Using Simulation to Address Challenges of

Subsalt Imaging in Tertiary Basins with Emphasis on Deepwater Gulf of Mexico

(Paper 23566)

Michael FehlerSEG Advanced Modeling

Project

SEG Advanced Modeling Project (SEAM)

Use numerical simulation to Reduce exploration and development risk through improvements to geophysical methods

Relevant and challenging datasets for testing Acquisition design New imaging methods Joint inversion methodologies

Advance state-of-the-art of numerical simulation

How?• Earth Model representative of GOM DW

• 35km x 40km x 15km

• Cell size 20m x 20m x 10m

• Computer generated datasets

• Outputs look like real field data

• State-of-the-art simulation codes

• Over-sampled for acquisition testing

Perspective View of SEAM Model

Figure courtesy C. Stork, Landmark Software and Services

Scope of Work• Subsalt acoustic earth model and simulation

• Extend earth model for shear velocity, anisotropic resistivity

• Non-seismic simulations:-Gravity-Electromagnetic and Magnetotelluric

• Acoustic anisotropic TTI simulation

• Elastic simulation

SEAM Model Geological Indicator Volume

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 172

10

15

179

1312

11

148

34

5

6

7

1

Rooting the Seismic Simulation to the Rock Properties Engages Several

Interest Groups

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 MonitoringJoe Stefani, Chevron

Model Properties are Derived from Log and Petrophysical Data

Reservoirs in SEAM Phase I ModelCatalogue

Pleistocene 5 small turbidite fansPliocene 2 E-W trending braided channel

systemsUpper Miocene 2 N-S trending braided channels in

eastern halfMiddle Miocene 2 Large turbidite fans that

enter from NorthLower Miocene 2 Large turbidite fans that enter from

NorthVertically integratedReservoir thickness(white indicates

thicker reservoir)

Turbidite and Stream Channel Reservoirs Defined Using

Geostatistics

Several Geophysical Parameters

Defined Using Consistent Approach

Model Testing to Design Acquisition

Tim Brice, WesternGeco

Ensure the Quality of Numerical Simulations Through the Use of Benchmark Codes

Comparison of Productionand Benchmark Simulations

SEAM PHASE I GRAVITY MODEL

Gravity at sea level calculated using GM-SYS 3D

gxx

gyy

gxzgxy

gz

gyz

gzz

CSEM Simulation Data Shows

Sensitivity to

Reservoirs on East Side of Salt

TTI Acquisition Plan• ~36,000 shots

• Vertical Seismic Profiles

on 4 wells

• Quality control

• Classic dataset extraction

• Acoustic anisotropic model; tilted axis of symmetry

• ~36,000 shots• ~440,000 surface receivers per shot

• Vertical Seismic Profiles in 4 wells

Proposed Elastic Acquisition Plan

• ~12,000 shots

• ~460,000 surface receivers per shot

• Seafloor 4-component receivers

• Vertical Seismic Profiles in 4 wells

Simulation Specifications and

Status

Simulation Specifications and

Status

SEAM Model Used for Studies of Wave

Phenomena

Finite Difference Simulation

Boundary Integral Simulation

ConclusionsSEAM Phase I is providing geophysical data of unprecedented scale

Model is robust and easily extended for uses beyond current modeling effort Honor geology, rock, and reservoir properties

Numerical datasets available for use in studying acquisition, imaging, joint imaging for exploration and reservoir assessment Joint geophysical imaging approaches

AcknowledgmentsResearch Partnership to Secure Energy for America for support (RPSEA Subcontract No. 07121-2001)

SEAM participating companies (www.seg.org/seam)

Participating company representatives to the SEAM Management Committee

SEAM Board of Directors