SEG 2009 Workshop

1. SEG 2009 Workshop SEAM Phase I Model

2. SEAM Phase I Model Outline Model Overview - Structural Macro view Model scale and domain The Salt Major Sedimentary Surfaces Special surfaces (i.e. Salt, sutures, sediment raft, faults ) Adding fine layered properties within macro structure Construction process From Surfaces to Stratigrphic Grids Rock Properties. Rock Physics and Reservoirs Model properties

3. SEAM Phase I Model Model Overview – Components I) Provenance • A deep water Gulf of Mexico salt domain analogue. II) Major Structural Features • 1 Complex salt body with a rugous top, a root, and overhangs • 9 Horizons that extend across the entire model • 12 Radial faults arrayed under salt and near to the salt root stock • 1 Overturned sediment raft proximate to salt root • 2 internal sutures in salt and a heterogeneous salt cap III) Special Features in the model • Reservoirs, Difractors, SEG stamp, Fine layering, Multiple properties

4. SEAM Phase I Model Model Overview - Volume of Interest • Size and Orientation 35km EW x 40km NS x 15km Depth (27 x SEG Salt) E-W = X N-S = Y Depth=Z • XYZ Origin = (0,0,0) • Grid Size properties were built on 10m and 20m grid spacing 10m 84.1gb/property (21 billion cells = 220x SEG Salt) 20m 10.52gb/property x-y-z storage order

5. Phase I Model – A complex deep water salt model

6. 35 Km Top View

7. 40 km View from west

8. 40 km View from east

9. SEAM Phase I Model Model Overview - The major sediment horizons • Basement • Top Mother Salt • MCU (Mid Cretaceous Unconformity) • Top Olicoene/Paleogene “4_Oligocene” • Top Lower Miocene “5_Miocne_1” • Top Mid Miocene “6_Miocene_2” • Miocene Pliocene Unconformity “8_Mio_Plio_UNCF” • Top Pliocene • Water Bottom

10. A Blank Canvas

11. Flat Basement, Z=14858m

12. Top Mother Salt

13. MCU – Top Cretaceous

14. MCU – with radial faults

15. MCU – with salt removed

16. Oligocene

17. Miocene_1, top of lower Miocene

18. Miocene_2, top mid Miocene

19. Mio-Plio Unconformity - uncut

20. Pliocene - uncut

21. Water Bottom

22. SEAM Phase I Model Model Overview – Other Special Surfaces • Salt Sutures – entrained thin sediment • Overturned sediment raft • Radial Faults

23. Salt suture sufaces

24. Salt suture sufaces - zoom

25. Radial fault surfaces (12)

26. Overturned sediment raft

27. Sediment raft relative to salt - density

28. SEAM Phase I Model- Going from macro structure to fine layered detail - Model Construction Work Flow • Build salt surface - Construct patches from top and base interpretations - Merge salt patches into hermetically sealed surface. - Iterative revisions to address concerns • Construct sediment surfaces for a cellular version of the model - used both triangulated and regular 2D gridded objects - Introduce faults into surfaces and make consistent with faults • Build indicator volume to flag model regions • Form stratigraphic reservoir grids from bounding surfaces • For 7 major sedimentary units and each property (Vp,Vs, r, Rn, Rt ) - Morph properties from a local cartesian grid to a strat-grid - Transfer property from the strat grid to the global cartesian grid • Mask in salt & overturned sediment raft after property set on major units • Interpolate | average | smooth to final 10m grid

29. SEAM Phase I Model Indicator Volume 10 9 17 14 15 13 12 11 2

30. Bounding surfaces to define Pliocene reservoir grid

31. Pliocene density on UVW grid

32. Pliocene density morphed from UVW to XYZ strat-grid 421 million cells – 1 of 7 grids

33. Density transferred to Cartesian global grid turbidite fan salt channel

34. SEAM Phase I Model Model Overview – Reservoirs and Statisitics Catalogue Pleistocene 5 small turbidite fans Pliocene 2 E-W trending braided channel systems Upper Miocene 2 N-S trending braided channels in eastern half Middle Miocene 2 Large turbidite fans that enter from North Lower Miocene 2 Large turbidite fans that enter from North SEAM Channel and Turbidite Reservoirs

35. SEAM Phase I Model • Rock Properties & Physical Properties • Conceptual Framework • Rock Properties • Statistics • Channel Procedure • Turbidite procedure

36. Elastic parameter modeling from Rock properties Seismic modeling from Elastic parameters Rock Properties Vshale, Porosity, Fluids, Sat, Pressure, Resis, … Elastic Parms Vp, Vs, Dn, Cij, Q (and their reflectivities) Seismic Waves P, S, qP,S, atten/disp; EM response, Gravity Elasticity inversion for rock/reservoir properties AVO reflectivity inversion for elastic parameters Interest group on this end: Reservoir characterization and Monitoring Interest groups on this end: Imagers, Tomographers, Processors Rooting the seismic simulation back into the rock properties ( Conceptual Framework for SEAM Model )

37. The Rock Property Is The Root of Seismic Behavior • The earth model is rooted in the rock properties to force physical consistency across derived elasticity parameters! • Several independent rock properties form the “basis functions” from which all elastic parameters are consistently derived via rock physics + well statistics! • Properties(X,Y,Z) in ~ order of significance: • Vshale: varies from 0 to 1 and indicates the relative volume of sand and shale lithologies; in this case shales are taken to be interbedded with sands. • Porosity of the Sand endmember: variable and germane to fluid substitution • Porosity of the Shale endmember: variable but not involved in fluid substitution • Pore Fluid: (type and saturation) affects bulk modulus of sand via Gassmann • Resistivity: bed-normal and bed-parallel anisotropy • Net Pressure: most important for soft sands, but not significant in model • Rock physics & well statistics information: • Porosity Depth Trend: scaffold on which porosity variation is superposed • Cementation/Diagenesis: provides the steep modulus vs porosity trend • Deposition (sorting etc.): provides the shallow modulus vs porosity cross-trend • Gassmann & simple contact theory: fluid and overpressure effects • Porosity retention with burial/uplift: V contours parallel neither structure nor seafloor • Archie’s Law: for ionic flow in porous sand, also ~ modified for shales

38. SEAM STRATIGRAPHY • Rock properties based on generated statistics • Could base properties on real data statistics

39. Stratigraphic vshale section (white=sandier) Cross-section shows vshale statistics on flat UVW grid leaf turbidites leaf turbidites stacked channels not in section stacked channels sheet turbidites Cret Pal Olig Lo Mio Md Mio Up Mio Plio Pleisto sheet turbidites marl streaks

40. SUMMARY OF CHANNEL RESERVOIR ARCHITECTURE

41. Channels at one depth level. Channels are 20 m thick, and top rectangle is 35 km long (EW) X 10 km wide (NS). Two channels per depth level, 12 depth levels in the channel complex for a total complex thickness of 240 meters. Each level of the 12 has a different but statistically similar pair of channels. The main statistical features of the channels (length, width, thickness, sinuosity, vshale distribution) come from real world measurements of hi-res seismic and outcrop observations. Zoom of above, ~ 11 km long. Individual channels average ~180 m across *Within* channels, red ~ 5% vsh, light green ~ 25% vsh, blue ~ 60% vsh; Outside of channels = background shale from main model

42. SAME upper panel as in previous slide. Image of the average vshale vertically averaged through all 12 depth levels of the channel complex. Now, red ~ 50% vsh, blue ~ 80% vsh (because of partial averaging contribution from background vsh of ~100%) . The complex is just over one wavelength thick, so this image represents what a medium wavelength wave could sense. Individual channels are from 150 to 220 m wide; entire channel complex about 2 to 3 km wide Zoomed on next slide

43. Zoom of previous panel. ~ 5 km left to right. The blue-green part of the channel complex is about 1.6 km across . The individual 20 m cells are visible at this scale. Blue disk represents a dominant wavelength of about 200 meters (3000 m/s / 15 Hz). Effective imaging resolution will be poorer given noisy data, subsalt illumination, and inaccurate velocity model. Find the sweet spots in the channels.

44. SUMMARY OF TURBIDITE RESERVOIR ARCHITECTURE

45. Turbidite channels digitized from high-resolution, near surface seismic images of recent turbidites. • This and two other templates rotated and stretched to produce multiple turbidite complexes. • Each filamentary channel “dressed up” with vshale and width variations. • Full turbidite complexes superposed and scattered across the various reservoir strat levels.

46. 200 m vertical average of “dressed” turbidite vshale: white=sandier, blue=shalier Channel elements narrow distally: start at 240 m width in throat, end up 70 m wide Superposed on salt for orientation. Entire 35 km width of model shown. Yellow bars = 10 km

47. 10 km Mid Miocene Reservoirs: vshale (red = sand, white = shale) Multiple turbidite complexes. Similar fans superposed over 4 consecutive 20-m layers (80 m thick complex), followed by 40 m of shale, followed by another similar 80 m thick complex.

48. SAMPLE WELL LOGS

49. Central Model. NOTE: depths = strat cell X 20m, so gradients are not “perfect” due to lack of absolute depth warping Two Reservoir Penetrations 9Pleist 8Plio 7UpMio 6MdMio 5LoMio 4OligPaleo 3Cret gas oil oil oil turbidite reservoirs MioPlioUNCF

50. < Small Reservoir Chaotic Pleistocene < Small Reservoir < Channel Reservoir (not visible here) < Channel Reservoir < Turbidite Reservoir < Top overpressure < Turbidite Reservoir < Bot overpressure < Olig marlstones < Low coherency, low amp Paleogene < Hi amp sandy carbonates in Cret 3Cret 4OligPaleo 5LoMio 6MdMio 7UpMio 8Plio 9Pleist Example Seismic Section 1D (0-offset) Reflectivity convolved with 0-3-12-25 Hz 0-phase Ormsby bandpass filter Y=cell 1000 NOTE: These were created separately and glued together, so in this figure there is *no* reflectivity present at the macrolayer boundaries.