processes can be constructed.
It is important that the best and most conscientious researchers take on these projects due to the sensitive nature of the subject. A multi-disciplinary and integrated approach is also vital with a team including geoscientists, engineers, chemists, and mathematical modellers along with the later involvement of economists, policy analysts and government and public bodies.