FREITAS, R.; http://lattes.cnpq.br/2432050702766499; FREITAS, Raquel Bezerra Rodrigues de Melo.
Resumo:
Topological analysis can help in structural characterization, as well as in understanding
the influence of connections on flow properties in reservoir rocks affected by
deformation bands. In the present work, we used a three-dimensional exposure (wall
and floor) of a fault zone in the Rio do Peixe Basin, Northeastern Brazil, to evaluate
the influence of connections on permeability. From detailed structural mapping, we
analyze the topological pattern of deformation bands. Additionally, we performed in
situ permeability measurements. The combination of structural data with permeability
data allowed us to investigate the influence of the connectivity of a deformation band
network and its impact on fluid flow properties in a fault zone. The results showed the
variation of the connectivity pattern along the fault zone, with the core presenting Y>I>X
pattern and the damage zone Y>X>I. We observed that in the core, the highest
permeability values were recorded at I - nodes, followed by Y- and X- nodes. In the
damage zone, there is an anisotropic variation, where the exposure wall registers
higher permeability for I - nodes and secondarily for Y- and X- nodes, while on the floor
the highest permeability was recorded at I - nodes and secondarily at X- and Y- nodes.
In addition, new nodes (with five and six branches) formed from the crossing of two
fault systems formed in different tectonic phases of the basin (sin-rift and post-rift) were
identified. This study contributes with new perspectives about the influence of
deformation band connections on permeability in a fault zone. This information may
imply the modeling and simulation of siliciclastic reservoirs affected by fault zones,
because possible to assess the impact of connectivity variation on fluid flow.