Uncertainty Analysis in Geological Modeling
Exploring the sources of uncertainty and the importance of uncertainty analysis in geological modeling
Introduction
- Uncertainty is inherent in geological modeling
- Static modeling software is used to create geological models
- Uncertainties include measurement accuracy, incomplete or missing data, and competition approximation
- Geological markers and sedimentary depositional environment also contribute to uncertainty
Sources of Uncertainty
- Measurement accuracy
- Incomplete or missing data
- Competition approximation
- Stochastic or probabilistic system
Petrophysical Uncertainty
- Permeability distribution
- Porosity distribution
- Water saturation
- Flirt contact location
Uncertainty Analysis
- Software enables uncertainty analysis
- Multiple realizations and scenarios are created
- Tornado diagram helps identify influential parameters
- Variogram analysis aids in estimating permeability distribution
Dynamic Modeling
- Conversion from static to dynamic model
- Reservoir engineering perspective
- Material balance model
- Tank models and reservoir simulation
Initialization and Initial Condition
- Equilibration method for initializing pressure and saturation
- Hydrostatic calculation for pressure distribution
- Saturation function for assigning saturation values
- Inital contacts and density calculations
Wrap Up
- Uncertainty analysis leads to more robust geological models
- Dynamic modeling brings the reservoir to life
- Integration of reservoir, well, and surface facilities
- Initialization sets the stage for flow simulation