Method of constructing a geological model comprising setting a depositional position of stratigraphic units

Patent metadata

Field	Value
Publication number	US-9600608-B2
Application number	US-201213557632-A
Country	US
Kind code	B2
Filing date	Jul 25, 2012
Priority date	Aug 17, 2011
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

Method of constructing a geological for setting a depositional position of a stratigraphic unit. A depositional position of the stratigraphic unit is set with respect to a reference surface, to define a depositional space. The stratigraphic unit in depositional position is then calibrated to superimpose it on the initial stratigraphic unit. The wells are then positioned in this depositional space. A regular Cartesian grid is superimposed on the stratigraphic unit with a depositional position which is filled with property values characterizing the underground formation modelled by a geostatistical simulation. The values assigned to the cells of the grid are transferred to the cells of the stratigraphic mesh.

First claim

The invention claimed is:

1. A method for constructing an image of an underground formation traversed by at least one well, the image comprising a stratigraphic mesh including a plurality of stratigraphic units defined by an upper surface and a lower surface, and representing a homogeneous sedimentary layer, the stratigraphic units including a set of cells with each cell being defined by a set of nodes wherein at least one property characteristic of the formation is measured at the level of the well, comprising for each stratigraphic unit:
i. setting a depositional position of the stratigraphic unit, by using a computer to determine a position of cell nodes of the stratigraphic unit at a time of deposition of at least one reference surface contained in the stratigraphic unit, by:
a. performing an isometric unfolding of at least the reference surface;
b. defining a rotation and a translation to be applied to the at least one unfolded surface by a minimization of distances between a set of points of the at least one reference surface and corresponding points in an unfolded surface, and applying the rotation and the translation to the at least one unfolded surface to obtain a superimposition of the at least one unfolded surface with the at least one reference surface; and
c. using the superimposition to achieve visual control of setting of the depositional position and then applying an identical unfolding within the stratigraphic unit;

ii. superimposing with a computer a regular Cartesian grid on the stratigraphic unit in the depositional position;
iii. assigning with a computer a value of the at least one property characteristic of the formation to each cell of the grid, from the well measurement, a well in the depositional position and a geostatistical simulation; and
iv. transferring with a computer the values assigned to each cell of the grid to cells of the stratigraphic mesh.

2. A method as claimed in claim 1 , wherein:
the set of points of the at least one reference surface is selected by selecting vertices of the at least one reference surface with each vertex being neither on a fault fault nor in an eroded region.

3. A method as claimed in claim 1 , wherein:
the at least one unfolded reference surface is positioned in a three-dimensional space by calculating an average depth of a set of vertices of the at least one reference surface and by assigning to the set of vertices of the at least one unfolded surface the average depth.

4. A method as claimed in claim 2 , wherein:
the at least one unfolded reference surface is positioned in a three-dimensional space by calculating an average depth of a set of vertices of the at least one reference surface and by assigning to the set of vertices of the at least one unfolded surface the average depth.

5. A method as claimed in claim 1 , wherein:
setting a depositional position of the stratigraphic unit is achieved by an isometric unfolding of two reference surfaces, followed by a calibration of each unfolded surface with respect to a corresponding reference surface and by a second calibration through rotation and translation of the two unfolded reference surfaces with respect to one another, and a proportional unfolding of surfaces contained between the two reference surfaces.

6. A method as claimed in claim 2 , wherein:
setting a depositional position of the stratigraphic unit is achieved by an isometric unfolding of two reference surfaces, followed by a calibration of each unfolded surface with respect to a corresponding reference surface and by a second calibration through rotation and translation of the two unfolded reference surfaces with respect to one another, and a proportional unfolding of surfaces contained between the two reference surfaces.

7. A method as claimed in claim 3 , wherein:
setting a depositional position of the stratigraphic unit is achieved by an isometric unfolding of two reference surfaces, followed by a calibration of each unfolded surface with respect to a corresponding reference surface and by a second calibration through rotation and translation of the two unfolded reference surfaces with respect to one another, and a proportional unfolding of surfaces contained between the two reference surfaces.

8. A method as claimed in claim 4 , wherein:
setting a depositional position of the stratigraphic unit is achieved by an isometric unfolding of two reference surfaces, followed by a calibration of each unfolded surface with respect to a corresponding reference surface and by a second calibration through rotation and translation of the two unfolded reference surfaces with respect to one another, and a proportional unfolding of surfaces contained between the two reference surfaces.

9. A method as claimed in claim 5 , wherein:
the two reference surfaces correspond to the upper surface and the lower surface.

10. A method as claimed in claim 6 , wherein:
the two reference surfaces correspond to the upper surface and the lower surface.

11. A method as claimed in claim 7 , wherein:
the two reference surfaces correspond to the upper surface and the lower surface.

12. A method as claimed in claim 8 , wherein:
the two reference surfaces correspond to the upper surface and the lower surface.

13. A method as claimed in claim 5 , wherein:
the second calibration is performed by defining rotation and translation to be applied to a first unfolded surface by a minimization of distances between a set of points of the first unfolded surface and corresponding points in a second unfolded surface, and the rotation and the translation are applied to the first unfolded surface to obtain a superimposition of the unfolded surfaces.

14. A method as claimed in claim 6 , wherein:
the second calibration is performed by defining rotation and translation to be applied to a first unfolded surface by a minimization of distances between a set of points of the first unfolded surface and corresponding points in a second unfolded surface, and the rotation and the translation are applied to the first unfolded surface to obtain a superimposition of the unfolded surfaces.

15. A method as claimed in claim 7 , wherein:
the second calibration is performed by defining rotation and translation to be applied to a first unfolded surface by a minimization of distances between a set of points of the first unfolded surface and corresponding points in a second unfolded surface, and the rotation and the translation are applied to the first unfolded surface to obtain a superimposition of the unfolded surfaces.

16. A method as claimed in claim 8 , wherein:
the second calibration is performed by defining rotation and translation to be applied to a first unfolded surface by a minimization of distances between a set of points of the first unfolded surface and corresponding points in a second unfolded surface, and the rotation and the translation are applied to the first unfolded surface to obtain a superimposition of the unfolded surfaces.

17. A method as claimed in claim 9 , wherein:
the second calibration is performed by defining rotation and translation to be applied to a first unfolded surface by a minimization of distances between a set of points of the first unfolded surface and corresponding points in a second unfolded surface, and the rotation and the translation are applied to the first unfolded surface to obtain a superimposition of the unfolded surfaces.

18. A method as claimed in claim 10 , wherein:
the second calibration is performed by defining rotation and translation to be applied to a first un

Assignees

• Poudret Mathieu
• Bennis Chakib
• Rainaud Jean-François
• Ifp Energies Now

Inventors

• Poudret Mathieu
• Bennis Chakib
• Rainaud Jean-François

Classifications

• G01V2210/642

  Faults · CPC title

• G06F30/20

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• G01V20/00 Primary

  Geomodelling in general · CPC title

• G06F17/5009 Primary

  Physics · mapped topic

• G01V99/005

  Physics · mapped topic