New Developments in Multiblock Reservoir Simulation: Black Oil Modeling, Nonmatching Subdomains and Near-Well Upscaling

Lee, S.H.; Wolfsteiner, Christian; Durlofsky, Louis J.; Jenny, Patrick

doi:10.2118/79682-ms

Cited by 11 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Much of the material presented in Chapter 6 was presented in earlier Annual Reports to DOE (in Years 1 and 3) and also in papers (e.g., Mascarenhas and Durlofsky, 2000;Wolfsteiner and Durlofsky, 2002). The radial upscaling and multiblock simulation results reported here were presented earlier in Lee et al (2003). The two-phase near-well upscaling has not been presented previously (this work is part of Mun Hong Hui's ongoing PhD research).…”

Section: Part III Novel Approaches To Account For Heterogeneities Anmentioning

confidence: 94%

See 1 more Smart Citation

Advanced Techniques for Reservoir Simulation and Modeling of Nonconventional Wells

Durlofsky¹,

Aziz²

2004

View full text Add to dashboard Cite

Section: Part III Novel Approaches To Account For Heterogeneities Anmentioning

confidence: 94%

“…The total drainage area is 328 ft × 328 ft. Detailed simulation properties are given in Lee et al (2003). We simulate two coarse grid models -one with the standard hole well model and one with the upscaled well model.…”

Section: Multiblock Cross Section Examplementioning

confidence: 99%

Advanced Techniques for Reservoir Simulation and Modeling of Nonconventional Wells

Durlofsky¹,

Aziz²

2004

View full text Add to dashboard Cite

“…Hexahedral multiblock grids have shown good promise for accurate reservoir simulations (Arbogast et al 2000;Jenny et al 2002;Lee et al 2002aLee et al , 2003. Unfortunately, the generation of the multiblock structure for complex reservoir geometries requires significant user expertise and has proved challenging to automate.…”

Section: Introductionmentioning

confidence: 99%

Unstructured Cut-Cell Grids for Modeling Complex Reservoirs

et al. 2014

View full text Add to dashboard Cite

Effective workflows for translating Earth models into simulation models require grids that preserve geologic accuracy, offer flexible resolution control, integrate tightly with upscaling, and can be generated easily. Corner-point grids and pillar-based unstructured grids fail to satisfy these objectives; hence, a truly 3D unstructured approach is required. This paper describes unstructured cutcell gridding tools that address these needs and improve the integration of our overall reservoir-modeling workflows.The construction of simulation grids begins with the geologic model: a numerical representation of the reservoir structure, stratigraphy, and properties. Our gridding uses a geochronological (GeoChron) map from physical coordinates to an unfaulted and unfolded depositional coordinate system. The mapping is represented implicitly on a tetrahedral mesh that conforms to faults, and it facilitates accurate geostatistical modeling of static depositional properties. In the simplest use case, we create an explicit representation of the geologic model as an unstructured polyhedral grid. Away from faults and other discontinuities, the cells are hexahedral, highly orthogonal, and arranged in a structured manner. Geometric cutting operations create general polyhedra adjacent to faults and explicit contact polygons across faults. The conversion of implicit models to explicit grids is conceptually straightforward, but the implementation is nontrivial because of the limitations of finite precision arithmetic and the need to remove small cells formed in the cutting process.In practice, simulation grids are often constructed at coarser resolutions than Earth models. Our implementation of local grid coarsening and refinement exploits the flexibility of unstructured grids to minimize upscaling errors and to preserve critical geologic features. Because the simulation grid and the geologic model are constructed by use of the same mapping, fine cells can be nested exactly inside coarse cells. Therefore, flow-based upscaling can be applied efficiently without resampling onto temporary local grids. This paper describes algorithms and data structures for constructing, storing, and simulating cut-cell grids. Examples illustrate the accurate modeling of normal faults, y-faults, overturned layers, and complex stratigraphy. Flow results, including a fieldsector model, show the suitability of cut-cell grids for simulation.

show abstract

“…The latter is what we are interested in. There have been studies of the nonorthogonality error in the literature (Edwards 2000;Lee et al 2003), focusing on the corner-point grids that exhibit strong areal nonorthogonality. Moreover, those studies are mostly numerical and do not provide systematic analytical characterizations of the nonorthogonality errors.…”

Section: Introductionmentioning

confidence: 99%

“…However, the effect can be strong near pinchouts and if the dip angle is large. [See Lee et al (2003) for numerical examples. ]…”

Section: Introductionmentioning

confidence: 99%

Effect of Grid Deviation on Flow Solutions

Parashkevov

2009

SPE Journal

View full text Add to dashboard Cite

The two-point flux finite-volume method (2P-FVM) is the most widely used method for solving the flow equation in reservoir simulations. For 2P-FVM to be consistent, the simulation grid needs to be orthogonal (or k-orthogonal if the permeability field is anisotropic). It is well known that corner-point grids can introduce large errors in the flow solutions because of the lack of orthogonality in general. Multipoint flux formulations that do not rely on grid orthogonality have been proposed, but these methods add significant computational cost to solving the flow equation.Recently, 2.5D unstructured grids that combine 2D Voronoi areal grids with vertical projections along deviated coordinate lines have become an attractive alternative to corner-point gridding. The Voronoi grid helps maintain orthogonality areally and can mitigate grid orientation effects. However, experience with these grids is limited.In this paper, we present an analytical and numerical study of these 2.5D unstructured grids. We focus on the effect of grid deviation on flow solutions in homogeneous, but anisotropic, permeability fields. In particular, we consider the grid deviation that results from gridding to sloping faults. We show that 2P-FVM does not converge to the correct solution as the grid refines. We further quantify the errors for some simple flow scenarios using a technique that combines numerical analysis and asymptotic expansions. Analytical error estimates are obtained. We find that the errors are highly flow dependent and that they can be global with no strong correlation with local nonorthogonality measures. Numerical tests are presented to confirm the analytical findings and to show the applicability of our conclusions to more-general flow scenarios.

show abstract

New Developments in Multiblock Reservoir Simulation: Black Oil Modeling, Nonmatching Subdomains and Near-Well Upscaling

Cited by 11 publications

References 17 publications

Advanced Techniques for Reservoir Simulation and Modeling of Nonconventional Wells

Advanced Techniques for Reservoir Simulation and Modeling of Nonconventional Wells

Unstructured Cut-Cell Grids for Modeling Complex Reservoirs

Effect of Grid Deviation on Flow Solutions

Contact Info

Product

Resources

About