NUMERICAL MODELING OF HYDRAULIC FRACTURE PROPAGATION USING FEA IN SHALE RESERVOIRS

Resumo

The aim of fracking procedures is enhancing the permeability of non-conventional reservoirs. This
process is influenced by the in-situ stresses. Throughout history, in Vaca Muerta (Argentina), wells production has

been technically challenging. Vaca Muerta formation is made of shale and limestone layers which induce a dif-
ference in the in-situ stresses. In a strike-slip regime this stress difference in combination with the geomechanical

properties might promote the appearance of horizontal fractures. Given the above, the following research discusses
numerical modeling of the stresses during the fracking procedure.
Several numerical experiments will be presented to identify opportunities to optimize operations in Vaca
Muerta, considering different features, such as: geomechanical properties, weak interfaces (density and properties),
and laminations (shale vs limestone).
This work presents numerical results concerning the growth of a vertical hydraulic fracture in a 3D shale
domain. This fracture growth is limited by a thin layer of limestone, which creates a weak interface between the
limestone and shale. The goal of this analysis is focused on the interaction mechanism between the weak interface
and the growth of the vertical fracture. Arrest, crossing and T-shapes fractures can take place. A cohesive mode
with mixed damage is carried out. Furthermore, this study explores different properties for the limestone layer,
given by a geomechanical model from Vaca Muerta, effect in fracture growth. Results will provide an optimized
operating window for injection and fracture process in order to improve the resultant stimulated reservoir volume.