Geochemical Characterization and 1D Modeling in the Gulf of Venezuela

Abstract

A new petroleum system related to a giant gas and condensate has been discovered in the Gulf of Venezuela, specifically in the Cardon IV Block. In order to evaluate the elements of this new petroleum system, specifically, the source rock responsible for these fluids, a geochemical characterization was carried out in eight wells in the area. Additionally, 1D modelling was performed using PetroMod v2012® software, with the purpose of determining the maturity and expulsion ages of possible source rocks. The petroleum systems were affected by the tectonic history of the area. Six tectonic events, from Jurassic to Miocene, have been interpreted. Their influence on the different elements and process of the petroleum systems allowed the accumulation and preservation of hydrocarbons. Preliminary results indicate that the Lower Miocene (SMa) and Upper Miocene (SMc) sequences are those with characteristics to be considered as source rocks. The SMa sequence has a good potential for generating hydrocarbons (TOC: 0.95-1.73%, S2: 5-10 mgHC/g rock); it has a type II/III kerogen. On the other hand, the SMc sequence has good organic richness (TOC:1.11-1.70%); a medium potential for generating hydrocarbons (S2: 2.50-5.00 mgHC/g rock) and a type II/III kerogen. The maturity of the wells, determined by vitrinite reflectance measurements (%Ro) and by the maximum pyrolysis temperature (Tmax), indicate that the sequences of the Perla field are in early maturity (% Ro <0.60 and Tmax <435 ° C). Additionally, the 1D modelling of the wells indicates that the sequences have not generated hydrocarbons, due to their low thermal evolution. However, there is a basin area called “Surco de Urumaco” where the SMa sequence has reached sufficient thermal maturity to have generated hydrocarbons, It begins generating oil and gas at 13 Ma. Whereas the SMc sequence has not reached enough maturity to generate hydrocarbons. The results indicate that the hydrocarbons found in the Cardon IV Block were not generated in situ by the sequences studied, because they are immature. The hydrocarbons, were generated somewhere else in the basin where the source rocks have reached sufficient maturity. This place is probably in “Surco de Urumaco”.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016