Modelo de condução de calor aplicado em sistemas petrolíferos atípicos: Formação Irati - Bacia do Paraná

Abstract

In the Paleozoic sedimentary basins, with the opening of the South Atlantic Ocean in the Mesozoic Era, significant basaltic outpourings occurred, covering various sedimentary basins worldwide. This event gave rise to Large Igneous Provinces (LIPs). In the Paraná Basin, this magmatic event, known as the Serra Geral magmatism, led to the formation of an unconventional petroleum system through the emplacement of sills and dikes among the sedimentary rocks. The Irati Formation is part of this atypical petroleum system, with horizons consisting of shales with a substantial amount of organic matter interspersed with diabase sills. The objective of the study was to obtain the thermal evolution of the basin using data acquired from two wells located in the municipalities of Santiago, Rio Grande do Sul, and Tangará, Santa Catarina. Paleotemperatures were estimated using the general equation of one-dimensional heat conduction in transient regime, implemented through implicit finite difference numerical methods along with the fourth-order Runge-Kutta method, in PYTHON language; following the model proposed by Galushkin (1997). It's important to note that the model does not take into account heat dissipation processes. The results indicate that Thermal Alteration Indices correspond to the thermal evolution obtained by the proposed conduction model. The obtained results reveal that the sills of the Irati Formation developed mature and senile zones along both wells. It was also observed that the thickness of the intrusions leads to different stages of hydrocarbon generation due to the amount of heat transferred from the intrusions to the host rocks over time, forming horizons with a high potential for hydrocarbon generation.