Unstructured gridding has become an important subject matter in reservoir simulation. The matlab reservoir simulation toolbox mrst sintef. A method, apparatus, and program product utilize a generalized grid cell pinchout operation to remove small cells from a reservoir simulation grid, e. Globally structured grids, including the socalled stratigraphic or cpg corner point.
Sepehrnoori1 1center for petroleum and geosystems engineering, the university of texas at austin, usa. For reservoir simulation using the blackoil model on unstructured grids, only the fully implicit solution method has been used for solving the governing equations of this. An advanced grid system design was developed to capture accurately the effects of geometrically complex features such as geological features faults, pinch outs and inclined beddings and wellrelated phenomenon multilateral wells of general orientation in triangular coordinates. Cell indices and coordinate indices in a structured grid 23. Unstructured coarse grid generation for reservoir flow simulation using background grid approach conference paper pdf available january 2009 with 105 reads how we measure reads. Using unstructured grids for modeling complex discrete fracture. The structure of unstructured grids centre for computational. Highquality grids guarantee the fidelity of a reservoir model and keep the flow calculations simple. Detailed nearwell modeling and upscaling in condensate. Request pdf distributed unstructured grid infrastructure for complex reservoir simulation it is now standard practice to use reservoir simulation as an everyday tool for better engineering and. The use of numerical simulation to optimize reservoir performance in unconventional liquid reservoirs ulr continues to be an important topic in the industry.
Pdf unstructured gridding and consistent discretizations for. Reservoir evaluation can be broken into two main categories. The natural state model of the field is obtained by running the simulation for a long time until the reservoir parameters are reached to stabilized conditions. This work presents the implementation of an ebfvm formulation using unstructured grids for tridimensional compositional reservoir simulation in conjunction with an impec approach. The definition of position and shape of subdomain boundaries is an open. Basics of reservoir simulation with the eclipse reservoir. Figure 2 voronoi grid closeup on hydraulic fractures as a starting point, let us further assume that the gas pvt has constant viscosity and. For this aspect of the problem, we generalize streamline simulation techniques to unstructured grids. The nextgeneration reservoir simulators will be unstructured.
Distributed unstructured grid infrastructure for complex. Pdf this paper presents a 2d implementation of an elementbased finite volume formulation ebfvm using triangles, quadrilaterals, or a. Grid as in figure 33, but with fault 106 figure 36. Eos2 fluid property module of tough2 simulation codes is used for the numerical simulation of the geothermal model. Alternatively, a full 3d unstructured grid may be defined. The use of structured grids in reservoir simulation is very. With time, growing interest in surface and groundwater interactions, local refinement with nested and unstructured grids, karst groundwater flow, solute transport, and saltwater intrusion. The generation of accurate and reliable unstructured 3d models for reservoir simulation remains a challenge. Modeling these effects can have significant impact on the accuracy of the simulation and prediction of reservoir. Grid generation is critical to numerical reservoir simulations. Pdf a tvd scheme for 3d unstructured grids applied to. 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.
Grid design and numerical modeling of multiphase flow in. Reservoir simulation provides a practical approach to characterize key reservoir parameters in this process such as temperature. Structured versus unstructured pebi grids in reservoir. Pebigrids used for reservoir simulations are discussed by verma and. Application of fluxcorrected transport to an unstructured. Unstructuredcoarsegrid generation using backgroundgrid. Coupled hydromechanical simulation of multiphase fluid. Geometry modeling grid generation stanford university. By doing such thing, the cells of the reservoir are modi.
Generalized traveltime inversion on unstructured grids. Transmissibility corrections and grid control for shale. Application of fluxcorrected transport to an unstructuredgrid finitevolume form ulation for reservoi r simulation conference paper pdf available june 2007 with 67 reads how we measure reads. Ebfvm, chemical compositional model, unstructured grid, petroleum reservoir simulation. Previously, an unstructured grid reservoir simulation workflow is introduced ding et al. Transmissibility corrections and grid control for shale gas numerical simulation p 323 figure 1 voronoi grid for the reservoir described in table 1. Benefits of using unstructured grid are demonstrated on simulation example by using unstructured grid and being compared with the structured grid. Evazi, spe, sharif university of technology, and h. Tracing streamlines on unstructured grids from finite volume discretizations s. This presented work introduces an enhanced way of complex fracture modeling in unconventional reservoir simulation by using unstructured. The use unstructured meshes in reservoir simulation date from the 1980 decade. For over 30 years, the modflow program has been widely used by academics, private consultants, and government scientists to accurately, reliably, and efficiently simulate groundwater flow. In this paper two automated and robust algorithms for generation of unstructured grids suitable for multiscale finite volume method in oil reservoirs are presented.
Transmissibility upscaling on unstructured grids for highly. Geometry approaches, are widely used in the reservoir simulation. 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. Rozon 1989 used the cvfem control volume finite element method, developed originally by. One major component of the workflow is the nearwell unstructured grid modeling framework which consists of a 2. 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. Though this concept was introduced to the petroleum industry as. Calculation of permeability tensors for unstructured grid blocks r. The simulation results can be saved as e100 binaries to link the simulator with the software in your workflow.
We first present the basic issues and workflow for reservoir simulation with unstructured grids. Geostatistical models of reservoir properties can be hundreds of millions of cells. An embedded 3d fracture modeling approach for simulating. Basic geological modeling features handling of well log data. Tracing streamlines on unstructured grids from finite. An unstructured grid may be defined in two dimensions, and then applied to each layer of a reservoir model, so that a typical cell is a hexagonal prism. Unstructured coarse grid generation for reservoir flow simulation using background grid approach. The book also teaches grid coarsening, upscaling, and flow diagnostics. Juanes, spe, massachusetts institute of technology, h.
Introduction to reservoir simulation as practiced in industry. Use next generation simulators that honors geology with unstructured grids. A tvd scheme for 3d unstructured grids applied to compositional reservoir simulation article pdf available in brazilian journal of chemical engineering 344. This paper describes a practical method in which irregular or locally irregular grids are used in reservoir simulation with the advantages of flexible approximation of reservoir geometry and. 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. In combination, these techniques provide a prototype workflow for the construction of unstructured simulation models. Hybrid mesh generation for reservoir flow simulation in. Advanced discretization methods for flow simulation using.
Calculation of permeability tensors for unstructured grid. Stanfords general purpose research simulator gprs serves as the base for the new framework. The development of a generalpurpose reservoir simulation framework for coupled systems of unstructured reservoir models and advanced wells is the subject of this dissertation. Using unstructured grids for modeling complex discrete. Pdf this paper presents a 2d implementation of an elementbased finitevolume formulation ebfvm using triangles, quadrilaterals, or a. The multiscale finite volume method is an efficient numerical method for flow simulation in porous media. A popular unstructured grid is the perpendicular bisector pebi grid.
University of alberta reservoir geomechanics research group rg2 energi simulation industrial research consortia in reservoir geomechanics for unconventional resources coupled hydromechanical simulation of multiphase fluid flow in fractured shale reservoirs using distinct. Computational fluid dynamics in hydraulic and sedimentation engineering by nils reidar b. The generalized grid cell pinchout operation may utilize a connectivity matrix representing transmissibilities of one or more pinch cells to be removed as well as that of background cells. In this paper, new developments for grid generation, upscaling and streamline simulation for such models are described. The grid lines are curved to fit the shape of the boundaries unstructured grids. Unstructured grid model of naturally fractured reservoir sun and schechter. Transfinite interpolation, morphing, pde based, etc. Techniques for modeling complex reservoirs and advanced.
The multiscale finite volume method has been extensively studied on structured grids. In this paper, we discuss how to extend the gtt inversion method to fully unstructured grids in two and three spatial dimensions. In this thesis, unstructured grid models, which include high resolution in the well and nearwell region, are constructed and used to simulate condensate systems. Application of fluxcorrected transport to an unstructuredgrid finitevolume formulation for reservoir simulation fernando s. Basics of reservoir simulation with the eclipse reservoir simulator. Hybrid mesh generation for reservoir flow simulation in cpg grids 419 cpg grid, the cell faces are aligned with the geological structures of the real reservoir. Application of parallel computing techniques to a largescale reservoir simulation keni zhang, yushu wu, chris ding, and karsten pruess. However, the inversion method can be implemented on top of any simulator on a cartesian grid that outputs velocity. Abstract in the last decade, unstructured grids have been a very important step in the development of petroleum reservoir simulators. 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.
Unstructured cutcell grids for modeling complex reservoirs. This technique is defined by the storage of all physical properties at the. Complex, unstructured grids with many obscure challenges. Reservoir simulation is an area of reservoir engineering that, combining physics, mathematics, and computer programming to a reservoir model allows the analysis and the prediction of the fluid behavior in the reservoir over time it can be simply considered as the process of mimicking the behavior of fluid flow in a. Pdf unstructured coarse grid generation for reservoir. Automated workflow for unstructured grid reservoir simulation.
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