RESERVOIR MODELLING AND UNCERTAINTY EVALUATION BY MEANS OF ALTERNATIVE STRUCTURAL SCENARIOS: THE ACCETTURA FIELD CASE OF STUDY (S. APENNINES, ITALY)

The goal of this dissertation is to quantitatively explore the uncertainties generated by the combination of geological information, seismic and wells and production data, linked to the building of static reservoir models. To face the evaluation of uncertainties, we adopt a multistep workflow: combining possible stratigraphic and structural interpretations in discrete scenarios; performing a 2D sequential restoration, generating alternative 3D models populated with reservoir properties and associated uncertainties. Alternative models have been then compared with production history, in order to check the consistency of the assumed models. The considered case of study is the Accettura Gas Field (AGF), located within the Garaguso Concession (held by Edison E&P) in the Bradanic Foredeep (BF) of the southern Apennines. We have considered unexplored structural solutions in order to figure out alternative scenarios on the structural control of the gas field. Four alternative scenarios of static reservoir models have been built for AGF and structural validation by balanced cross-sections across the BF were performed. A global uncertainty evaluation of the proposed scenarios was performed using stochastic techniques. The results show that the choice of structural model and the petrophysical properties impact the hydrocarbon deterministic and probabilistic volumetric assessment (Gas Initially In Place - GIIP) that affect both the estimate of mean volume and the range of uncertainty.