Print this pageGeochemical Modeling of the Rancheria Basin, Colombia
The Ranchería sub basin is located in the northwest region of Colombia, it’s part of the Cesar-Rancheria Basin which is a foreland basin formed by northeast-southwest compressive strengths. Major uplift events due reverse faulting took place in several phases. The first phase started on the Eocene, the second uplift happened during the Oligocene, the final configuration of the basin occurred during the Neogene.
The objective of this study was to determine the oil and gas potential in this sub basin using 1D, 2D and 3D geochemical models. The main exploration plays are: the fractured Cretaceous limestones of the Luna and Cogollo Formations, and Tertiary coal-bed methane reservoirs of the Cerrejón Formation. The Cogollo Group and La Luna Formation are the Cretaceous source rocks. These formations have excellent generation potential with kerogen types II and III, TOC ranging between 1 and 4.5% and vitrinite refelctance between 1 and 2%.
Geochemical models of 1D, 2D and 3D shows that the lower Tertiary Formations enter the gas window 15 Million years ago to the present and the Cretaceous Formations enter the oil window 30 million years ago.
The 3D geochemical model shows the possible accumulation of 31.35 BBOE, in the entire sub basin. The main risk of these conventional and unconventional prospects is the presence of an effective seal on top of the coal-bearing units and the cretaceous units, which in some areas is not thick enough to trap gas and oil. The structural maps of the lower Tertiary and Upper Cretaceous formations shows potential plays in several areas of the basin, these possible plays are the result of the thrust faulting systems.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil