--> Abstract: Hydrocarbon Potential of the Formations of the Basal Calcareous Group in a Sector of the Eastern Cordillera, Province of Santander, Colombia, by Delgado Blanco, Leidy A. and Luna Osorio, Juan S.; #90166 (2013)

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Hydrocarbon Potential of the Formations of the Basal Calcareous Group in a Sector of the Eastern Cordillera, Province of Santander, Colombia

Delgado Blanco, Leidy A. and Luna Osorio, Juan S.1
1[email protected]

The current research was performed to study the hydrocarbon potential of Lower Cretaceous rocks, also known as 'Basal Calcareous Group' to which belong the Rosablanca, Paja and Tablazo formations. In this study they emerge in the East zone of the Eastern Cordillera in Colombia.

First in the Rosablanca Formation exist 3 types of facies; micritic limestone facies, biomicrite limestone facies and shales facies. On the other hand, the results of geochemical analysis performed on samples of limestones and shales of Rosablanca Formation show that it is thermally over mature since the Tmax varies between 476-512°C. At the same time, the content of Total Organic Carbon (% TOC) varies from 1,0 to 4,8 indicating a very good potential for hydrocarbon generation. For this formation, vitrinite reflectance data could not be taken.

In second place relating to the Paja Formation are 2 types of facies; micritic limestone facies and shales facies. The geochemical data on samples of limestones and shales of the Paja Formation show that it is in over mature state with Tmax ranging from 491-588°C and has %TOC values between 1,0 and 4,3 indicating good potential for generating hydrocarbons. On the other hand the vitrinite reflectance could not be measured.

Lastly in third place in the Tablazo Formation are 2 types of facies; micritic limestone facies and shales facies. Also geochemical analysis for samples made of limestones and shales in the Tablazo Formation indicate that this state is already over mature since Tmax varies mostly between 511 to 595°C, the values of %TOC are in a range of 1,0 to 1,8 indicating a regular potential of hydrocarbon generation. Besides, the reflectance of vitrinite also indicates that the Tablazo Formation is in an over mature state because the values are in a range of 2,0098 to 2,7157% Ro.

Finally It is considered that this area may have limited interest for unconventional reservoirs of shale gas type because some data can overcome the dry gas window with elevated Tmax would lead to think that organic matter has been completely burned. However, in the west zone of the eastern cordillera where the basin has suffered less burial, these formations could have a very good TOC content and also the Tmax and Vitrinite reflectance could be more prospective for hydrocarbon generation, so we conclude that the West zone of the Eastern Cordillera could have great potential for unconventional hydrocarbon generation.

 

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013