Modelagem geológica e petrofísica da zona de dano da Falha Malta na Bacia Rio do Peixe, NE do Brasil.

Abstract

The damage zone width and the permeability contrast between deformation bands and the interband spaces (host rock) impact the fluid flow in porous sandstones affected by fault zones. In this study, we model the damage zone extension in the hangingwall of a BRP (Malta Fault) bounding–fault and the distribution of deformation band intensity (DB/m), using fault facies modeling. We use from deformation band cumulative frequency data to delimit and model the damage zone subdomain boundaries and the frequency to characterize fault facies. Then, we integrated the permeability data, collected in the deformation bands and interband spaces (host rock), to model these properties conditioned to the damage zones and fault facies. Our results allowed us to characterize the deformation control in the permeability distribution of porous sandstones affected by faults. The deformation intensity (DB/m) proved to be important for the permeability analysis. For the subdomains of the most deformed damage zones or with a predominance of fault facies with high deformation band intensity, deformation bands and interband spaces show similar permeability reductions of up to 3 orders of magnitude compared to undeformed rocks, which occur low deformation or no deformation facies. This study carried out on the Malta Fault provides new insights into the deformation band permeability and interband spaces in different damage zone subdomains and fault facies. Thus, this research enables the modeling of equivalent permeabilities along damage zones, which has implications for siliciclastic reservoirs affected by fault zones, where deformation bands are the dominant brittle structures.