Characterization and Modelling of a Reservoir with Multiple Scales of Fracturing

An integrated fracture study from characterization to modelling on a carbonate field is described. This oil and gas accumulation is produced through 6 horizontal wells. Outcrop data allowed us to understand the spatial organisation of fractures seen on well imagery and to identify the main fractures scales: bed confined (BCF) in tight layers, highly persistent (HPF) and conductive faults. Two orientations have been identified at both BCF and HPF scales: axial N70 fractures related to the folding and N150 fractures uniformly distributed throughout the reservoir. Mud losses have been used to rank the conductivity of the different scales encountered at the well and PLTs have shown a clear relationship between fractures and productivity. A correlation between KH from PBU and N70 FF has emphasized the key dynamic impact of the HPFs. The fracture modelling has been performed using a DFN and has focused on HPFs. A fracture permeability grid data has been processed by the DFN and was used as an input for a double porosity model. The shape factor derived from well imagery data was lowered to match the historical GOR. This is thought to be due to the heterogeneity in dynamic properties of the HPF set.