Extracting blocks for Simulation, from a GRDECL grid.
A procedure was designed to extract cubes for simulation from a reservoir represented by a GRDECL grid.
Category: Oil Industry Applications
Technologies: Simulation, Visualization, VTK.
This module was designed at the request of our customer for the software PetroSynapsis. This module is used to extract cubes for simulation from a reservoir represented by a GRDECL grid. The cube of simulation has the following characteristics:
Preselected number of cells Nx, Ny, Nz.
Location, size and orientation set by the user interactively.
The cube must display on their walls the reservoir properties.
Our response was to develope a widget as shown in the figure below (iBox1 on the right). The user can manipulate this widget, rotating and moving it in the 3D space, and also he can move any of its six faces with the help of six spherical handlers. Any of the reservoir properties can be visualized in the iBox1 while is moving. Another box called the iBox2 cube is an imaginary box whose dimensions are half of the box containing the reservoir.
There is a linear transform from the iBox2 to the IBox1, that can be represented by a 4×4 matrix. We apply the inverse of this transform to the unstructured GRDECL mesh, and the new mesh is sampled within the iBox2 space. This produces the image shown on iBox2 which is never shown to the user. This sampling produces Nx * Ny * Nz cells, with a higher resolution than the one displayed on iBox1. iBox2 together with the properties of their cells and the transform are stored in a proprietary format called “iBox” which was designed specifically for this project.
Now we apply the aforementioned transform to the iBox2, and the result is the iBox3 shown in the figure below on the right. There is much difference between the quality shown by iBox1 and iBox3. This is because iBox1 has the same resolution as the GRDECL mesh and iBox3 has a resolution preselected by the user. Another difference is that iBox1 shows the IJK orientation of the GRDECL mesh, and iBox3 shows the XYZ orientation of their own faces. iBox3 is the cube of simulation which is used as input to the simulator, in our case a 3D- combustion simulator. The output of the simulator produces spatiotemporal sequences of physical variables which are stored in the formats iBox or GRDECL, and then are displayed on PetroSynapsis in the original position of iBox1 or iBox3 (is the same position).
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Extracting blocks for Simulation, from a GRDECL grid. A proc...