Method and device for determining proportion cubes

1. A method for determining at least one combined proportion cube for a facies of a geological model representing a real subsoil comprising a plurality of facies,

the method comprising:

for each facies in the plurality of facies:

receiving a reference proportion cube, said reference proportion cube having a first mean proportion;

receiving an auxiliary proportion cube;

for at least one facies in the plurality of facies:

modifying said auxiliary proportion cube, said modified auxiliary proportion cube having a second mean proportion, the second mean proportion being at a distance less than a predetermined distance from the first mean proportion;

combining said reference proportion cube and said modified auxiliary proportion cube into the combined proportion cube;

using said combined proportion cube for exploitation of hydrocarbons or gas.

2. The method according to claim 1 , in which, the combination being linear, the sum of the coefficients of said linear combination is equal to 1.

3. The method according to claim 1 , in which for each facies i in the plurality of facies:

the reference proportion cube comprises a first plurality of meshes, each of said meshes j being associated with an initial reference local proportion value r i,j 0 ,

the auxiliary proportion cube comprises a second plurality of meshes, each of said meshes j being associated with an initial auxiliary local proportion value a i,j 0 ,

for at least two facies i in the plurality of facies, the modification may comprise, for each mesh j:

a) initialization of a current auxiliary local proportion value a i,j k to a i,j 0 ;

b) determination ( 210 ) of a first current auxiliary local proportion value a i,j,redim k according at least to:

the mean of the initial reference local proportion values r i 0 for the meshes of the reference proportion cube of the facies i,

the mean of the current auxiliary local proportion values a i k for the meshes of the auxiliary proportion cube of the facies i,

the current auxiliary local proportion value a i,j k for the mesh j of the auxiliary proportion cube of the facies i;

c) determination of a second current auxiliary local proportion value a j,norm k according at least to:

the resized current auxiliary local proportion value for a i,j,redim k the facies i,

the sum of the resized current auxiliary local values a i,j,redim k for all the facies in the plurality of facies;

d) if the second mean proportion is not at a distance less than a predetermined distance from the first mean proportion, reiteration of steps a) to c) replacing the initial reference local proportion value a i,j 0 with a j,norm k ;

and in which the modification is made in parallel for the at least two facies.

4. The method according to claim 1 , in which

for each facies i,

the reference proportion cube comprises a first plurality of meshes, each of said meshes j being associated with an initial reference local proportion value r i,j 0 ,

the auxiliary proportion cube comprises a second plurality of meshes, each of said meshes j being associated with an initial auxiliary local proportion value a i,j 0 ,

for at least two facies i in the plurality of facies, the modification may comprise, for each mesh j;

a) initialization of a current auxiliary local proportion value a i,j k to a i,j 0 ;

b) determination of a first current auxiliary local proportion value a i,j,redim k according at least to:

the mean of the initial reference local proportion values r i 0 for the meshes of the reference proportion cube of the facies i,

the mean of the current auxiliary local proportion values a i k for the meshes of the auxiliary proportion cube of the facies i,

the current auxiliary local proportion value a i,j k for the mesh j of the auxiliary proportion cube of the facies i;

c) determination of a second current auxiliary local proportion value a j,norm k according at least to;

the resized current auxiliary local proportion value a i,j,redim k for the facies i,

the sum of the resized current auxiliary local values a i,j,redim k for all the facies, in the plurality of facies;

d) if a number of reiterations of steps a) to c) is less than a given threshold, reiteration of steps a) to c) replacing the initial reference local proportion value a i,j 0 with a j,norm k ;

and in which the modification is made in parallel for the at least two facies.

5. The method according to claim 1 , for the at least one facies i in the plurality of facies, the reference proportion cube comprising a first plurality of meshes, each of said meshes j being associated with an initial reference local proportion value r i,j 0 , the auxiliary proportion cube comprising a second plurality of meshes, each of said meshes j being associated with an initial auxiliary local proportion value a i,j 0 ,

in which the modification comprises, for each mesh j:

determination of a first current auxiliary local proportion value a i,j,redim k according at least to:

the mean of the initial reference local proportion values r i 0 for the meshes of the reference proportion cube of the facies i,

the mean of the current auxiliary local proportion values a i 0 for the meshes of the auxiliary proportion cube of the facies i,

the current auxiliary local proportion value a i,j 0 for the mesh j of the auxiliary proportion cube of the facies i.

6. The method according to claim 3 , in Which the first current auxiliary local proportion value a i,j,redim k is a function of

a

i

,

j

k

·

r

i

0

_

a

i

k

_

.

7. The method according to claim 5 , in which the first current auxiliary local proportion value a i,j,redim k is a function of

a

i

,

j

0

·

r

i

0

_

a

i

0

_

.

8. The method according to claim 3 , in which the second current auxiliary local proportion value a i,j,norm k is a function of

a

i

,

j

,

re

⁢

⁢

dim

k

∑

w

=

1

⁢

a

w

,

j

,

re

⁢

⁢

dim

k

with a facies contained in the plurality of facies.

9. A device with a processor for determining at least one combined proportion cube for a facies of a geological model representing a real subsoil comprising a plurality of facies,

the device comprising:

an interface for receiving a reference proportion cube, said reference proportion cube having a first mean proportion;

an interface for receiving an auxiliary proportion cube;

a circuit suitable for at least one facies of the plurality of facies:

modifying said auxiliary proportion cube, said modified auxiliary proportion cube having a second mean proportion, the second mean proportion being at a distance less than a predetermined distance from the first mean proportion;

combining said reference proportion cube and said modified auxiliary proportion cube into the combined proportion cube;

using said combined proportion cube for exploitation of hydrocarbons or gas.

10. A non-transitory computer readable storage medium, having stored thereon a computer program comprising program instructions, the computer program being loadable into a data-processing unit and adapted to cause the data-processing unit to carry out the determination of at least one combined proportion cube for a facies of a geological model representing a real subsoil comprising a plurality of facies,

the determination of at least one combined proportion cube comprising the steps of:

for each facies in the plurality of facies:

receiving a reference proportion cube, said reference proportion cube having a first mean proportion;

receiving an auxiliary proportion cube;

for at least one facies in the plurality of facies:

modifying said auxiliary proportion cube, said modified auxiliary proportion cube having a second mean proportion, the second mean proportion being at a distance less than a predetermined distance from the first mean proportion;

combining said reference proportion cube and said modified auxiliary proportion cube into the combined proportion cube;

using said combined proportion cube for exploitation of hydrocarbons or gas.