The basis for 4D - geomechanical modeling are 3D - geomechanical and hydrodynamic models. Hydrodynamics describes the movement of fluid in the reservoir, and geomechanics describes the deformation and movement of rock. By integrating these approaches into a single model, it is possible to predict changes in reservoir properties due to technological impact with high accuracy.
To create a combined geomechanical-hydrodynamic (4D) model, the distribution of pore pressure over the entire simulated volume, obtained from hydrodynamics, is used in a 3D geomechanical model. Geomechanical parameters and stresses are calculated for various pressure values.
In the case of a two-way connection between hydrodynamics and geomechanics, the parameters of the geomechanical model calculated at a certain pressure are used as input data in hydrodynamic calculations, thus starting a two-way iterative process.
4D modeling uses a wide range of field information. Well log data with rock properties, core test results, direct pressure measurements, production information provide an opportunity to make an accurate calibration and provide a high predictive power of the created model.
4D - geomechanical models, allow you to effectively analyze the impact of production on spatial changes in reservoir pressure, geomechanical parameters, saturation and reservoir permeability and predict the behavior of developed reservoirs. Using the results of 4D - modeling, you can make:
- Forecast of changes in the magnitude and direction of stresses in the reservoir
- Permeability change calculation
- Calculation of the change in loss and collapse gradients of the wellbore over time
- Evaluation of formation failure and sand production
- Forecast of subsidence and reactivation of faults due to production
- Caprock Integrity Analysis
Based on the forecast obtained, the expediency of development is determined and the optimal strategies and technologies for production are selected. The drilling carpet, well designs, completion systems and production modes are being optimized to maximize the accumulated flow rate.
