Paper Title
Assessment of Hydraulic Fracturing in Tightreservoirforco2 Geological Storage

Abstract
Fracture initiation and propagation could occur if the CO2 pressure exceeds the closure stress by CO2 injection in tight reservoir. Propagation of hydraulic fracturing in the vertical direction is unfavorable as it imposes leakage risk, while propagation in the horizontal direction could be favorableas it will make the increase of the CO2 injectivity and storage capacity. The existence of fractures could also be beneficial as it will mitigate a sharp pressure increase by CO2 injection.This paper presents the assessment of CO2 storage capacity considering geomechanics through hydraulic fracturing in tight reservoir.Hydraulic fracture propagation simulations were performed to evaluate the effects of the brittleness on fracture propagation behavior by CO2 injection. The used model implements a multiple planar fracture approach with mixed mode, the fracture crossing criterion used to predict whether the hydraulic fracture will cross the natural fracture in the model. This criterion and the amount of storable CO2 volumes were compared for fracture modes of opening and mixed in various brittleness index. As a result, Young�s modulus is the more sensitive factor than Poisson�s ratio on fracture crossing angles. With larger brittleness index, the CO2 storage capacity was calculated to be larger because fracture crossing occurred easily.It can be helpful for safety assessment of CO2storage projects. Index Terms: CO2 storage capacity, Hydraulic fracturing, Brittleness index, Sliding mode, Tight reservoir.