Modeling of Multiphase Flows in Porous Media With Applications to Reservoir and Well Performance Analysis

Abstract

The present work concerns the development of a comprehensive model capability in ANSYS CFD software FLUENT towards modeling of multiphase flows in porous media with targeted applications in reservoir/well analyses. The modeling approach is based on the Eulerian multifluid model. Porous media are modeled by both Superficial and Physical Velocity formulation with embedded sub-models to account for the resistance sink, relative-permeability and capillary pressure effect. An advanced numerical algorithm has been developed to achieve time-step and mesh independent solutions as well as to satisfy the physical constraints/limits. In particular, the resistance sinks are rearranged and linearized to ensure numerical stability and to handle mathematically infinite resistance caused by possible zero relative permeability. The capillary pressure and body forces are implicitly treated to enhance solver robustness. The multiphase porous medium model is compatible with all the numerical schemes and solvers (iterative and non-iterative) available in FLUENT. The present model has been applied to simulate 1D, 2D and 3D transient oil-water two-phase flows mimicking the conditions in reservoirs and wells. The solutions are time-step and grid independent, and successfully reproduce the flow characteristics and physical limits. The solvers are fast and robust, allowing the time step to be as large as 2 hours for a reservoir setting with the flow physical time in 2–20 years. The model capability shows great promises for reservoir and well performance analysis.

Multiphase coupling of a reservoir simulator and computational fluid dynamics for accurate near-well flow

“…The method is known as the One-Domain Approach (ODA) [30,31], and it has been implemented in several commercial multi-purpose softwares. The Navier-Stokes continuity equation for an isothermal, compressible and immiscible two-phase fluid can be stated as [32]…”

Numerical Simulation of Flow Through Absorbing Porous Media Part 1: Rigid Porous Media

“…The Finite Volume Method (FVM) is rarely used while modelling the wicking flow in porous media using the homogenised porous media approach. Li et al (2016) modelled the multiphase flow in porous media using the Eulerian approach. The main objective of their study was to analyse the performance of a reservoir and wells.…”

“…There is evidence that the FVM can be applied along with the Eulerian method to model the liquid absorption process. However, in this case, a lot of fitting parameters needs to be estimated with a series of experiments or simulations, and it might become difficult to model the liquid absorption process accurately if these parameters are not known correctly (Diersch et al, 2011) (Li et al, 2016).…”