1. Manifestation of Fluid Saturation in Scattererd Waves – Numerical Experiments and Field Study 25 September 2014 II Russian-French Workshop "Computational Geophysics" 1

2. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 2 Vladimir A. Tcheverda 1, Vadim V. Lisitsa 1, Galina V. Reshetova 1. Anastaiya S. Merzlikina 2, Valery V. Shilikov 2. Vladimir A. Pozdnyakov 3. 1 – Institute of petroleum Geology and Geophysics SB RAS, Novosibirsk 2 – Rosneft Krasnoyarsk 3 – Siberian Federal University, Russia

3. This study is done thanks to PRACE * Access Grant # 2012071274: 32 million core-hours on supercomputer HERMIT at Stuttgart University 25 September 2014 II Russian-French Workshop "Computational Geophysics" 3 Acknowledgements: * Partnership for Advanced Computing in Europe

4. Content 25 September 2014 II Russian-French Workshop "Computational Geophysics" 4 1.Carbonate reservoirs. Fracture corridors. 2.Scattered waves. 3.Scattered waves’ simulation

5. Content 25 September 2014 II Russian-French Workshop "Computational Geophysics" 5 1.Carbonate reservoirs. Fracture corridors. 2.Scattered waves. 3.Scattered waves’ simulation

6. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 6 “It is estimated that more than 60% of the world's oil and 40% of the world's gas reserves are held in carbonate reservoirs.” (http://www.slb.com/services/technical_challenges/carbonates.aspx) Oil in carbonate reservoirs

7. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 7 Oil in carbonate reservoirs

8. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 8 Oil in carbonate reservoirs

9. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 9 Acquisitions and deep wells

10. 10 Common situation for reservoirs in the carbonate environment: oil is accumulated in caverns, but permeability is determined mainly by fractures. Rock matrix is not permeable. Cavernous/fractured reservoirs 25 September 2014 II Russian-French Workshop "Computational Geophysics"

11. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 11 Core samples from Yurubcheno-Tohomskoe oil field No cavities With cavities

12. FC – fracture corridors BFC – bed controlled fracture MBF – multibed fractures HPF – highly persistent fractures 25 September 2014 12 II Russian-French Workshop "Computational Geophysics" Variety of fractures in the carbonate environment (following J.-P.Petit et al.)

13. Fracture corridors 25 September 2014 II Russian-French Workshop "Computational Geophysics" 13 Recovery of fracture corridors is of great importance in order to ensure effective oil field development.

14. 25 September 2014 14 II Russian-French Workshop "Computational Geophysics" Uncovered (outcrop) fracture corridor

15. Content 25 September 2014 II Russian-French Workshop "Computational Geophysics" 15 1.Carbonate reservoirs. Fracture corridors. 2.Scattered waves. 3.Scattered waves’ simulation.

16. Scattered waves 25 September 2014 II Russian-French Workshop "Computational Geophysics" 16 Regular seismic technology based on reflected waves cannot reconstruct the fine structure of a fractured reservoir: resolution of standard seismic techniques is of a few meters at best, while the typical thickness of fracture corridors does not exceed a few tens of centimeters. Fortunately, these objects generate scattered waves which can deliver important knowledge about fine interior of hydrocarbon collectors.

17. Scattered waves and fracture orientation 25 September 2014 II Russian-French Workshop "Computational Geophysics" 17

18. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 18 Model (thanks to Pierre Thore)

19. Closer look, top 25 September 201419 II Russian-French Workshop "Computational Geophysics"

20. Closer look, x-line 25 September 201420 II Russian-French Workshop "Computational Geophysics"

21. Closer look, in-line 25 September 201421 II Russian-French Workshop "Computational Geophysics"

22. Wavefield inside the reservoir, top view 25 September 201422 II Russian-French Workshop "Computational Geophysics"

23. Wavefield inside the reservoir, top view. P-wave scattering 25 September 201423 II Russian-French Workshop "Computational Geophysics"

24. Wavefield inside the reservoir, top view. S-wave scattering 25 September 201424 II Russian-French Workshop "Computational Geophysics"

25. Wavefield, x-line view 25 September 201425 II Russian-French Workshop "Computational Geophysics"

26. Wavefield, x-line view 2625 September 2014 II Russian-French Workshop "Computational Geophysics"

27. Wavefield, in-line view 25 September 201427 II Russian-French Workshop "Computational Geophysics"

28. In-line Cross-line 25 September 201428 II Russian-French Workshop "Computational Geophysics"

29. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 29 Azimuth distribution of scattering energy

30. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 30 Azimuth distribution of scattering energy and fracture orientation: Real data Distribution of fractures in the well by FMI (Formation MicroImager) scanner Azimuth distribution of scattered energy

31. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 31 Scattered waves and fluid saturation

32. Real life cubes 25 September 2014 II Russian-French Workshop "Computational Geophysics" 32 Seismic cubes Permeability

33. Fluid saturation and scattered waves 25 September 2014 II Russian-French Workshop "Computational Geophysics" 33

34. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 34 Fluid saturation and scattered waves: synthetic

35. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 35 Fluid saturation and scattered waves: real data

36. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 36 Fluid saturation and scattered waves: real data

37. Fluid saturation and scattered waves: real life prognostic geological map 25 September 2014 II Russian-French Workshop "Computational Geophysics" 37

38. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 38

39. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 39 Fluid saturation and scattered waves Core sample Image in scattered waves Multiple scattering

40. Content 25 September 2014 II Russian-French Workshop "Computational Geophysics" 40 1.Carbonate reservoirs. Fracture corridors. 2.Scattered waves. 3.Scattered waves’ simulation.

41. Scattered waves’ simulation Simulation of wave propagation in realistic 3D anisotropic, viscoelastic media taking into account microstructure (fractures, cracks, caverns etc.) to get a knowledge about scattered energy. How are we doing this? Time domain explicit finite-differences methods with local grid refinement in time and space. 25 September 2014 41 II Russian-French Workshop "Computational Geophysics"

42. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 42 First order system of viscoelastic wave equations

43. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 43 Artifacts Artificial reflections must be around Estimated amplitude of scattered waves (theory of single scattering) is about 0.001 – 0.01 with respect to the incident one!!

44. Local grid refinement 25 September 2014 II Russian-French Workshop "Computational Geophysics" 44 1.Fine grid should be used only where \caverns\cracks\fractures are presented in order to avoid unrealistic demands on computer resources. 2.Different grids cause artificial reflections due to different numerical dispersion. 3.These artificial reflections must be around 10 -3 - 10 -4 with respect to incident wave. 4.Finite-difference scheme must be stable.

45. Local grid refinement 25 September 2014 II Russian-French Workshop "Computational Geophysics" 45 1. Grid refinement in time and space is performed by turn:

46. Parallel implementation via domain decomposition Fine-grid area can be placed anywhere within the reference model regardless to the specific domain decomposition used in coarse-grid model. 25 September 201446 II Russian-French Workshop "Computational Geophysics"

47. Groups of PU: data exchange 25 September 2014 II Russian-French Workshop "Computational Geophysics" 47

48. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 48 Scalability 1.Optimal 3D Domain Decomposition via METIS - Serial Graph Partitioning and Fill- reducing Matrix Ordering. 2.Non-blocking send/receive procedures. 3.Computations are starting from the most interior point and are expanding towards neighboring domain 4.Send/Receive of partially sampled data

49. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 49 Scalability Strong scalability (acceleration): the size of a problem is fixed, but the number of cores increased. Ideal acceleration: N x time(N) = const, N – number of cores.

50. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 50 Strong scalability (acceleration)

51. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 51 Scalability Weak scalability: the CPU load is fixed, but the number of cores increased. Ideal WS: time(N) = const, N – number of cores.

52. Weak scalability 25 September 2014 II Russian-French Workshop "Computational Geophysics" 52

53. Road map 25 September 2014 II Russian-French Workshop "Computational Geophysics" 53 1.Development of the archive with a set of realistic synthetic models (macro+mezo+micro scales). 2.Numerical simulation of multiphysics processes: isotropy+anisotropy+attenuation+fluid saturation+fluid flow induced by seismic waves (Permeability?) +…… 3.Scattering imaging and inversion 4.Non-linear effects of seismic waves’ propagation

54. 25 September 2014 II Russian-French Workshop "Computational Geophysics" 54 Thank you for attention! Please, ask your questions!