Flow diagnostics for naturally fractured reservoirs

Carbonate reservoirs contain much of the world’s remaining hydrocarbon resources. These reservoirs are challenging to characterise and forecast production due to uncertainty in the fracture distribution and wettability. Ideally a large number of models needs to be simulated to quantify uncertainty but, due to time constraints, typically only a small subset of scenarios is considered. A dual-porosity module with a flow diagnostic toolbox has been implemented into MRST by the Carbonate Reservoir Group at Heriot-Watt University. The new diagnostics provide useful information that approximates the reservoir dynamics and matches full-physics simulation results, but can be obtained in a fraction of the time needed for simulation. Using flow diagnostics hence enables the fast screening and ranking of vast numbers of static models for fractured reservoirs. This enables us to consider the full range of geological uncertainty whilst minimising the number of models required for traditionally heavy simulation tasks such as, production forecasting, optimisation and uncertainty analysis that rely on full-physics simulations. Flow diagnostics hence complement and extend knowledge obtained from conventional fractured reservoir characterisation, calibration, and simulation workflows.