--> --> Abstract: A Regional Overview of La Luna Formation and Villeta Group as Gas & Oli Shales in the Catatumbo, Magdalena Valley and Eastern Cordillera Regions-Colombia, by Veiga, Ricardo D. and Dzelalija, Francisco; #90166 (2013)

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A Regional Overview of La Luna Formation and Villeta Group as Gas & Oli Shales in the Catatumbo, Magdalena Valley and Eastern Cordillera Regions-Colombia

Veiga, Ricardo D.1 and Dzelalija, Francisco
1[email protected]

The Cenomanian-Turonian marls and shales of La Luna Formation and Villeta Group show excellent conditions as promising gas & oil shales. A combination of high TOC, high maturity, good thickness and adequate depth allows exploring these units in different regions of Colombia.

In the Catatumbo Basin, La Luna Formation achieves 300 ft-thick, with a TOC around 4-5% and a maturity from 0.8 to 1.3%Ro. The richness calculated for La Luna Formation is around 9 MMboe/km² and 22MMboe/km². Several wells have tested to La Luna Formation as a secondary and fractured reservoir in the region; therefore brittle rocks could be expected in that area.

The Middle Magdalena basin seems to be the most prospective area based on maturity, richness and thickness.

In this region La Luna Formation reaches 1500 ft-thick, TOC values between 2 and 5 % and maturity around 0.5 and 1.3%Ro. In the same way, several wells have proved La Luna as a fractured reservoir with small production and reserves. The richness estimated in the Middle Magdalena could achieve 46 MMboe/km².

In the Upper Magdalena basin La Luna Formation is replaced by the Villeta Group and it can be divided into four units from base to top: Tetuan Limestones, Bambuca Shales, Middle Limestones (=La Luna Formation) and Aico Shales. A very good TOC content can be recognized in the Tetuan and La Luna, but the source rocks could be early mature. The same units are in the Eastern Cordillera but they have a slightly higher maturity. The most prospective areas are focused in the center of synclines where the maturity is higher due to the overburden generated by thick tertiary sediments. The richness estimated in that region could reach 27 MMboe/km². Mboe/km².

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