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Thermogenic Hydrocarbon Processes In The Guajira Basin- A Petroleum Systems Approach
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 8th Simposio Bolivariano - Exploracion Petrolera en las Cuencas Subandinas, Sep 2003, cp-33-00030
Abstract
Thermogenic processes in the Guajira Basin, some with the potential of generate liquid hydrocarbons evidenced by recent geochemical and geological works, are reflected in at least four petroleum systems. These petroleum systems, provide a framework for exploration opportunities in northern Colombia. Macarao - Siamana P.S. (.): source rocks in the Eocene Macarao Fm. and reservoirs in the Siamana Fm, as proven towards the northeast part of the basin (Santa Ana area). Tertiary - Jimol/Uitpa P.S. (.): source rock in the Middle-Upper Miocene Castilletes Fm (thermally inmature), for biogenic gas. For the thermogenic hydrocarbon, the source rock is a thermally mature unit (Siamana or Macarao Fm). Reservoir rocks are the Lower Miocene Uitpa and Jimol Fms, producing in the Chuchupa-Ballena fields. Castilletes-Castilletes P.S. (?): source rock in the Middle to Upper Miocene Castilletes Fm, with reservoir potential in minor clastic developments. Mesozoic-Cretaceous P.S. (?): source rock in the La Luna-Cogollo Fms present to the east and northeast of the basin, with remnant potential in the Jurassic Cuiza Shale (Cosinas ridge area). Reservoirs would be fractured Cretaceous limestones, following analogy with Mara-La Paz Venezuelan fields. Hitherto the Guajira Basin has been regarded as a biogenic gas province, with a single petroleum system (some 6000 BCF of dry gas, 97% methane). Geochemical and geological data evidence that thermogenic processes are relevant in the evolution of the basin.. Therefore, in addition to the prolific gas character of these part of Colombia, an oil accumulation potential should be considered in the appraissal of its prospectivity.