The Armatella Field in SE Sicily is structurally complex with two fractured, carbonate reservoirs containing heavy-oils, with the heavier hydrocarbon overlying the lighter one. One well has been drilled in the field – a vertical pilot completed with two opposite, stacking, open-hole horizontal drains. A complex compositional evolution of the fluids produced has been observed. A reservoir study integrating geophysics, geochemistry, petrophysics and reservoir engineering assessed the reservoir geometry and the field production behaviour. This allowed the identification of two different phases of hydrocarbon migration that were geologically constrained according to the structural evolution of SE Sicily. The 3D structural reconstruction of the field, built with a Shared Earth Model, was utilized as input to a 3D dual porosity numerical model. The dynamic simulation allowed identification of the drilling location of an additional non-conventional well aimed at draining undeveloped reserves. The study used advanced laboratory methodologies for fluid characterization, state-of-the-art methods for analysing the reservoir fracture network and properly designed modules for simulating non-conventional completions in a 3D dynamic model.