**2. Current situation of CO2: EOR**

Enhanced oil recovery is done by the use of CO2 (CO2–EOR). It is a kind of CCUS technology. This practical application was started and improved as early as 1972, directing to improve oil recovery through the introduction of CO2 into oil reservoirs. (**Figure 1**) [2].

The current and active projects, where CO2–EOR is applied, have been developed mostly in the United States (Permian Basin, Gulf Coast, and the Rockies (see **Figure 1**.)), and in Canada in better proportion with seven projects of injection of CO2, plus another additional injection of acid gases; however, it is relevant to indicate that this method has also been practiced for several decades in Turkey and Hungary, and there are new projects in various stages of development in Asia, the Middle East, and the North Sea. On a pilot scale, there are also developments in China, Brazil (onshore – Miranga field), and Abu Dhabi.

As a consequence of the advantages of this method, as part of the KAPSARC data source, in 2020, there are 38 CO2–EOR large-scale projects in different project life cycle stages [3], and according to International Energy Agency (IEA), the entire amount of CCUS programs in industry and fuel transformation increase to 19 in 2020 when the two Alberta Carbon Trunk Line programs in Canada started activity (**Figure 2**) [2].

According to the information updated in 2020, it was identified that there was a decrease in the U.S. of approximately 47% of CO2 supplied for EOR projects compared

**Figure 1.** *Number of EOR projects in operation globally [2].* *Carbon Capture, Use and Storage (CCUS) as Enhanced Oil Recovery (EOR): Llanos Orientales… DOI: http://dx.doi.org/10.5772/intechopen.105949*

#### **Figure 2.**

*Sizeable CO2–EOR projects in different stages by applied industries [5].*

to that supplied in 2019, with one of the possible causes being the decline in oil and gas prices. However, the increment in prices in 2021 may lead to an increase in oil production through EOR–CO2 projects [4].

**Figure 2** indicates that the Century CO2–EOR plant in Texas is one of the projects with the most capacity per year. It was started in 2010 with a reduced capture capacity, but the volume was increased to its full capacity of 8.4 Mt./year in 2012 [5].

Also, the Shute Creek Gas processing installation in Wyoming, USA, has been handling natural gas from the LaBarge field beginning in 1986. Before improving it, H2S was separated along with approximately 0.4 Mt./a of CO2. In 2010, an expansion of the plant's capacity was finished, getting a capture capacity of 7 Mt./a of CO2 [5].

Another project is the Val Verde Natural Gas Facility in Texas, USA. Currently, five different gas processing installations in the Val Verde area get about 1.3 Mt./yr. of CO2 for use in EOR facilities at the Sharon Ridge oil field. The CO2 concentration of the incoming gas stream at the Val Verde plant ranges from 25 to 50% [5].

Under evaluation phases, there are eight big CO2–EOR projects. Nearly 63% of them are planned in China irrespective of the reality that tight continental geology and heavier oil are important factors [5].
