Qualitative schematic models of the Mishrif Formation, which have previously dominated the research, are inadequate for predicting reservoir production performance due to their inability to quantify spatial heterogeneity. In contrast to these earlier approaches, this study integrates core analysis, wireline logs, and 3D seismic data to not only describe but also quantitatively characterize the depositional elements and their spatial distribution. A novel methodology was developed to define nine distinct depositional elements from cored wells and then continuously identify them in uncored wells using unique pseudo-wireline log responses, a step not achieved in prior work. Furthermore, moving beyond previous qualitative models, 3D quantitative versions were constructed using Sequential Indicator Simulation (SIS) explicitly constrained by depositional geometries derived from 3D seismic inversion volumes. For the first time, these models reveal the quantitative spatial extent and evolution of these elements. Updating the 3D petrophysical property model using this new depositional framework resulted in a 15% increase in successful production history matches, demonstrating the direct and superior predictive power of this integrated quantitative approach for forecasting oil reservoir production performance.