High-resolution miscible and immiscible displacement calculations using multigrid and conservative unsplit multidimensional upwind methods in heterogeneous reservoirs
This research develops an integrated approach for high resolution characterization and high resolution transport modeling, specifically miscible and immiscible displacement, through geometrically complex subsurface reservoir systems. We apply a high resolution conditional indicator simulation technique to geometrically image the sand/shale heterogeneity of a study area in the Wilmington oil reservoir. This technique retains the integrity of the flow paths in the reservoir system. We also develop a high resolution two-phase miscible and immiscible displacement simulator that is applied at the full resolution of the geologic and geophysical data collected in the field. This simulator uses a robust computational splitting of the parabolic and hyperbolic equations for multiphase flow in a sequential formulation based on total velocity rather than individual phase velocities. Appropriate high resolution numerics are applied: multigrid methods are used to solve the elliptic pressure equation; while a multidimensional upwind method is used to solve for fluid saturation. The O(NlogN) convergence property of multilevel techniques persists in complex reservoir geometries and permeability variations of several orders of magnitude. Thus, the pressure calculation in sufficiently inexpensive permitting calculation of flow and transport at the resolution of available data. The multidimensional advection algorithm solves the discrete form of the hyperbolic conservation law. Because of the multidimensional design of the advection algorithm, fluxes are evaluated and differenced simultaneously so that strict conservation is maintained and numerical diffusion minimized. In our calculations, we see clearly defined displacement fronts that follow the flow path geometry and do not diffuse outside it. Our methods are observed to be substantially more accurate than first order upwind methods typically found in reservoir production codes.
- Research Organization:
- California Univ., Berkeley, CA (United States)
- OSTI ID:
- 5112228
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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