A model itself is either physical for example, a laboratory sandpack or mathematical. Reservoir modeling for simulation purposes aapg wiki. Introduction the grid orientation effect is an anomalous dependence of a numerical solution on the computational grid employed for the discretization of the problem spatial domain. A controlvolume, finiteelement method for local mesh refinement in thermal reservoir simulation. The simulation model itself can be a useful tool in allocating effort and expense in determination of reservoir fluid and rock data. In basin modelling, lgr has not yet been implemented. It results that the time step is globally constrained both by the nearwell small refined cells and by the high darcy velocities and high non. Netbased desktop application that integrates modification, simulation and visualization of a black oil model of hydrocarbon reservoir using finite difference fully implicit and impes formulations as formulated by turgay ertekin, j. The layering in reservoir simulation grids is often based on the geology, e. Automatic grid setting may be modified for specific studies such as coning. It can be simply considered as the process of mimicking the behavior of fluid flow in a.
Reservoir simulation tasks gather and input the rock and fluids data reservoir description choose certain numerical features of the grid number of cells, cells. Jacobs koninklijkelshell exploratie en produktie laboratorium, rijswijk, the netherlands received may 9, 1986. The validation tests show that the approach presented is capable of providing accurate production predictions without the well structure limitation and with shorter simulation times as demanded by the application of a full fine grid refinement. Property upscaling from grids of different sizes 3. Natural fractured reservoir engineering phdg textbooks in preparation, intended to be issued during 2015. The block system initially a twodimensional cartesian coordinate system with axes i2 and i3 is selected for the representation of a block system for reservoir simulation. Computer runs may be performed at an early stage of the reservoir study to estimate sensitivity of calculated reservoir performance to variations in the various required input data.
If local grid refinement lgr is commonly used in reservoir simulations in the nearwell regions, current commercial simulators still make use of a single time stepping on the whole reservoir domain. Shale gas and tight oil reservoir simulation delivers the latest research and applications used to better manage and interpret simulating production from shale gas and tight oil reservoirs. Reservoir simulation process reservoir simulation is briefly. In this paper we investigate the alternative of using horizontal layers, where the link to the geology model is by the representation of the petrophysics alone. In the shallow water example, the grid might in general be spaced every few feetbut it could be adaptively refined to have grid points every few inches in places where there are large waves. Simulation studies see conducting a reservoir simulation study. Mathematics and computers in simulation, elsevier, 2014, volume 118, pp. This idea was put forward by li, cullick, and lake 7. When this is done in conventional simulators, unnecessary refinement occurs in some regions. Since the trailing part of the geometry is complex it is difficult to create such a region that closely follows the geometry outside the boundary layer. Efficient use of domain decomposition and local grid. Simulation study of co 2 eor in tight oil reservoirs with. Pdf flow simulation using local grid refinements to model. The obvious drawback is the failure to honor the structure in the grid geometry.
Adaptive local grid refinement and multigrid in numerical. Therefore local grid refinement capabilities are becoming more important in reservoir simulation as the enhanced recovery procedures being used become more complex with more localized phenomena. Industry standard oil reservoir simulators can handle local re. Calculating well deliverability in gas condensate reservoirs. The approach of local grid refinement is used to model biwing hydraulic fractures or orthogonal fracture networks. The paper compares simulation results using the pseudopressure method and fine scale simulation. Local grid refinement cfd online discussion forums. Because of the recent development in reservoir modelling and computers processing power, reservoir simulation is being used at all stages of reservoir management mustafiz and islam 2008. Adaptive refinement of grid in this example, we show how to make grids that dynamically adapt to an advancing saturation front. The unstructured voronoi numerical model is common to saphir, topaze and rubis, only the local grid refinement around the wells will be different. A schematic diagram of this process is shown in figure 1. A musthave handbook for anyone involved in reservoir simulation, reservoir simulation will help the reader decide when and how to use simulation for forecasting performance.
The observed pressure and produced volumes of the two phases are matched with the simulated data to obtain. The reservoir characterization required to define porosity and permeability for each grid block in a reservoir simulation model is more stringent and at the same time more loosely defined than reservoir characterization required in detailed development geology studies. Local grid refinement, it is a widely used expression for the process of dividing one or several grids in the reservoir model into smaller sized grids allowing enhanced grid definition, which is useful for modeling wells or hydraulic fractures and other complex reservoir structures. Reservoir simulation handson tutorials cmgpackage software installations on participants computers introduction to cmgsoftware suit. Reservoir simulation, grid orientation effect, interpolation schemes, finite volume method. On the other hand, a horizontal grid will honor the.
Pdf flow simulation using local grid refinements to. Mathematical model computer codes numerical model physical model figure 1. Sep 15, 2016 the recent development of tight oil reservoirs has led to an increase in oil production in the past several years due to the progress in horizontal drilling and hydraulic fracturing. It is best to use the simplest model which can meet the study objectives. Simulation of petroleum reservoir performance refers to the construction and operation of a model whose behavior assumes the appearance of actual reservoir behavior. Lgr stands for local grid refinement reservoir engineering. However, most papers on the subject published since mrosovsky et al 1973 focus on enhanced accuracy near wells. Local grid refinement is used to simulate flow in grid elements intersected by fractures. Discretization and gridding in reservoir simulation 2. Heinemann et al 1983 discuss dynamic grid refinement to improve the resolution at flood fronts. It is used to add detail where justified by data availability and to keep a coarse resolution where less data are available. If the reservoir is small and vertical and areal effects are important, it may be possible to use a fullfield 3d model. Using local grid refinement in a multipleapplication.
The local grid refinement lgr option allows enhanced grid definition in areas needing a higher level of simulation accuracy, such as near wells or in areas of complex geology. On the factors influencing the grid orientation effect in. The grid forms automatically and with the minimum number of cells for faster simulations. Reservoir fluid characterisation supplementary scripts used at the montanuniversitat up to the retirement. The findings from this stage are used as a guide for further grid refinement. Nearwell local space and time refinement in reservoir simulation. 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. Nearwell local space and time refinement in reservoir simulation walid kheriji, roland masson, arthur moncorge to cite this version. How is local grid refinement reservoir engineering abbreviated. 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. The quantities are gathered in such a manner that the first group contains only constant properties of the block.
Modflowlgr allows smaller parts of a larger model domain to be refined without refining the entire model. A simulation engineer can spend countless hours defining the reservoir model. Adaptive mesh refinement amr changes the spacing of grid points, to change how accurately the solution is known in that region. Pdf mathematical models for oil reservoir simulation. Journal of computational physics 77, 140165 1988 adaptive local grid refinement and multi grid in numerical reservoir simulation g. Output to other industry formats eclipse, resqml, etc 4. To this end, we consider a quarter fivespot with heterogeneity sampled from on layer of the spe10 data set. Horizontal simulation grids as alternative to structurebased. The inserted grid may be cartesian center or radial upper left. The majority of reservoir simulation studies conducted today use cartesian or cornerpoint structured grids with some application of local grid refinement to evaluate infill well locations or to more accurately calculate water andor gas coning in a well. Simulation grid generation stair step, truncated, pebi unstructured local grid refinement lgr can be applied 2. A version of modflow, called modflowlgr for local grid refinement was developed mehl and hill, 2005 to support the use of locally refined grids to simulate groundwater flow. As a fullfeatured threephase, fourcomponent black oil simulator, imex also includes local grid refinement lgr, comprehensive. Reservoir modeling and simulation cairo university.
Local grid refinement is a technique which aims to provide improved accuracy in subregions of a reservoir simulation study. A common requirement in reservoir simulation is an increased level of detail around an item of interest such as a well. Reservoir simulation ertekinabbaszadeh ips2014 v2 ma. Modeling hydraulic fractures in finite difference simulators. Imex models complex, heterogeneous, faulted oil and gas reservoirs, using millions of grid blocks, to achieve the most reliable predictions and forecasts. Lgr is defined as local grid refinement reservoir engineering somewhat frequently.
On the forum i found that local refinement is usually done by creating a separate region with a denser grid. One could therefore create a grid that aligns well with geological structures by putting grid cell boundaries at highcontrastsurfaces. The first stage constructs computational meshes based on reasonable estimates of cell size and grid stretching ratios and investigates the sensitivity of the computed flow field to these parameters. Outcrop characterization of deepwater channels from the tres pasos formation of the magallanes basin in chile provided the framework. Grid coarsening may be used to amalgamate cells in regions of the reservoir which are less important to speed up simulation run times. The recent development of tight oil reservoirs has led to an increase in oil production in the past several years due to the progress in horizontal drilling and hydraulic fracturing. Optimal gridding selection for fieldscale reservoir. 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. Local grid refinement lgr is applied in reservoir simulation routinely for structured and unstructured grids and implemented in commercial simulators.
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