Method and System For Parallel Multilevel Simulation

• US 20130116993A1
• Filed: 04/25/2011
• Published: 05/09/2013
• Est. Priority Date: 07/26/2010
• Status: Active Grant

• Current Assignee: Serguei Maliassov
• Original Assignee: Serguei Maliassov
• Inventors: Maliassov, Serguei
• Granted Patent: US 9,418,180 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: G01V 9/00 Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00
• CPC Class Codes: G06F 2111/10 Numerical modelling
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/23 using finite element methods [FEM] or finite difference methods [FDM]
• CPC Class Codes: G06F 30/28 using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]

Abstract

Exemplary embodiments of the present techniques provide methods and systems for coarsening a computational mesh, for example, for use in a reservoir simulation. An exemplary method of performing a reservoir simulation, includes generating a data representation in a storage system, wherein the data representation includes an interconnection weight that represents the magnitude of an interconnection between each of a number of computational cells in a computational mesh. A threshold value is compared to each interconnection weight and any interconnection weight that is equal to or less than the threshold value is set to zero.

Claims

1. A method of performing a reservoir simulation, comprising:

generating a data representation in a storage system, wherein the data representation comprises an interconnection weight that represents the magnitude of an interconnection between each of a plurality of computational cells in a computational mesh;

comparing a threshold value to each interconnection weight; and

setting any interconnection weight that is equal to or less than the threshold value to zero.

2. The method of claim 1, further comprising determining the threshold value, wherein determining the threshold value comprises:

calculating a maximum interconnection weight for interconnections of each of the plurality of computational cells to all adjoining computational cells;

identifying the largest value of the maximum interconnection weight for all of the plurality of computational cells;

identifying the smallest value of the maximum interconnection weights for all of the plurality of computational cells; and

selecting the threshold value to lie between the largest value and the smallest value.

3. The method of claim 2, wherein the threshold value is an average of the largest value and the smallest value.

4. The method of claim 1, wherein the data representation comprises a matrix in which each diagonal element represents one of the plurality of computational cells in the computational mesh, and the method further comprises:

generating the interconnection weights between each of the plurality of computational cells from off-diagonal elements in the matrix;

comparing the threshold value to each interconnection weight, and, for each of the plurality of computational cells that have an interconnection weight equal to or less than the threshold value, setting the off-diagonal elements to zero; and

eliminating any rows in the matrix that have no remaining off-diagonal elements to generate a lower level matrix.

5. The method of claim 4, further comprising:

iterating to create one or more additional lower level of matrices, by;

determining a new threshold value;

generating interconnection weights from the off-diagonal elements for each computational cell in the lower level matrix;

comparing the threshold value to each interconnection weight, and, for each computational cell in the lower level matrix that has an interconnection weight equal to or less than the threshold value, setting the off-diagonal elements to zero; and

eliminating any rows in the lower level matrix that have no remaining off-diagonal elements to generate a lower level matrix.

6. The method of claim 4, further comprising constructing a preconditioner by restricting the solution to the lower level matrix.

7. The method of claim 4, comprising constructing a preconditioner by iteratively restricting the solution to each higher level matrix, starting from a lowest level matrix and proceeding to a highest level matrix.

8. The method of claim 1, further comprising generating a lower level computational mesh in the storage system by eliminating any one of the plurality of computational cells from the computational mesh that has no interconnections to other computational cells.

9. The method of claim 8, further comprising generating a sequence of lower level computational meshes in the storage system by iteratively:

generating a new threshold value for the lower level computational mesh;

comparing a threshold value to each interconnection weight and setting any interconnection weight that is equal to or less than the threshold value to zero; and

eliminating any computational cell from the computational mesh that has no interconnections to other computational cells to create a next lower level computational mesh.

10. The method of claim 9, further comprising:

generating a preconditioner that restricts a solution to a lowest level computational mesh; and

, iteratively,

generating a preconditioner that restricts the solution to a next higher computational mesh until a highest level computational mesh is reached.

11. The method of claim 10, comprising using a preconditioner in a Krylov-type iterative methods to perform a reservoir simulation.

12. The method of claim 11, wherein the Krylov-type iterative method comprises gradient minimal residual (GMRES) or biconjugate gradient stabilized (BiCGStab).

13. A method for managing hydrocarbon production from a reservoir, comprising:

simplifying a computational mesh by;

generating a data representation of the computational mesh in a storage system, wherein the data representation comprises an interconnection weight that represents the magnitude of an interconnection between each of a plurality of computational cells in the computational mesh;

comparing a threshold value to each interconnection weight and setting any interconnection weight that is equal to or less than the threshold value to zero;

eliminating any of the plurality of computational cells from the computational mesh that has no interconnections to other computational cells to create a lower level computational mesh; and

generating a preconditioner by restricting a solution to the lower level computational mesh; and

simulating a hydrocarbon reservoir using the preconditioner.

14. The method of claim 13, further comprising:

generating a sequence of lower level computational meshes in the storage system by iteratively;

generating a new threshold value for the lower level computational mesh;

comparing a threshold value to each interconnection weight and setting any interconnection weight that is equal to or less than the threshold value to zero; and

eliminating any computational cell from the computational mesh that has no interconnections to other computational cells to create a next lower level computational mesh; and

generating a preconditioner that restricts a solution to a lowest level computational mesh; and

iteratively generating a preconditioner that restricts a solution to a next higher computational mesh until a highest level computational mesh is reached.

15. The method of claim 13, further comprising identifying new locations for production wells or injection wells based, at least in part, upon a result from the simulation of the hydrocarbon reservoir.

16. The method of claim 13, further comprising determining whether to convert a production well into an injection well, convert an injection well into a production well, or any combinations thereof, based, at least in part, on a result from the simulation of the hydrocarbon reservoir.

17. A non-transitory, computer readable medium, comprising code configured to direct a processor to:

generate a data representation in a storage system, wherein the data representation comprises an interconnection weight that represents the magnitude of an interconnection between each of a plurality of computational cells in a computational mesh;

compare a threshold value to each interconnection weight; and

set any interconnection weight that is equal to or less than the threshold value to zero.

18. The non-transitory, computer readable medium of claim 17, further comprising code configured to direct the processor to:

calculate a maximum interconnection weight for interconnections of each of the plurality of computational cells to all adjoining computational cells; and

identify the largest value of the maximum interconnection weight for all of the plurality of computational cells;

identify the smallest value of the maximum interconnection weight for all of the plurality of computational cells; and

select the threshold value to lie between the largest value and the smallest value.

19. The non-transitory, computer readable medium of claim 17, further comprising:

a matrix in which each diagonal element represents one of the plurality of computational cells in the computational mesh; and

code configured to direct the processor to;

generate the interconnection weights between each of the plurality of computational cells from off-diagonal elements in the matrix;

compare the threshold value to each interconnection weight, and for each of the plurality of computational cells that have an interconnection weight equal to or less than the threshold value, setting the off-diagonal elements to zero; and

eliminate any rows in the matrix that have no remaining off-diagonal elements to generate a lower level matrix.

20. The non-transitory, computer readable medium of claim 17, further comprising code configured to direct the processor to construct a preconditioner by restricting the solution to a lower level matrix.