Systems, methods, and computer-readable media for modeling complex wellbores in field-scale reservoir simulation

Abstract

Systems, methods, and computer-readable media are provided for a near-well unstructured grid model builder for generating a full-field unstructured grid for reservoir simulation. As described further below, the near-well unstructured grid model builder may include a workflow interface and a parallel unstructured grid model builder. The inputs to the near-well unstructured grid model builder may include existing well trajectory and completion data, future well data, a geological model, a structured grid simulation model, or any combination thereof. The near-well unstructured grid model builder may output a near-well unstructured grid having a specified grid resolution in regions of interest that include a well.

What is claimed is: 
     
         1 . A computer-implemented method for generating a near-well unstructured grid, the method comprising:
 receiving, by one or more processors, input data, the input data comprising:
 a structured geocellular model having a well or a structured reservoir simulation model having a well; and 
 well trajectory data and completion data for the well; 
   determining, by one or more processors, a field polygon based on the input data;   determining, by one or more processors, a reservoir polygon having a region of interest containing the well;   generating, by one or more processors, a plurality of grid points, the plurality of grid points comprising:
 a plurality of field grid points based on a user-specified field grid size; and 
 a plurality of reservoir grid points based on a user-specified reservoir grid size for each reservoir; 
 a plurality of well grid points based on a well grid size; and 
 a plurality of parallel near-wellbore grid points on both sides of each of the plurality of well grid points based on the well grid size; 
   performing conflicting point removal and point adjustments to generate a plurality of final grid points based on a point prioritization of weights assigned to the plurality of grid points;   performing, by one or more processors, a Delaunay triangulation based on the plurality of final grid points;   generating, by one or more processors, a Voronoi grid based on the Delaunay triangulation;   generating, by one or more processors, a near-well unstructured grid based on the Voronoi grid, the generating comprising:
 generating a geometry of the near-well unstructured grid; 
 generating properties of the near-well unstructured grid; and 
 generating perforation of the near-well unstructured grid; and 
   providing, by one or more processors, the near-well unstructured grid to a parallel reservoir simulator.   
     
     
         2 . The method of  claim 1 , comprising performing a reservoir simulation of the near-well unstructured grid via the parallel reservoir simulator. 
     
     
         3 . The method of  claim 1 , wherein the plurality of grid points comprises a plurality of region of interest grid points based on a user-specified region of interest grid size for the region of interest. 
     
     
         4 . The method of  claim 1 , wherein generating the plurality of grid points comprises a plurality of multi-level quad-tree local grid refinement (LGR) grid points based on a user-specified number of levels and user specified near-well distances. 
     
     
         5 . The method of  claim 1 , wherein generating the geometry of the near-well unstructured grid comprises generating a 2.5D unstructured grid geometry. 
     
     
         6 . The method of  claim 5 , wherein generating the geometry of the near-well unstructured grid comprises computing a depth to a bounding surface of each grid layer. 
     
     
         7 . The method of  claim 5 , wherein the generated unstructured grid geometry comprises a layer geometry of the structured geocellular model or a structured reservoir simulation model. 
     
     
         8 . The method of  claim 1 , wherein generating properties of the near-well unstructured grid comprising applying interpolation or point injection from a property value of the structured geocellular model or a structured reservoir simulation model to a grid point center of the near-well unstructured grid, such that the unstructured grid property maps closely match the original structured grid property maps. 
     
     
         9 . The method of  claim 1 , wherein generating a perforation of the near-well unstructured grid comprising computing an intersection point of the well trajectory and well completion data with a finite volume cell face of one or more of the plurality of grid cells penetrated by a wellbore of the well. 
     
     
         10 . The method of  claim 1 , comprising providing a graphical user interface to a user, the graphical user interface comprising an interface for specifying the input data. 
     
     
         11 . The method of  claim 1 , wherein the graphical user interface comprises a rendering tool for visualizing the generated unstructured grid geometry. 
     
     
         12 . The method of  claim 1 , wherein the graphic graphical user interface comprises a property analysis tool for displaying the generated unstructured grid properties. 
     
     
         13 . The method of  claim 1 , wherein the graphical user interface comprises a perforation analysis tool for displaying the generated unstructured grid perforation. 
     
     
         14 . A non-transitory tangible computer-readable storage medium having executable computer code stored thereon, the computer code comprising a set of instructions that causes one or more processors to perform the following:
 receiving, by one or more processors, input data, the input data comprising:
 a structured geocellular model or a structured reservoir simulation model having a well; and 
 well trajectory data and completion data for the well; 
   determining, by one or more processors, a field polygon based on the input data;   determining, by one or more processors, a reservoir polygon having a region of interest containing the well;   generating, by one or more processors, a plurality of grid points, the plurality of grid points comprising:
 a plurality of field grid points based on a user-specified field grid size; 
 a plurality of reservoir grid points based on a user-specified reservoir grid size for each reservoir; 
 a plurality of well grid points based on a well grid size; and 
 a plurality of parallel near-wellbore grid points on both sides of each of the plurality of well grid points based on the well grid size; 
   performing conflicting point removal and point adjustments to produce a plurality of final grid points based on a point prioritization of weights assigned to the plurality of grid points;   performing, by one or more processors, a Delaunay triangulation based on the plurality of final grid points:   generating, by one or more processors, a Voronoi grid based on the Delaunay triangulation;   generating, by one or more processors, a near-well unstructured grid model based on the Voronoi grid, the generating comprising:
 generating a geometry of the near-well unstructured grid model; 
 generating properties of the near-well unstructured grid model; and 
 generating perforation of the near-well unstructured grid model; and 
   providing, by one or more processors, the near-well unstructured grid to a parallel reservoir simulator.   
     
     
         15 . The non-transitory tangible computer-readable storage medium of  claim 14 , the computer code further comprising a set of instructions that causes one or more processors to perform the following: performing a reservoir simulation of the near-well unstructured grid via the parallel reservoir simulator. 
     
     
         16 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein plurality of grid points comprises a plurality of region of interest grid points based on a user-specified region of interest grid size for the region of interest. 
     
     
         17 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein the plurality of grid points comprises a plurality of multi-level quad-tree local grid refinement (LGR) grid points based on a user-specified number of levels and user specified near-well distances. 
     
     
         18 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein generating the geometry of the near-well unstructured grid comprises generating a 2.5D unstructured grid geometry. 
     
     
         19 . The non-transitory tangible computer-readable storage medium of  claim 18 , wherein generating the geometry of the near-well unstructured grid comprises computing a depth to a bounding surface of each grid layer. 
     
     
         20 . The non-transitory tangible computer-readable storage medium of  claim 18 , wherein the generated unstructured grid geometry comprises a layer geometry of the structured geocellular model or a structured reservoir simulation model. 
     
     
         21 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein generating properties of the near-well unstructured grid comprising applying an interpolation or point injection from a property value of the structured geocellular model or a structured reservoir simulation model to a grid point center of the near-well unstructured grid, such that the unstructured grid property maps closely match the original structured grid property maps. 
     
     
         22 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein generating a perforation of the near-well unstructured grid comprising computing an intersection point of the well trajectory data with a finite volume cell face of one or more of the plurality of grid cells penetrated by a wellbore of the well. 
     
     
         23 . The non-transitory tangible computer-readable storage medium of  claim 14 , the computer code further comprising a set of instructions that causes one or more processors to perform the following: providing a graphical user interface to a user, the graphical user interface comprising an interface for specifying the input data. 
     
     
         24 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein the graphical user interface comprises a rendering tool for visualizing the generated unstructured grid geometry. 
     
     
         25 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein the graphic graphical user interface comprises a property analysis tool for displaying the generated unstructured grid properties. 
     
     
         26 . The non-transitory tangible computer-readable storage medium of  claim 14 , wherein the graphical user interface comprises a perforation analysis tool for displaying the generated unstructured grid perforation. 
     
     
         27 . A system, comprising:
 one or more processors;   a non-transitory tangible computer-readable memory having executable computer code stored thereon, the computer code comprising a set of instructions that causes one or more processors to perform the following:
 receiving, by the one or more processors, input data, the input data comprising:
 a structured geocellular model having a well or a structured reservoir simulation model having a well; and 
 well trajectory data and completion data for the well; and 
 
 determining, by the one or more processors, a reservoir polygon having a region of interest containing the well; 
 generating, by one or more processors, a plurality of grid points, the plurality of grid points comprising:
 a plurality of field grid points based on a user-specified field grid size; 
 a plurality of reservoir grid points based on a user-specified reservoir grid size for each reservoir; 
 a plurality of well grid points based on a well grid size; and 
 a plurality of parallel near-wellbore grid points on both sides of each of the plurality of well grid points based on the well grid size; 
 
 performing conflicting point removal and point adjustments to produce a plurality of final grid points based on a point prioritization of weights assigned to the plurality of grid points; 
 performing, by the one or more processors, a Delaunay triangulation based on the plurality of final grid points: 
 generating, by the one or more processors, a Voronoi grid based on the Delaunay triangulation; 
 generating, by the one or more processors, a near-well unstructured grid based on the Voronoi grid, the generating comprising:
 generating a geometry of the near-well unstructured grid; 
 generating properties of the near-well unstructured grid; and 
 generating a perforation of the near-well unstructured grid; and 
 
 providing, over a network coupled to the one or more processors, the near-well unstructured grid to a parallel reservoir simulator. 
   
     
     
         28 . The system of  claim 27 , the computer code further comprising a set of instructions that causes one or more processors to perform the following: performing a reservoir simulation of the near-well unstructured grid via the parallel reservoir simulator. 
     
     
         29 . The system of  claim 27 , wherein the plurality of grid points comprises a plurality of multi-level quad-tree local grid refinement (LGR) grid points based on a user-specified number of levels and user specified near-well distances. 
     
     
         30 . The system of  claim 27 , wherein generating the geometry of the near-well unstructured grid comprises generating a 2.5D unstructured grid geometry. 
     
     
         31 . The system of  claim 30 , wherein generating the geometry of the near-well unstructured grid comprises computing a depth to a bounding surface of each grid layer. 
     
     
         32 . The system of  claim 27 , comprising a client computer coupled to the one or more processors, the client computer configured to provide a graphical user interface to a user, the graphical user interface comprising an interface for specifying the input data. 
     
     
         33 . The system of  claim 27 , wherein the graphical user interface comprises a rendering tool for visualizing the generated unstructured grid geometry. 
     
     
         34 . The system of  claim 27 , wherein the graphic graphical user interface comprises a property analysis tool for displaying the generated unstructured grid properties. 
     
     
         35 . The system of  claim 27 , wherein the graphical user interface comprises a perforation analysis tool for displaying the generated unstructured grid perforation. 
     
     
         36 . A non-transitory tangible computer-readable storage medium having executable computer code stored thereon for a workflow interface for generating a near-well unstructured grid, the computer code comprising a set of instructions that causes one or more processors to perform the following:
 define a workflow interface for a near-well unstructured grid builder, the workflow interface configured to:
 define input data for the near-well unstructured grid builder; 
 define gridding options for the near-well unstructured grid builder; 
 display well data of the input data in a 2D or 3D visualization; 
 provide well data and a region of interest within the input data to an unstructured grid model builder for generation of an unstructured grid; 
   display geometry of the generated unstructured grid;
 display the properties of the generated unstructured grid; and 
 display the perforation of the generated unstructured grid. 
   
     
     
         37 . The non-transitory tangible computer-readable storage medium of  claim 36 , the workflow interface comprising a graphical user interface. 
     
     
         38 . The non-transitory tangible computer-readable storage medium of  claim 36 , the workflow interface configured to well data of the input data in a 2D or 3D visualization according to user-selected colors. 
     
     
         39 . The non-transitory tangible computer-readable storage medium of  claim 36 , the workflow interface configured to well data of the input data in a 2D or 3D visualization according to user-selected colors. 
     
     
         40 . A computer-implemented method for constructing an unstructured grid, comprising:
 receiving, by one or more processors, a structured grid having a first plurality of grid points and a well of a reservoir;   determining, by one or more processors, a region of interest in the structured grid;   generating, by one or more processors, a second plurality of grid points in the region of interest according to a first grid size:   generating, by one or more processors, a third plurality of grid points outside of the region of interest according to a second grid size;   constructing, by one or more processors, a 2.5D unstructured grid from the second plurality of grid points and the third plurality of grid points; and   processing, by one or more processors, the 2.5 unstructured grid via a reservoir simulator to produce a simulation of the reservoir.   
     
     
         41 . The method of  claim 40 , comprising generating, by one or more processor, properties of the 2.5D unstructured grid based on properties of the structured grid. 
     
     
         42 . The method of  claim 40 , comprising receiving, by one or more processors, well trajectory data and completion data for the well. 
     
     
         43 . The method of  claim 40 , wherein the 2.5D unstructured grid comprises a reservoir layer geometry of the structured grid.