Modelagem geológica e simulação de fluxo em arenitos deformados afetados por silicificação na Bacia Rio do Peixe.

Abstract

Siliciclastic petroleum reservoirs are major global sources of hydrocarbons, frequently affected by diagenetic and structural processes such as silicification and deformation bands. Accurate identification and characterization of these features are essential to optimize reservoir exploitation and minimize environmental impacts. Considering this need, the use of outcrop analogs to petroleum reservoirs has significantly contributed to the modeling of petrophysical properties in porous media, facilitating the understanding of subsurface reservoirs. However, the application of flow simulation to better understand these processes remains underexplored. This study aimed to investigate the variation of petrophysical properties within the damage zone located in the hanging wall of the Portalegre Fault, a border fault of the Rio do Peixe Basin. Modeling tools and numerical simulation techniques were employed to analyze the impact of such features on fluid flow. The elements considered in the characterization of this fault zone included silicification intensity and the presence of deformation bands, based on prior studies. The data analysis enabled the construction of a structural model of the area, subdividing it into three distinct zones toward the fault core: Zone I – Non-silicified sandstone; Zone II – Intermediately silicified sandstone; and Zone III – Intensely silicified sandstone. An initial porosity model was created and used as a trend for generating final porosity and permeability models, which were subsequently applied in flow simulations. The final porosity and permeability models exhibited an inverse correlation with silicification intensity, following a gradient that increased toward the non-silicified zone. Zone I showed significantly higher oil recovery values compared to the others, averaging around 34%. The flow lines highlighted the influence of silicification on flow direction within the reservoir. Silicification in the fault zone generated preferential flow paths perpendicular to the fault, overriding the control exerted by deformation bands. These findings enhance predictive capabilities regarding fluid flow and support the optimization of production strategies in siliciclastic petroleum reservoirs.