Assessment of linking damage zones of geological faults through numerical modeling

Assessing damage zones is essential to support strategic decisions that ensure operational efficiency and the safety of exploration and production activities in the oil and gas industry. This study presents a numerical methodology based on the finite element method with rock elastoplastic behavior for predicting the linkage and interaction of damage zones triggered by one, two or more faults at the pre-salt level. First, we use conceptual models to assess the deformation mechanisms in linking damage zones and analyze how the choice of the constitutive model and the relative distances between two faults affect the damage zone prediction. The results show the relative position given by the separation and the overlapping of two faults determine whether extensional or contractional mechanisms form. Furthermore, the analysis must consider more comprehensive models capable of simulating shear compaction for the latter. Then, we applied the methodology in a case study in a pre-salt field aiming to assess interaction damage zones. Seismic data provides the geometry of horizons and fault surfaces while well data brings the type of deformation structures present in fault damage zones. The numerical results indicate the formation of extensional interaction damage zones resulting from a sinistral strike-slip combined with the normal movement of faults. Well data corroborate this finding by indicating the presence of hydraulic breccias. The analysis of both conceptual models and the case study demonstrates that the proposed methodology can be used with industry data to predict the formation of damage zones.