A streamline simulation technique for the efficient modeling of flow and transport on unstructured grids is presented. The book also teaches grid coarsening, upscaling, and flow diagnostics. A 3d surface of an area of the fullfield unstructured grid simulation showing horizontal wells and faults. Rupperts algorithm is often used to convert an irregularly shaped polygon into an unstructured grid of triangles. Reservoir simulation is efficiently computed based on the drainage volume information from the unstructured grid system using fmm, and the simulation results are validated with finitedifference based and finitevolume based numerical results. Siam journal on scientific computing siam society for. Stanfords general purpose research simulator gprs serves as the base for the new framework. The topics of mesh generation and adaptation, spatial discretization, and solution techniques for steady flows are covered. Pdf unstructured gridding and consistent discretizations for. A method is disclosed, which is practiced by a reservoir simulator, for simulating a reservoir and generating a set of simulation results, the simulation results including a framework, the framework further including a plurality of grid cells, comprising. Us7933750b2 method for defining regions in reservoir.
Highquality grids guarantee the fidelity of a reservoir model and keep the flow calculations simple. Grid as in figure 33, but with fault 106 figure 36. Although vtk is a large and complex library, it is possible to write with it short and easily understandable applications, which perform. An unstructured grid version of modflow for simulating groundwater flow mcdonald, m. The structure of unstructured grids centre for computational. Mathematical model computer codes numerical model physical model figure 1.
The inverse of the matrix for the original unstructured grid. Discretization and gridding in reservoir simulation 2. This tool can be used to provide the flowbased assessment of the coarse model. Systems and methods for basin to reservoir modeling to identify any higrade drilling targets based on the linking of static and dynamic reservoir rock and fluid properties. Within the context of petroleum reservoir simulation, mpfa methods are commonly considered, as they are controlvolume based, locally conservative, introduce only one unknown per block, are applicable for multiphase flow problems, and allow the use of grids with general geometry. The grid generation by algebraic methods is based on mathematical interpolation function. Complex, unstructured grids with many obscure challenges. In addition to triangles and tetrahedra, other commonly used elements in finite element simulation include quadrilateral 4noded and hexahedral 8noded elements in 2d and 3d, respectively. A popular unstructured grid is the perpendicular bisector pebi grid. Though this concept was introduced to the petroleum industry as. This process is experimental and the keywords may be updated as the learning algorithm improves. Geoquest, schlumberger eclipse 200 reference manual multisegment wells. It is done by using known functions in one, two or three dimensions taking arbitrary shaped regions. The computational domain might not be rectangular, but for the sake of.
Techniques for modeling complex reservoirs and advanced. The convergence characteristic of fmm on unstructured grids is investigated. Unstructured grid simulation of hydromechanical effects in fractured reservoir during co2 sequestration ukccs community network early career researcher winter school 8th 11th february 2011 imperial college london robert annewandter ecosse phdcandidate prof sebastian geiger institute of petroleum engineering heriotwatt university prof ian main. The sequential method for the blackoil reservoir simulation on unstructu red grids q baoyan li, zhangxin chen, guanren huan.
Simulation of petroleum reservoir performance refers to the construction and operation of a model whose behavior assumes the appearance of actual reservoir behavior. Application of fluxcorrected transport to an unstructured. Determination of fracture scale limit in numerical simulations of. Pebigrids used for reservoir simulations are discussed by verma and.
Introduction webster defines simulate as to assume the appearance of without reality. Vtk is a software system for computer graphics, visualization and image processing. The finite volume grid is formed as the dual of the underlying tetrahedral in three dimensions or triangular in two dimensions primal grid. Modern reservoir simulation faces increasingly complex physical models and highly resolved, unstructured grids. Cell indices and coordinate indices in a structured grid 23.
Basics of reservoir simulation with the eclipse reservoir. Structured and unstructured grids for anisotropic, inhomogeneous media, proc. Unstructured gridding and consistent discretizations for reservoirs with faults and complex wells. Reservoir simulation process reservoir simulation is briefly. The task is to achieve profound understanding rather than to write a manual or a. Application of fluxcorrected transport to an unstructuredgrid finitevolume form ulation f or reservoir simulation fernando s. In fractured vuggy reservoirs, the fracture scales differ and the fracture distribution is uneven, so fractures with varying scales may require. In combination, these techniques provide a prototype workflow for the construction of unstructured simulation models.
Reservoir evaluation can be broken into two main categories. Development of advanced reservoir simulation techniques for. The sequential method for the blackoil reservoir simulation on unstructured grids. Incompressible solvers for singlephase flow chapter 5. Reservoir fluid characterisation supplementary scripts used at the montanuniversitat up to the retirement. A schematic diagram of this process is shown in figure 1. Geometry modeling grid generation stanford university.
Spe rss aim clees ganzer 20061204 tc clean fraunhofer scai. The prolongation operators are computed numerically by solving localized. Basics of reservoir simulation with the eclipse reservoir simulator. Accurate multigrid solution of the euler equations on. Saudi aramco journal of technology fall 2015 3 pass grid point generation. Ebfvm, chemical compositional model, unstructured grid, petroleum reservoir simulation. High resolution geostatistics on coarse unstructured flow. Pdf reservoir modeling for flow simulation using surfaces. The grid lines are curved to fit the shape of the boundaries unstructured grids.
An introduction to reservoir simulation using matlab sintef. The use of structured grids in reservoir simulation is very. Cvfa method can directly discretize an equation on an arbitrarily shaped grid and is especially suitable for the hybrid grid reservoir simulation, we apply this method to dealing with the discretization of the governing equations of the blackoil model and. A wide variety of multiscale methods have been proposed in the literature to reduce.
The development of a generalpurpose reservoir simulation framework for coupled systems of unstructured reservoir models and advanced wells is the subject of this dissertation. The adaptation of unstructured grids for transonic viscous flow simulation finite elements in analysis and design, vol. Unstructured grid cartesian grid reservoir simulation geostatistical method petrophysical property these keywords were added by machine and not by the authors. In this paper, new developments for grid generation, upscaling and streamline simulation for such models are described. The generation of accurate and reliable unstructured 3d models for reservoir simulation remains a challenge. Rapid simulation of naturally fractured unconventional. Introduction to reservoir simulation as practiced in industry. Geological survey techniques of waterresources investigations, book 6, chap. Sepehnoori 3d reservoir simulation using unstructured grid from figure 5, it is possible to verify that the saturation field at upper and lower surface of the reservoir obtained with both grid configurations are in good match. Techniques for modeling complex reservoirs and advanced wells.
Transfinite interpolation, morphing, pde based, etc. In this study, we propose a 3d unstructured grid, the generalized prism grid gpg, to model reservoirs with complicated geological geometries, including horizons, pinchouts, faults, fractures, and bore holes. The matlab reservoir simulation toolbox mrst sintef. The inserted grid may be cartesian center or radial upper left. Static, presentday, reservoir and field scale description grids or unstructured meshes are transformed into dynamic through time simulation grids or unstructured meshes that can subsequently be used for input to dynamic. The use unstructured meshes in reservoir simulation date from the 1980 decade.
Simple visualizations of unstructured grids with vtk. This work presents the implementation of an ebfvm formulation using unstructured grids for tridimensional compositional reservoir simulation in conjunction with an impec. An overview of the current state of the art in unstructured mesh techniques for computational fluid dynamics is given. Structured versus unstructured pebi grids in reservoir. Grid generation techniques structured grids ordered set of locally orthogonal lines several techniques can be used to map a computational domain into a physical domain.
An introduction to reservoir simulation using matlabgnu octave. This is frequently obtained in structured grids by local grid refinement, replacing a set of cells in the original grid by a finer grid fig. Pdf we present new approaches to reservoir modelling and flow. Because the connection between grid blocks is irregular for unstructured grids.
Discretization and gridding in reservoir simulation. This report shows examples of simple visualizations of unstructured grids with use of vtk the visualization toolkit. A common requirement in reservoir simulation is an increased level of detail around an item of interest such as a well. Structured versus unstructured pebi grids in reservoir modeling and simulation bogdan balan, schlumberger gss abstract application of unstructured irregular grids in reservoir simulation is one of the most important concepts that have been developed in the past decade 1. Simulation of petroleum reservoir performance refers to the construction and operation of a model whose behavior assumes the appearance of actual reservoir. The book then introduces unstructured grid generation by explaining the basics of delaunay triangulation and advancing front techniques. Remaining difficulties in these areas are highlighted, and directions for future work are outlined. The examples include the famous quarterfive spot problem, a cornerpoint grid with four intersecting faults, and a. Natural fractured reservoir engineering phdg textbooks in preparation, intended to be issued during 2015. Reservoir simulation is an area of reservoir engineering in which computer models are used to predict the flow of fluids typically, oil, water, and gas through porous media under the model in the broad scientific sense of the word, they understand a real or mentally created structure that reproduces or reflects the object being studied. Grid generation is critical to numerical reservoir simulations. Following an introduction of unstructured grid methods in reservoir simulation, this article discusses the gridding algo.
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