2019_EJRNL_PP_SEYED_ERFAN_SABERHOSSEINI_1.pdf
Terbatas Resti Andriani
» ITB
Terbatas Resti Andriani
» ITB
Pre-analysis of the geometry and deviation of multiple hydraulically induced fractures is a decisive factor in the
successful multiple hydraulic fracturing operations. Besides, fracture spacing should be optimal for obtaining
desired results such as maintaining sufficient aperture for proppant placement, avoiding screen-outs and also
preventing fracture closure or crossing multiple fractures. In fact, the final geometry and deviation of multiple
hydraulic fractures are dramatically influenced by the interaction of multiple hydraulic fractures on each other
known as stress shadow effect which is caused by fracture spacing and pore pressure change. Predicting the
geometry and deviation of multiple hydraulic fractures is a challenging part of conducting this technology in
Ilam reservoir due to low matrix permeability and naturally fractured nature of the reservoir. Accordingly, a
fully coupled stress-diffusion XFEM model for initiation and propagation of multiple hydraulic fractures with
five injection zones was prepared to optimize the effect of fracture spacing and pore pressure change on the
multiple hydraulic fractures’ deviation and geometry. Additionally, the XFEM model was verified by three approaches including field data, Stress Intensity Factor and KGD zero toughness solution wherein a very good
agreement with negligible error was obtained for SIF, field data and KGD M-vertex solution. However, this study
has confirmed that both pore pressure and stress shadows contribute to change the fracture geometry and its
deviation significantly in Ilam reservoir. Also, increasing pore pressure between fractures, may affect the fracture
geometry to be tighter in width and shorter in length. In addition, considering optimized fracture spacing about
75 m resulted in creation of very smooth, uniform and deeper multiple hydraulic fractures; so, there will be no
closed fractures in DPH-02 horizontal wellbore and the possibility of crossing the furthest fracture by the second
fracture significantly reduced when the fracture spacing was higher than 5 m.