Multiple-point statistics (MPS) simulation with enhanced computational efficiency
AssigneeChevron U.S.A. Inc.
InventorSebastien B. Strebelle
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Abstract
An enhanced multi-point statistical (MPS) simulation is disclosed. A multiple-grid simulation approach is used which has been modified from a conventional MPS approach to decrease the size of a data search template, saving a significant amount of memory and cpu-time during the simulation. Features used to decrease the size of the data search template include: (1) using intermediary sub-grids in the multiple-grid simulation approach, and (2) selecting a data template that is preferentially constituted by previously simulated nodes. The combination of these features allows saving a significant amount of memory and cpu-time over previous MPS algorithms, yet ensures that large-scale training structures are captured and exported to the simulation exercise.
Claims16
A computer implemented method for simulating attributes in a stratigraphic grid for determining a subsurface reservoir model, wherein the computer implements the method comprising:
- (a) creating the stratigraphic grid of nodes of the subsurface reservoir model;
- (b) creating a training image representative of subsurface geological heterogeneity;
- (c) creating a coarse grid of nodes corresponding to nodes of the stratigraphic grid;
- (d) simulating attributes at the nodes of the coarse grid utilizing well data to get informed nodes;
- (e) refining the coarse grid of nodes by adding uninformed nodes to the informed nodes to create a working grid of nodes;
- (f) selecting a data template of nodes from the working grid and building a search tree using the data template and the training image;
- (g) simulating attributes for the uninformed nodes of the working grid using the search tree;
- and
- (h) repeating steps (e)-(g) until the attributes of the nodes in the stratigraphic grid of the subsurface reservoir model have been simulated;
- wherein in at least one of the refining steps (e), the ratio of informed nodes to the total number of nodes in the working grid is greater than 1/4 for a 2D grid and greater than 1/8 for a 3D grid.
A computer implemented method for simulating attributes in a stratigraphic grid for determining a subsurface reservoir model, wherein the computer implements the method comprising:
- (a) creating the stratigraphic grid of nodes of the subsurface reservoir model;
- (b) creating a training image representative of subsurface geological heterogeneity;
- (c) creating a coarse grid of nodes corresponding to nodes of the stratigraphic grid;
- (d) simulating attributes at the nodes of the coarse grid utilizing well data to get informed nodes;
- (e) refining the coarse grid of nodes by adding uninformed nodes to the informed nodes to create a working grid of nodes;
- (f) selecting a data template of nodes from the working grid and building a search tree using the data template and the training image, the data template being selected by creating a search window and selecting informed nodes and uninformed nodes from within the search window with a majority of the selected nodes being informed nodes;
- (g) simulating attributes for the uninformed nodes of the working grid using the search tree;
- and
- (h) repeating steps (e)-(g) until the attributes of all nodes in the stratigraphic grid of the subsurface reservoir model have been simulated.
Dependencies are inferred from the claim text.