Pore Scale and Reservoir Modeling for Near Miscible Three-Phase Flow Gas/WAG Flooding Reservoir
Authors: Gibrata Muhammad A , Hashem Mohamed 
Published: November 2017

Reliable of pore scale and reservoir modeling in reservoir with water alternating gas (WAG) flooding is challenging and important for getting an accurate reservoir characterization, enhanced oil recovery (EOR) and reservoir management. Inaccurate characterization and modelling of these reservoir properties and fluid will lead to high uncertainty of reservoir characterization, minimum oil recovery and reservoir management concerns. Hence it is useful to predict and assess effects on pore-scale and EOR of field scale.

Research has been performed in carbonate reservoir with near miscible three-phase flow of water alternating gas (WAG) injection activity. It has several challenges: near miscible three-phase flow modeling, effects of different three-phase relative permeability models on field-scale recovery for different wetting systems and fluid properties at immiscible and near miscible and quantify impact to oil recovery.

The comprehensive pore-scale and reservoir modeling approach is required by the integration of various sources such as those from petrophysical and geological data. Utilize the 3D network structure of representative reservoir rock properties. In prediction and guide SCAL based; investigation the effects (sensitivity) of interfacial tensions, contact angles, wettability, spreading coefficient, balance of viscous and capillary forces into miscibility on the oil layers between gas and water in a fully interconnected three-phase flow pore-network model. Utilize thermodynamic criteria for rock properties and oil layers, which affect the oil relative permeability for accurate prediction of residual oil and maximize oil recovery.

I have used an integrated pore scale and reservoir models workflow: establish pore network model, validate with SCAL, up scale to well logs, utilize formation pressure/sampling/testing and combine with structural data of geology-seismic and perform history match of the reservoir dynamic modeling. The effect of balance of capillary and viscous forces in pore scale have been evaluated in the research. It has provided a reliable properties for a reservoir dynamic model.

In the research, i have used similar range of reservoir and fluid properties such as pore throat size in reservoir range for pore network model. I analyze pore scale and field scale oil recovery during WAG at immiscible and near miscible condition to generate the three phase relative permeability models. The simulations at the reservoir scale shows that the highest oil recovery for the water-wet is obtained by injecting near miscible gas. Recovery increased by over 10% during WAG injection in agreement with typical values on SCAL and pore network models.

The comprehensive approach of near miscible three phase flow WAG in pore network model, core-logs validation and the reservoir model are important in reservoir modelling. The integration is used for getting an appropriate relative permeability, capillary pressures and water saturation in near miscible Gas and Water Alternating Gas (WAG) flooding of reservoir. Thus it can give an accurate and robust of reservoir characterization, maximize oil recovery and optimum reservoir management.