Total Play Fairway Analysis of Unconventional Cretaceous Plays in the Eastern Cordillera, Colombia

Leonard, Jay E.¹; Passos Giraldo, Sandra; Marcano, Fernando; Gyorfi, Istvan; Heydweiller, Erich C.; Zamora, Lucas; and Lilliu, Antonello
¹[email protected]

Over the past several years, unconventional resource plays have taken a significant role in hydrocarbon exploration. When the methods, elements, and results of these plays are combined with conventional methods and elements we create a compound play which is best characterized by Total Play Fairway Analysis (TPFA). This is exceptionally well demonstrated in the Los Llanos basin.

We will present the results of a total play fairway analysis conducted to evaluate the potential for oil and shale gas in the Eastern Cordillera of Colombia. The specific area of the study is between the Boyacá fault and Soata-Cocuy Sur faults, and covers the Muisca, Cord-15 and Cord-24 license blocks. Input to the total play fairway analysis includes interpretation of the regional geology and petroleum systems modeling; the method also considers the quantity and quality of the data in the determination of numeric chance of success.

Most of the hydrocarbons in the area and to the south in the Los Llanos basin have been generated from the Cretaceous Chipaque Fm., a Luna Fm. equivalent. The well-known conventional play is associated with production from Cretaceous and Tertiary sandy reservoirs.

The unconventional play of this system is defined as a self-sourced, low-permeability reservoir where oil or gas are stored in: (1) intercrystalline pores, (2) nanopores created from organic matter decomposition, and (3) adsorbed on kerogen molecules. This unconventional play has yet to be tested. This study assesses the presence and effectiveness of both the Chipaque Fm. and the Fomeque Fm. as source rocks and low permeability reservoirs.

Measured and modeled maturity values range from 0.6 to 1.6+% vitrinite reflectance across the area. Thermal modeling accounts for the tectonic history of the Eastern Cordillera, including the Triassic to Early Albian rifting events, as well as erosion related to Andean uplift. The complex uplifting of the Eastern Cordillera is supported with balanced cross sections based on the interpretation of major thrust fault systems – these are integrated into burial histories. Erosional thicknesses are estimated to be 4000-6000 feet. Calculation of generated hydrocarbons considers primary and secondary cracking of kerogen and retained oil.

Calculation of retained hydrocarbons in the SR reach to >200 Mbbls/acre rock of oil in areas at the West, and >300 Mcf/acre rock of gas in the West and South West, for a Type II source rock.

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