Reservoir Modelling Using Parametric Surfaces and Dynamically Adaptive Fully Unstructured Grids

Melnikova, Y.; Jacquemyn, Carl; Osman, H.; Salinas, P.; Gorman, Gerard J.; Hampson, Gary J.; Jackson, Matthew D.

doi:10.3997/2214-4609.201601887

Cited by 8 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our approach exploits the parametric representation of geometry that is inherent in CAD systems. This exports surfaces in a standard, CAD-compatible format (.STEP) and employs the functionality of CAD engines to assemble the model, either automatically or manually (Melnikova et al 2016). Alternatively, the NURBS surfaces can also be discretised and exported as triangulated surfaces (e.g.…”

Section: Model Constructionmentioning

confidence: 99%

“…Model assembly consists of three steps that are applied sequentially: (I) surface interactions (joining, terminating and stacking surfaces) follow rules based on the logic of superposition and cross-cutting relationships that arise from rock-forming processes (Jackson et al 2015); (II) wells are merged with "watertight" volumes bounded by surfaces; and (III) "watertight" volumes are meshed (Melnikova et al 2016). Each surface is assigned metadata that define its hierarchical level, relationship with other volumes and surfaces, such as removing older surfaces or being removed by younger surfaces, and the rock properties within the volumes it bounds.…”

Section: Model Constructionmentioning

confidence: 99%

“…Each surface is assigned metadata that define its hierarchical level, relationship with other volumes and surfaces, such as removing older surfaces or being removed by younger surfaces, and the rock properties within the volumes it bounds. During model assembly, all geometrical modifications are performed through Boolean operations (intersection, subtraction, union) (Melnikova et al 2016). Once all geometrical modifications have been completed, the model is meshed when required for numerical analysis (e.g.…”

Section: Model Constructionmentioning

confidence: 99%

“…NURBS-surface-based models can be exported in different formats, depending on the workflow design. Our workflow uses an unstructured tetrahedral mesh to preserve the geometry of the modelled surfaces (Melnikova et al 2016), which can be used directly, without upscaling, for flow simulation using a next-generation, adaptivemesh simulator (e.g. IC-FERST; Jackson et al 2015;Salinas et al 2017) or to conduct flow diagnostics (Zhang et al 2017).…”

Section: Compatibility With Conventional and Next-generation Reservoimentioning

confidence: 99%

See 3 more Smart Citations

Surface-Based Geological Reservoir Modelling Using Grid-Free NURBS Curves and Surfaces

2018

View full text Add to dashboard Cite

Building geometrically realistic representations of geological heterogeneity in reservoir models is a challenging task that is limited by the inflexibility of pre-defined pillar or cornerpoint grids. The surface-based modelling workflow uses grid-free surfaces that allows efficient creation of geological models without the limitations of pre-defined grids. Surface-based reservoir modelling uses a boundary representation approach in which all heterogeneity of interest (structural, stratigraphic, sedimentological, diagenetic) is modelled by its bounding surfaces, independent of any grid. Volumes bounded by these surfaces are internally homogeneous and, thus, no additional facies or petrophysical modelling is performed within these geological domains and no grid or mesh discretisation is needed during modelling. Any heterogeneity to be modelled within such volumes is incorporated by adding surfaces. Surfaces and curves are modelled using a parametric non-uniform rational B-splines (NURBS) description. These surfaces are efficient to generate and manipulate, and allow fast creation of multiple realisations of geometrically realistic reservoir models. Multiple levels of surface hierarchy are introduced to allow modelling of all features of interest at the required level of detail; surfaces at one hierarchical level are constructed so as to truncate or conform to surfaces of a higher hierarchical level. This procedure requires the joining, terminating and stacking of surfaces to ensure that models contain "watertight" surface-bounded volumes. NURBS curves are used to represent well trajectories accurately, including multi-laterals or sidetracks. Once all surfaces and wells have been generated, they are combined into a reservoir model that takes into account geological relationships between surfaces and preserves realistic geometries.

show abstract

Section: Model Constructionmentioning

confidence: 99%

Section: Model Constructionmentioning

confidence: 99%

Section: Model Constructionmentioning

confidence: 99%

Section: Compatibility With Conventional and Next-generation Reservoimentioning

confidence: 99%

See 2 more Smart Citations

Surface-Based Geological Reservoir Modelling Using Grid-Free NURBS Curves and Surfaces

2018

View full text Add to dashboard Cite

show abstract

“…Its robustness is then demonstrated using example models containing complex geometries with very large aspect ratio domains and large permeability contrasts, discretised using highly distorted triangular and tetrahedral meshes. The example models represent various complex geological reservoirs and were constructed using a surface‐based approach in which heterogeneous domains are represented as volumes bounded by surfaces . However, the new formulation is not restricted to geological problems.…”

Section: Introductionmentioning

confidence: 99%

Improving the robustness of the control volume finite element method with application to multiphase porous media flow

Salinas

Pavlidis

Xie

et al. 2017

Numerical Methods in Fluids

View full text Add to dashboard Cite

SummaryControl volume finite element methods (CVFEMs) have been proposed to simulate flow in heterogeneous porous media because they are better able to capture complex geometries using unstructured meshes. However, producing good quality meshes in such models is nontrivial and may sometimes be impossible, especially when all or parts of the domains have very large aspect ratio. A novel CVFEM is proposed here that uses a control volume representation for pressure and yields significant improvements in the quality of the pressure matrix. The method is initially evaluated and then applied to a series of test cases using unstructured (triangular/tetrahedral) meshes, and numerical results are in good agreement with semianalytically obtained solutions. The convergence of the pressure matrix is then studied using complex, heterogeneous example problems. The results demonstrate that the new formulation yields a pressure matrix than can be solved efficiently even on highly distorted, tetrahedral meshes in models of heterogeneous porous media with large permeability contrasts. The new approach allows effective application of CVFEM in such models.

show abstract

Vanishing artificial diffusion as a mechanism to accelerate convergence for multiphase porous media flow

Salinas

Pain

Osman

et al. 2020

Computer Methods in Applied Mechanics and Engineering

Self Cite

View full text Add to dashboard Cite

Numerical solution of the equations governing multiphase porous media flow is challenging. A common approach to improve the performance of iterative non-linear solvers for these problems is to introduce artificial diffusion. Here, we present a mass conservative artificial diffusion that accelerates the non-linear solver but vanishes when the solution is converged. The vanishing artificial diffusion term is saturation dependent and is larger in regions of the solution domain where there are steep saturation gradients. The non-linear solver converges more slowly in these regions because of the highly non-linear nature of the solution. The new method provides accurate results while significantly reducing the number of iterations required by the non-linear solver. It is particularly valuable in reducing the computational cost of highly challenging numerical simulations, such as those where physical capillary pressure effects are dominant. Moreover, the method allows converged solutions to be obtained for Courant numbers that are at least two orders of magnitude larger than would otherwise be possible.

show abstract

Reservoir Modelling Using Parametric Surfaces and Dynamically Adaptive Fully Unstructured Grids

Cited by 8 publications

References 0 publications

Surface-Based Geological Reservoir Modelling Using Grid-Free NURBS Curves and Surfaces

Surface-Based Geological Reservoir Modelling Using Grid-Free NURBS Curves and Surfaces

Improving the robustness of the control volume finite element method with application to multiphase porous media flow

Vanishing artificial diffusion as a mechanism to accelerate convergence for multiphase porous media flow

Contact Info

Product

Resources

About