Unstructured Coarse Grid Generation for Reservoir Flow Simulation Using Background Grid Approach

2009 ◽  
Author(s):  
Mohammad Evazi ◽  
Hassan Mahani
Keyword(s):  
Flow Simulation ◽  
Grid Generation ◽  
Coarse Grid ◽  
Reservoir Flow ◽  
Grid Approach ◽  
Background Grid

Unstructured-Coarse-Grid Generation Using Background-Grid Approach

SPE Journal ◽  
2010 ◽  
Vol 15 (02) ◽  
pp. 326-340 ◽  
Author(s):  
M.. Evazi ◽  
H.. Mahani
Keyword(s):  
Source Term ◽  
Local Density ◽  
Fluid Velocity ◽  
Flow Simulation ◽  
Grid Generation ◽  
Coarse Grid ◽  
Optimization Techniques ◽  
Fine Grid ◽  
Background Grid ◽  
Coarse Grids

Summary Reservoir flow simulation involves subdivision of the physical domain into a number of gridblocks. This is best accomplished with optimized gridpoint density and a minimized number of gridblocks, especially for coarse-grid generation from a fine-grid geological model. In any coarse-grid generation, proper distribution of gridpoints, which form the basis of numerical gridblocks, is a challenging task. We show that this can be achieved effectively by a novel grid-generation approach based on a background grid that stores gridpoint spacing parameters. Spacing parameter (L) can be described by Poisson's equation (∇2L = G), where the local density of gridpoints is controlled by a variable source term (G); see Eq. 1. This source term can be based on different gridpoint density indicators, such as permeability variations, fluid velocity, or their combination (e.g., vorticity) where they can be extracted from the reference fine grid. Once a background grid is generated, advancing-front triangulation (AFT) and then Delaunay tessellation are invoked to form the final (coarse) gridblocks. The algorithm produces grids varying smoothly from high- to low-density gridpoints, thus minimizing use of grid-smoothing and -optimization techniques. This algorithm is quite flexible, allowing choice of the gridding indicator, hence providing the possibility of comparing the grids generated with different indicators and selecting the best. In this paper, the capabilities of approach in generation of unstructured coarse grids from fine geological models are illustrated using 2D highly heterogeneous test cases. Flexibility of algorithm to gridding indicator is demonstrated using vorticity, permeability variation, and velocity. Quality of the coarse grids is evaluated by comparing their two-phase-flow simulation results to those of fine grid and uniform coarse grid. Results demonstrate the robustness and attractiveness of the approach, as well as relative quality/performance of grids generated by using different indicators.

scholarly journals Flow Simulation Using Local Grid Refinements to Model Laminated Reservoirs

2018 ◽  
Vol 73 ◽  
pp. 5 ◽  
Author(s):  
Manuel Gomes Correia ◽  
Célio Maschio ◽  
Denis José Schiozer
Keyword(s):  
Simulation Model ◽  
Dynamic Properties ◽  
Flow Behavior ◽  
Flow Simulation ◽  
Coarse Grid ◽  
Thin Layers ◽  
Static Properties ◽  
Dynamic Representation ◽  
Medium Flow ◽  
Local Grid

Super-giant carbonate fields, such as Ghawar, in Saudi Arabia, and Lula, at the Brazilian pre-salt, show highly heterogeneous behavior that is linked to high permeability intervals in thin layers. This article applies Local Grid Refinements (LGR) integrated with upscaling procedures to improve the representation of highly laminated reservoirs in flow simulation by preserving the static properties and dynamic trends from geological model. This work was developed in five main steps: (1) define a conventional coarse grid, (2) define LGR in the conventional coarse grid according to super-k and well locations, (3) apply an upscaling procedure for all scenarios, (4) define LGR directly in the simulation model, without integrate geological trends in LGR and (5) compare the dynamic response for all cases. To check results and compare upscaling matches, was used the benchmark model UNISIM-II-R, a refined model based on a combination of Brazilian Pre-salt and Ghawar field information. The main results show that the upscaling of geological models for coarse grid with LGR in highly permeable thin layers provides a close dynamic representation of geological characterization compared to conventional coarse grid and LGR only near-wells. Pseudo-relative permeability curves should be considered for (a) conventional coarse grid or (b) LGR scenarios under dual-medium flow simulations as the upscaling of discrete fracture networks and dual-medium flow models presents several limitations. The conventional approach of LGR directly in simulation model, presents worse results than LGR integrated with upscaling procedures as the extrapolation of dynamic properties to the coarse block mismatch the dynamic behavior from geological characterization. This work suggests further improvements for results for upscaling procedures that mask the flow behavior in highly laminated reservoirs.

A coarse-grid approach to representing building blockage effects in 2D urban flood modelling

2012 ◽  
Vol 426-427 ◽  
pp. 1-16 ◽  
Author(s):  
Albert S. Chen ◽  
Barry Evans ◽  
Slobodan Djordjević ◽  
Dragan A. Savić
Keyword(s):  
Coarse Grid ◽  
Urban Flood ◽  
Flood Modelling ◽  
Grid Approach ◽  
Urban Flood Modelling

Multiscale Integration for Karst-Reservoir Flow-Simulation Models

2020 ◽  
Vol 23 (02) ◽  
pp. 518-533
Author(s):  
Manuel Gomes Correia ◽  
João Carlos von Hohendorff Filho ◽  
Denis José Schiozer
Keyword(s):  
Flow Simulation ◽  
Simulation Models ◽  
Reservoir Flow ◽  
Karst Reservoir

scholarly journals High-resolution subgrid models: background, grid generation, and implementation

2014 ◽  
Vol 64 (4) ◽  
pp. 519-535 ◽  
Author(s):  
Aissa Sehili ◽  
Günther Lang ◽  
Christoph Lippert
Keyword(s):  
High Resolution ◽  
Grid Generation ◽  
Background Grid

Coupled Reservoir Flow Simulation: Fault Leakage Analysis

2009 ◽  
Author(s):  
Luis Glauber Rodrigues ◽  
Luciane Bonet Cunha ◽  
Richard J. Chalaturnyk
Keyword(s):  
Flow Simulation ◽  
Reservoir Flow ◽  
Fault Leakage
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