Evaluation of Hydraulic Fracture Propagation in Naturally Fractured Reservoirs

Abstract

This study aims to evaluate the hydraulic fracture propagation in naturally fractured reservoirs, to interpret its propagation models and to identify the behaviors associated with its propagation utilizing Nolte & Smith analysis and G-Function plots. A large portion of global oil and gas resources trapped in naturally fractured formations with low permeability. The low conductivity of the natural fracture networks requires a stimulation with hydraulic fracturing to make the economic production possible. Hydraulic fracturing in naturally fractured reservoirs is a complex process that presents numerous challenges and uncertainties. In most cases the hydraulic fracturing ends to failure due to the complex behavior of hydraulic fracture propagation in anisotropic milieu, and the miss understanding of the interaction between hydraulic fracture and natural fractures. In Algeria, there are several reservoirs considered as naturally fractured reservoirs such as in Gassi El Agreb and Hassi R’mel fields. These reservoirs have undergone operations of hydraulic fracturing in order to enhance their productivity and bypass wellbore damage. The common observations during hydraulic fracturing in naturally fractured reservoirs include high leak-off rate, low fluid efficiency, small fracture geometry, and unintended propagation beyond the target zone, even after stress calculations and data calibration.