1. 2012 SEG/SPE/AAPG
Summer Research Workshop
Pressure and saturation estimation from 4D seismic constrained by reservoir flow simulation 53 06
*Alessandra Davolio
Célio Maschio
Denis Schiozer

2. Objective
Main research: development of methodology to integrate reservoir simulation and 4D seismic data in a quantitative way.
This work: estimation of pressure and saturation variations from 4D seismic data constrained by flux conditions.
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3. Main idea of the methodology
4D seismic
Reservoir simulation
Constraints
Smin < Sw < Smax
Pmin < Pre < Pmax
Uncertainty
analysis
Optimization
Trocaria optimization  inversion
Pre Sw
Model 1
Model 2 …
Model n
Pre Sw
Pre Sw
Pre Sw

4. Premin < Pre < Premax
Inversion procedure
Usual constraints
Swc< Sw < 1-Sor
Preb < Pre < Preover
Não entendi bem... Talvez seja melhor deixar claro no titulo o que quer com esse slide... É o que vc sugere ou o que é feito e o que vc vai sugerir mudanças?
Constraints from
multiple simulations
Smin< Sw < Smax
Premin < Pre < Premax

5. Methodology: multiple models
LOCATION
Importante que é preciso confiar na análise de incertezas
- Acho que as figuras não estão claras – ou seja – não dá para entender que para cada bloco – há um minimo e um máximo que são obtidos por todos os cenários – acrescentei texto
For each grid block: minimum (lower among all simulations) and maximum (higher among all simulations) values

6. Problem Statement (building a synthetic data set to test the methodology)
Reference
reservoir model
“Reference” seismic attributes
P,S maps
PEM
Multiple realizations
P,S min & max
values
Inversion
Algorithms
Inverted P,S maps
Inverted P,S maps
(calibrated)
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Base model
“Base” seismic attributes
P,S maps
PEM
Simplification: no scale differences between seismic and simulation data!

7. Assumptions Seismic is at simulation scale
Water injection case  above bubble point pressure (no presence of gas)
PEM – unconsolidated sand model + Gassman equations

8. Application: case studied
Uncertainties
Porosity and permeability fields
Geostatistical realizations
Faults transmissibility
Relative permeability
Kz/Kx
400 models
Example: geostatistical realizations of
porosity (left) and permeability (right) 8

9. Synthetic seismic 4D difference (without noise) P impedance
S impedance 9

10. Synthetic seismic 4D difference (with random noise) P impedance
S impedance 10

11. Application First case Inversion is run using usual constraints.
Second case
Inversion constrained by min and max extracted from 400 models simulations.
Third case
Inversion constrained by min and max extracted from some selected models simulations. Selection based on well pressure data.

12. Application: production data to select the best models
2nd case
3rd case 12

13. Expected Results 13

14. (estimated – true answer)
Results – First case
Inversion
results
LOWER LEFT CORNER
Errors
(estimated – true answer)
Constraints
Swc< Sw < 1-Sor
Pb < Pre < Pover 14

15. (estimated – true answer)
Results – Second case
Inversion
results
Errors
(estimated – true answer) 15

16. (estimated – true answer)
Results – Third case
Inversion
results
Errors
(estimated – true answer) 16

17. Results Reduces number of blocks with high error
Increases number of blocks with low error
Colocar titulo no eixo y – não acho que é trivial para quem está assistindo

18. Conclusion
It was presented a methodology that uses uncertainty analysis with reservoir simulation to constrain the estimation of dynamic properties from 4D seismic
Necessary due to problems related do 4DS (noise, resolution, scale, …)
More iterations may be necessary so each technique can constrain the other
Well data (pressure) was used to improve the constraint applied to the inversion
Promising results, specially in the estimation of water saturation variation
Next step: to use seismic information in a probabilistic approach.
Pequenas mudanças
1º item – importante falar que isso é devido a todos os problemas proveniente da S4D – ou seja – a inversão deve proporcionar algo fisicamente consistente com os cenários
2º item – can ? Ou foi usado? Troquei...
4º item – vai explicar? Continuidade? 18

19. Acknowledgments
UNISIM-UNICAMP

20. Thank you! 2012 SEG/SPE/AAPG Summer Research Workshop
*Alessandra Davolio
Célio Maschio
Denis Schiozer