Avaliação do potencial volumétrico dos folhelhos betuminosos da Formação Tremembé, Bacia de Taubaté

Abstract

The study of the volumetric potential of the shales of the Tremembé Formation, carried out herein, was based on the sedimentological and geochemical study of core samples taken from the central portion of the Taubaté basin. Based on analyses of facies, geochemical COT data and Rock Eval pyrolysis data of 2,457 core samples from nine wells from the central portion of the Taubaté basin, thirteen chemostratigraphic units were defined within a package approximately 240m thick, in the upper portion of the Tremembé formation, each with thickness from 10 to 35m. The uppermost interval (unit L), approximately 30m thick, exhibited the highest organic content and original generation potential, thus was studied in greater detail.Unit L was subdivided into seven subunits (L1 to L7, from the base upwards). Among these, subunits L5 and L7 were identified as the most important in terms of quantity and quality of organic matter. Yield maps were configured with the objective of identifying the most attractive areas for the industrial recovery of oil shale resources. Then, volumetric assessments with Monte Carlo probabilistic methods were carried out to quantify the potentially recoverable volumes of oil. Subunit L7 exhibited the highest quantity and quality of organic matter, reaching significant volumes of potentially recoverable oil. Three exploratory scenarios based on yield values (S1 + S2) were considered for volume calculations, seeking to present different exploratory decision-making situations. For the scenario of average yields above 100 mg HC/g rock, the recoverable oil volume was estimated to be 483 million bbl (P90) to 803 million bbl (P10). For the scenario of average yields of 80 mg HC/g rock, the recoverable oil volume was estimated to be 1.4 billion bbl (P90) to 2.3 billion bbl (P10).For the scenario of average yields of 60 mg HC/g rock, the recoverable oil volume was estimated to be 3.2 billion bbl (P90) to 5.0 billion bbl (P10)