**5. Possible applications of the method CCUS–EOR IN the EASTERN LLANOS basin (Colombia)**

In general, the actual Eastern Llanos basin is a suitable basin for the storage of CO2–EOR because it meets the criteria mentioned above, such as 1) natural gas and oil production, 2) extensive basin with hydrodynamic traps, and 3) several reservoir formations with good regional confinement. To this is added that oil fields are varied and extensive, and a considerable number of these hydrocarbon exploitation projects are in the maturation stage where it is necessary to increase the production of hydrocarbons through improved recovery and thus prolong their useful life (**Figure 5**).

"*The Eastern Llanos Basin is the most prolific hydrocarbon basin in continental Colombia. The northern boundary of this basin is the Colombian–Venezuelan delimitation; to the south, the basin goes as far as the Macarena high, the Vaupés Arch and the Precambrian metamorphic rocks that outcrops to the south of the Guaviare river; the east limit is marked by the outcrops of Precambrian plutonic rocks of the Guyana Shield, and to the west, the basin is restricted by the frontal thrust system of the Eastern Cordillera*" (**Figure 5**) [11].

A schematic drawing cross section of the Eastern Llanos basin shows that the oilrelated formations are of Cretaceous, Paleogene, and Neogene ages, between the Eastern Cordillera westward and the Brazilian craton eastward (**Figure 6**). The Eastern Llanos is a complete foreland basin that changed when the Andes were pushed to the east against the South American plate. The structural surroundings allow the geological formations in the basin that stayed mostly planar and undisturbed, fashioning them favorable for CO2 sequestration.

*Carbon Capture, Use and Storage (CCUS) as Enhanced Oil Recovery (EOR): Llanos Orientales… DOI: http://dx.doi.org/10.5772/intechopen.105949*

*The Eastern Llanos basin located in the bigger Orinoco River basin in northern South America.*

#### **Figure 6.** *Cross section of the foreland Eastern Llanos basin [11].*

Basin development began in the Paleozoic with rifting. Clastic materials were sedimented over the Precambrian basement from the Triassic time to the Late Cretaceous. The basin was the oriental block of a major rift system. From the Maastrichtian to the Paleocene time, the Llanos basin developed into a foreland. During the Neogene, the basin has been a deposit of thickened molasse sediments. The source rocks are Cretaceous, and span from immature to marginally mature eastward of the frontal

thrust. The main deposits are clastic units of the Late Cretaceous and Paleogene ages. Investigation of the individual elements of the migration arrangement inside the basin is complex because of the thinning of the stratigraphic segment and the evolution of more sandy facies in the direction of the Guyana Shield [9].
