Cronoestratigrafia e zoneamento de reservatórios das formações oficina e Merecure (Oligo-Mioceno), campos socororo e budare da Bacia Oriental da Venezuela

Abstract

The Socororo field is considered mature, despite his old and generally low quality database. That field did not produce in the originally calculated volumes, which implies in a field with potential to keep continuing oil production. The current study considers an important factor the understanding of the origin and distribution of sandstone intervals capable to hold hydrocarbons. Oilfields with fluvio-deltaic reservoirs display sandstone bodies that are vertically and laterally isolated by siltstones and shales. This sandstone architecture turns out difficult the well-to-well correlation of these potential reservoirs, and makes necessary the search for geological models. To evaluate the well log interpretation of Oligo-Miocene Merecure and Oficina reservoirs in Socororo field, it has been necessary to stratigraphically correlate it with nearby Budare field and also with a pilot project in Zuata area, which is part of Orinoco heavy oil belt. The geological model shows Merecure Formation to hold the major volume of sandstone bodies, while in higher positions the Oficina Formation is characterized by thin, sometimes isolated sandstone intervals, with lower frequency towards top of that unit. These characteristics were observed through chronostratigraphic correlation of fining-upward cycles and corresponding identification and mapping of five reservoir zones between Socororo and Budare oilfields and Zuata area of Orinoco belt.