Perpustakaan Digital ITB

Reliable estimation of aquifer water influx remains a persistent challenge in reservoir engineering, in undersaturated water-drive fields where inaccurate aquifer characterization can significantly bias reserve estimates and long-term production forecasts. Material Balance Equation (MBE) aquifer models each applies different assumptions regarding flow regime, boundary geometry, and time-dependent behavior, yet a systematic comparison of their physical and mathematical performance on the same field remains limited. This study aims to (1) analyze the performance of eight aquifer influx models Schilthuis, Hurst, van Everdingen-Hurst (VEH), Carter Tracy, Fetkovich, Allard Chen, Leung, and Small Pot from both physical (flow regime, geometry, boundary conditions) and mathematical (algorithm behavior, discretization error) standpoints during Pressure Matching in “B” Structure “S” Field, and (2) validate each model’s performance against the reservoir’s aquifer properties during Well-level History Matching. "B" Structure and "S" Field Stage 1 pressure matching produced RMSE values ranging from 10.5 to 30.2 psi across the eight models, with models assuming edge-water drive and radial geometry, i.e. Hurst, Leung, and VEH consistently outperforming those built on instantaneous equilibrium, zero diffusive delay, or bottom-water vertical flow assumptions. Havlena Odeh diagnostics reinforced this pattern, confirming that physical compatibility with the aquifer’s true flow regime, rather than mathematical complexity alone, primarily governs pressure-match accuracy. Stage 2 history matching, which validated each model against the reservoir’s well-level production response, showed that models physically consistent in Stage 1 carried their accuracy forward to its cumulative production matching, while models determined as physically inconsistent failed to reproduce accurate well level behavior regardless of subsequent parameter tuning. These results demonstrate that optimal aquifer model selection depends on physical consistency with the reservoir’s actual flow regime and boundary geometry along its numerical robustness for the most reliable dual-stage history match. As such “B” Structure and “S” Field is confirmed to have edge-water drive and radial-geometry models.