SEG 2009 WorkshopSEG 2009 Workshop

SEAM Phase I ModelSEAM Phase I Model

SEAM Phase I ModelSEAM Phase I Model

OutlineOutlineModel Overview - Structural Macro viewModel Overview - Structural Macro view

Model scale and domainModel scale and domain

The SaltThe Salt

Major Sedimentary Surfaces Major Sedimentary Surfaces

Special surfaces (i.e. Salt, sutures, sediment raft, faults ) Special surfaces (i.e. Salt, sutures, sediment raft, faults )

Adding fine layered properties within macro structureAdding fine layered properties within macro structure

Construction processConstruction process

From Surfaces to Stratigrphic GridsFrom Surfaces to Stratigrphic Grids

Rock Properties.Rock Properties.

Rock Physics and Reservoirs Rock Physics and Reservoirs

Model propertiesModel properties

SEAM Phase I ModelSEAM Phase I Model

Model Overview – ComponentsModel Overview – Components

I) ProvenanceI) Provenance A deep water Gulf of Mexico salt domain analogueA deep water Gulf of Mexico salt domain analogue ..

II) Major Structural FeaturesII) Major Structural Features 1 Complex salt body with a rugous top, a root, and overhangs1 Complex salt body with a rugous top, a root, and overhangs 9 Horizons that extend across the entire model9 Horizons that extend across the entire model 12 Radial faults arrayed under salt and near to the salt root stock12 Radial faults arrayed under salt and near to the salt root stock 1 Overturned sediment raft proximate to salt root1 Overturned sediment raft proximate to salt root 2 internal sutures in salt and a heterogeneous salt cap2 internal sutures in salt and a heterogeneous salt cap

III) Special Features in the modelIII) Special Features in the model Reservoirs, Difractors, SEG stamp, Fine layering, Multiple propertiesReservoirs, Difractors, SEG stamp, Fine layering, Multiple properties

SEAM Phase I ModelSEAM Phase I Model

Model Overview - Volume of InterestModel 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 = XE-W = X N-S = Y N-S = Y Depth=ZDepth=Z

• XYZ Origin = (0,0,0) XYZ Origin = (0,0,0) • Grid SizeGrid Size

properties were built on 10m and 20m grid spacingproperties were built on 10m and 20m grid spacing

10m 10m 84.1gb/property 84.1gb/property (21 billion cells = 220x SEG Salt)(21 billion cells = 220x SEG Salt)

20m20m 10.52gb/property 10.52gb/property

x-y-z storage orderx-y-z storage order

Phase I Model – A complex deep water salt model

Top View

35 Km

View from west

40 km

View from east

40 km

SEAM Phase I ModelSEAM Phase I Model

Model OverviewModel Overview - - The major sediment horizonsThe major sediment horizons1.1. BasementBasement

2.2. Top Mother SaltTop Mother Salt

3.3. MCU (Mid Cretaceous Unconformity)MCU (Mid Cretaceous Unconformity)

4.4. Top Olicoene/Paleogene “4_Oligocene”Top Olicoene/Paleogene “4_Oligocene”

5.5. Top Lower Miocene “5_Miocne_1”Top Lower Miocene “5_Miocne_1”

6.6. Top Mid Miocene “6_Miocene_2”Top Mid Miocene “6_Miocene_2”

7.7. Miocene Pliocene Unconformity “8_Mio_Plio_UNCF”Miocene Pliocene Unconformity “8_Mio_Plio_UNCF”

8.8. Top PlioceneTop Pliocene

9.9. Water BottomWater Bottom

A Blank Canvas

Flat Basement, Z=14858m

Top Mother Salt

MCU – Top Cretaceous

MCU – with radial faults

MCU – with salt removed

Oligocene

Miocene_1, top of lower Miocene

Miocene_2, top mid Miocene

Mio-Plio Unconformity - uncut

Pliocene - uncut

Water Bottom

SEAM Phase I ModelSEAM Phase I Model

Model Overview – Other Special Surfaces1. Salt Sutures – entrained thin sediment

2. Overturned sediment raft

3. Radial Faults

Salt suture sufaces

Salt suture sufaces - zoom

Radial fault surfaces (12)

Overturned sediment raft

Sediment raft relative to salt - density

SEAM Phase I ModelSEAM 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

SEAM Phase I Model SEAM Phase I Model Indicator VolumeIndicator Volume

2

10

15

179

13

12

11

14

Basement 1

Mother Salt 2

Cretaceous 3

Oligocene-Paleo 4

Lower Miocene 5

Middle Miocene 6

Upper Miocene 7

Pliocene 8

Pleistocene 9

Water 10

Inv. Lower Mio. 11

Inv. Olig-Paleog. 12

Inv. Cretaceous 13

Salt Suture 14

Salt 15

Hetero Salt 17

Bounding surfaces to define Pliocene reservoir grid

Pliocene density on UVW 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 ModelSEAM Phase I Model

Model Overview – Reservoirs and StatisiticsModel Overview – Reservoirs and StatisiticsCatalogueCataloguePleistocene Pleistocene 5 small turbidite fans5 small turbidite fans

Pliocene Pliocene 2 E-W trending braided channel systems2 E-W trending braided channel systems

Upper Miocene Upper Miocene 2 N-S trending braided channels in eastern half 2 N-S trending braided channels in eastern half

Middle Miocene Middle Miocene 2 Large turbidite fans that enter from North 2 Large turbidite fans that enter from North

Lower Miocene Lower Miocene 2 Large turbidite fans that enter from North 2 Large turbidite fans that enter from North

SEAM Channel and Turbidite ReservoirsSEAM Channel and Turbidite Reservoirs

Rock Properties & Physical Properties

• Conceptual Framework•Rock Properties•Statistics•Channel Procedure•Turbidite procedure

SEAM Phase I ModelSEAM Phase I Model

Rooting the seismic simulation back into the rock properties ( Conceptual Framework for SEAM Model )

Rock PropertiesVshale, Porosity, Fluids,Sat, Pressure, Resis, …

Elastic ParmsVp, Vs, Dn, Cij, Q(and their reflectivities)

Seismic WavesP, S, qP,S, atten/disp; EM response, Gravity

AVO reflectivity inversionfor elastic parameters

Elasticity inversionfor rock/reservoir properties

Elastic parameter modelingfrom Rock properties

Seismic modeling fromElastic 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 substitutionPorosity of the Shale endmember: variable but not involved in fluid substitutionPore Fluid: (type and saturation) affects bulk modulus of sand via GassmannResistivity: bed-normal and bed-parallel anisotropyNet 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 superposedCementation/Diagenesis: provides the steep modulus vs porosity trendDeposition (sorting etc.): provides the shallow modulus vs porosity cross-trendGassmann & simple contact theory: fluid and overpressure effectsPorosity retention with burial/uplift: V contours parallel neither structure nor seafloorArchie’s 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

Cre

t

P

al O

lig

Lo

Mio

Md

Mio

Up

Mio

Plio

P

leis

to

sheet turbidites

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

SUMMARY OFCHANNEL RESERVOIR ARCHITECTURE

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.

SUMMARY OFTURBIDITE RESERVOIR ARCHITECTURE

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=shalierChannel 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

SAMPLE WELL LOGS

Well x=900 y=983 cells (eroded)

0

0.2

0.4

0.6

0.8

1

0 2000 4000 6000 8000 10000 12000 14000Depth BML (m)

No

rmal

ized

Un

its

vshnorm

Vpnorm

Dnnorm

Por

Reflecnorm

Vptomonorm

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

Mio

Plio

UN

CF

turbiditereservoirs

gas

oil

oil

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.

3Cre

t 4

Olig

Pale

o

5Lo

Mio

6M

dMio

7U

pMio

8

Plio

9

Plei

st< 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

ExampleSeismicSection

Special Features – SEG density logo

Special Features – deep density difractors

Special Features – radial faults

Shallow difractors in density

Special Features – shallow difractors

SEAM Phase I ModelSEAM Phase I Model

Existing Model PropertiesExisting Model Properties• VpVp P-wave velocityP-wave velocity

• densitydensity

• RRn, R, Rt normal and transverse resistivity

• Vs Shear 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 ModelSEAM Phase I Model

AcknowledgmentsAcknowledgments• Many thanks to Joe Stefani, Dean Stoughton, Edward Many thanks to Joe Stefani, Dean Stoughton, Edward

Naylor, Joachim Blanche, Jacques Leveille for time Naylor, Joachim Blanche, Jacques Leveille for time spent constructing the modelspent constructing the model

• Mike Fehler for managing a distributed processMike Fehler for managing a distributed process• To the management of sponsor companies that allowed To the management of sponsor companies that allowed

their employees to contribute to this industry project.their employees to contribute to this industry project.• The SEG for providing assistance and guidance.The SEG for providing assistance and guidance.