Caracterização de reservatórios não convencionais Shale Gas na Formação Barreirinha Bacia do Amazonas

Abstract

The Devonian black shale of Barreirinha formation is characterized by high radioactivity in the basal portion, large areal extension, thickness and depth of burial variable which ranges from exposure to surface to depth greater than 3000 m. This formation contains the main source rocks of conventional petroleum system of the Amazonas Basin, and recently were considered promising unconventional gas plays. Shales are generally characterized by a closed die, which makes them relatively impervious for gas flow unless fracturing occur, and depending on their geological and geochemical characteristics they might behave as a self contained Petroleum System, acting as both source rock and as a gas reservoir (Shale gas reservoir). Thus, the thermogenic or biogenic gas generated can be stored in shale rich in organic matter in free form, adsorbed or dissolved state. In contrast to conventional petroleum systems, Shale Gas reservoirs, have trapping mechanisms and unique storage, requiring the use of specific assessment techniques. However, prolific shale can usually be recognized based on some basic parameters: geological and sedimentary architecture, geochemical and petrophysical properties and mineralogical composition. Given the lack of descriptive research, about the exploration potential of the Barreirinha formation s shale, this dissertation aims to introduce a methodology of identification of intervals that could be potential shale gas reservoirs. Starting with a regional research about the geological and sedimentary context, followed by a comprehensive review focusing on the geochemical characteristics, petrophysical and lithofacies based on the integration of the parameters obtained by well log, geochemical analysis and application of Sequence Stratigraphy concepts.