Page 107 - Primer on Enhanced Oil Recovery

Gas flooding 97

Figure 10.2 EOR Production of thermal recovery and gas flooding in USA.

1980 1986, when the number of implemented projects increased due to an increase
in the oil price. During this time, the number of projects increased from 35 to 105,
and the oil production increased to 108.2 thousand barrels per day.
The second period began in 2002, also due to a significant increase in the price
of oil. During this period, the number of projects increased from 76 (2002) to 156
(2014), and production from 297.5 to 471 thousand barrels per day. At the same
time, in 2006, for the first time, oil production by the implementation of gas meth-
ods exceeded the oil production obtained by the use of thermal methods (see
Fig. 10.2).

10.1 CO injection
2
The use of carbon dioxide flooding to increase oil recovery started in 1950 and has
been very successful. This success is firmly based on many laboratory studies, field
trials and the application experiences.

10.1.1 Background processes
In order to understand why carbon dioxide became an important working agent for
injection into oil reservoirs, we must reflect first on the gas main properties and fac-
tors that make CO 2 a useful tool for the enhanced oil recovery.
Carbon dioxide is a colorless, odorless, inert and non-combustible gas. It has a
molecular weight of 44.01. This is one and a half times higher than molecular