Presentation on theme: "SEG 2009 Workshop SEAM Phase I Model. Outline Model Overview - Structural Macro view Model scale and domain The Salt Major Sedimentary Surfaces Special."— Presentation transcript:
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
SEAM Phase I Model Model Overview – Components I) Provenance A deep water Gulf of Mexico salt domain analogue. 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 1 Complex salt body with a rugous top, a root, and overhangs 9 Horizons that extend across the entire model 9 Horizons that extend across the entire model 12 Radial faults arrayed under salt and near to the salt root stock 12 Radial faults arrayed under salt and near to the salt root stock 1 Overturned sediment raft proximate to salt root 1 Overturned sediment raft proximate to salt root 2 internal sutures in salt and a heterogeneous salt cap 2 internal sutures in salt and a heterogeneous salt cap III) Special Features in the model Reservoirs, Difractors, SEG stamp, Fine layering, Multiple properties Reservoirs, Difractors, SEG stamp, Fine layering, Multiple properties
SEAM Phase I Model Model Overview - Volume of Interest Size and OrientationSize and Orientation 35km EW x 40km NS x 15km Depth (27 x SEG Salt) 35km EW x 40km NS x 15km Depth (27 x SEG Salt) E-W = X N-S = YDepth=Z XYZ Origin = (0,0,0)XYZ Origin = (0,0,0) Grid SizeGrid 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
SEAM Phase I Model Model Overview - The major sediment horizons 1. Basement 2. Top Mother Salt 3. MCU (Mid Cretaceous Unconformity) 4. Top Olicoene/Paleogene 4_Oligocene 5. Top Lower Miocene 5_Miocne_1 6. Top Mid Miocene 6_Miocene_2 7. Miocene Pliocene Unconformity 8_Mio_Plio_UNCF 8. Top Pliocene 9. Water Bottom
SEAM Phase I Model 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,, 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
Pliocene density morphed from UVW to XYZ strat-grid 421 million cells – 1 of 7 grids
Density transferred to Cartesian global grid channel turbidite fan salt
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
Rock Properties & Physical Properties Conceptual Framework Rock Properties Statistics Channel Procedure Turbidite procedure SEAM Phase I Model
Rooting the seismic simulation back into the rock properties ( Conceptual Framework for SEAM Model ) 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 AVO reflectivity inversion for elastic parameters Elasticity inversion for rock/reservoir properties Elastic parameter modeling from Rock properties Seismic modeling from Elastic parameters Interest groups on this end: Imagers, Tomographers, Processors Interest group on this end: Reservoir characterization and Monitoring
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 Archies Law: for ionic flow in porous sand, also ~ modified for shales
SEAM STRATIGRAPHY Rock properties based on generated statistics Could base properties on real data statistics
Cret Pal Olig Lo Mio Md Mio Up Mio Plio Pleisto sheet turbidites stacked channels leaf turbidites marl streaks leaf turbidites stacked channels not in section Stratigraphic vshale section (white=sandier) Cross-section shows vshale statistics on flat UVW grid
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. 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 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.
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
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.
1.Turbidite channels digitized from high-resolution, near surface seismic images of recent turbidites. 2.This and two other templates rotated and stretched to produce multiple turbidite complexes. 3.Each filamentary channel dressed up with vshale and width variations. 4.Full turbidite complexes superposed and scattered across the various reservoir strat levels.
Superposed on salt for orientation. Entire 35 km width of model shown. Yellow bars = 10 km 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
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. 10 km
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 MioPlioUNCF turbidite reservoirs gas oil
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. 3Cret 4OligPaleo 5LoMio 6MdMio 7UpMio 8Plio 9Pleist < 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 Example Seismic Section
Shallow difractors in density Special Features – shallow difractors
SEAM Phase I Model Existing Model Properties VpP-wave velocity VpP-wave velocity density density R, R R n, R t normal and transverse resistivity VsShear velocity Distinctive Nature of SEAM model Geophysical Properties based on Rock properties Scale of model and fine scale statistics To elasticity and beyond - Vs is future aspiration
SEAM Phase I Model Acknowledgments Many thanks to Joe Stefani, Dean Stoughton, Edward Naylor, Joachim Blanche, Jacques Leveille for time spent constructing the model Many thanks to Joe Stefani, Dean Stoughton, Edward Naylor, Joachim Blanche, Jacques Leveille for time spent constructing the model Mike Fehler for managing a distributed process Mike Fehler for managing a distributed process To the management of sponsor companies that allowed their employees to contribute to this industry project. To the management of sponsor companies that allowed their employees to contribute to this industry project. The SEG for providing assistance and guidance. The SEG for providing assistance and guidance.