Efeito das estruturas de linkagem no fluxo de fluidos em zona de falha de bandas de deformação na Bacia Rio do Peixe, Nordeste do Brasil.

Abstract

The main objective of this work is to analyze the effect of hard-linking structures, associated with the coalescence of deformation bands in a fault zone, on the reservoir properties and how they will influence the fluid flow of a siliciclastic reservoir. Therefor, we selected an outcrop in the Rio do Peixe Basin, where petrophysical (permeability and porosity) and structural data (direction, frequency, thickness, and typology) were collected, compiled, and subsequently applied to generate four reservoir models. These models were applied in flow simulation using streamlines for two different development strategies, with an oil-producing well and a water injection well. Biweekly reports were generated, for a production period of 10 years, covering the visualization of fluid saturations and production parameters. The permeability analysis showed that the deformation intensity is inversely proportional to the sandstone permeability. Furthermore, we evidenced that the incidence of deformation bands is a factor that generates anisotropy of permeability in the host rocks, with the measurements performed parallel to the dip of the bands the ones with the highest permeability, while the measurements performed orthogonal to the dip of the bands the ones with the lowest permeability. Based on strain intensity (DB/m), we propose a new classification of fault facies to represent fault zones of strain bands: facies A (> 11 BD/m); facies M (10-6 BD/m); facies B2 (5-2 BD/m); facies B1 (2-1 BD/m); and facies ND (0 BD/m). We analse the spatial relationship of fault facies, and we observate that they have lateral distribution. We also see that facies A and M are associated with cluster zones. Besides that, we have seen that hard-linking deformation bands have more impact on produtivity when compared to single structures. We show that a fault zone composed of deformation bands will not compartmentalize an oil reservoir, but it will restrict the flow through the fault zone. For the four scenarios analyzed, the presence of deformation bands was responsible for anticipating the water breakthrough, reducing the volume of recovered oil, and increasing the water production from an oil reservoir. These factors were influenced by the channeling promoted by the architecture of the band network and its specific characteristics. We conclude that the deformation will negatively impact the productivity of oil reservoirs when analyzing the production through the fault zone.