SEG Post-Convention WorkshopSEAM Phase 1: Initial results

Technical and Operational Overview of the SEAM Phase I Project

Michael Fehler

SEAM Mission

Advance the science and technology of applied geophysics through a cooperative industry

effort focused on subsurface model construction and generation of synthetic data

sets for geophysical problems of importance to the resource extraction industry.

What Do We want to Accomplish?

• State-of-the-art geophysical numerical modeling

• Develop datasets for testing geophysical imaging and characterization techniques

• First model is Deepwater Gulf of Mexico– Subsalt

– Variable-density acoustic and other geophysical datasets

• SEAM Phase I (This talk)

• SEAM RPSEA (Talk at 3:15)

SEAM Operation

• Board of Directors (BOD)– Bill Abriel, Chair

– Broad overview focused on future of SEAM and SEAM/SEG relationship

• Management Committee (MC)– Kevin Bishop, Chair

– Each participating company has one vote

– Make project-specific decisions

• Steve Danbom is liaison between BOD and MC

SEAM Technical Organization

• 6 Technical Committees composed of members from participating companies– Define and implement objectives and work plans– Program Manager coordinates work by and among

committees

• Communication through regular meetings and e-community– Technical committee co-chairs meet ~monthly– Management Committee meets quarterly

• One member from each participating company• Decision making body

SEAM Technical Committees and Co-Chairs

• Model Design Committee – Joe Stefani and Richard Day

• Numerical Design Committee – Scott Morton and John Anderson with help from Bill Symes

• Acquisition Design Committee– Chuck Meeder and Adam Seitchik

• NonSeismic– Michael Frenkel and Neville Barker

• Execution Committee– Peter Wang and Dan Ebrom

• Data Storage and Distribution Committee– Stew Levin

SEAM Vendors• Numerical Simulations done by Tierra Geophysical

– Careful evaluation prior to selection by Vendor Qualification Process

• Quality Control done on simulations by Nexus Geosciences Inc.– QC procedure to evaluate quality and reliability of data

delivered by Tierra Geophysical– Regularly communicate and report to Project Manager

• Data Storage & Distribution done by Landmark Graphics– Data are stored in compressed format (10:1 compression)– Delivery of either compressed or uncompressed data– Will store model files, all model description files, simulation

data, classic datasets

Model Parameters

• Dimensions– 35 km East-West

– 40 km North-South

– 15 km deep

• Gridded model on 10 m grid– 84 GB per parameter

• Velocity Range– 1490 km/s (water) to 4800 m/s (Cretaceous)

• Density Range 1.003 gm/cc to 2.904 gm/cc

Acquisition Parameters (Phase 1 Seismic)

• Variable-density acoustic• Frequency: <1 to >25 Hz• Source-receiver separation: max 9.9 km

– Receivers in rectangular grid around source

• Shot locations: 150 m grid over entire model• Shot, receiver depths: 15 m• Receiver spacing: 30 m• Sample interval 8 ms• Trace length: 16 s• Calculation grid: 30 km (for aperture)• 60K+ shots, 450K traces/shot• 3.5 GB data volume per shot (> 200 TB total)

Source and receiver depths are 15 meters.Npoles=8 f3db=26 Npoles=2 f3db=20Npoles=6 f3db=24 Npoles=1 f3db=5Npoles=4 f3db=22

Source wavelet Two ghosts 30 Hz high cut

SEAM Source Wavelet

Broad bandFlat spectrum after surface ghostsCausal

Source: C. Stork, Tierra Geophysical

Source: C. Stork, Tierra Geophysical

Status of Simulations, Phase IVariable-Density Acoustic

Number of Shots

Velocity at 4 km depth

40

30

20

10

0

Nor

th

Velocity at 4 km depth

40

30

20

10

0

Nor

th

Velocity at 4 km depth

40

30

20

10

0

Nor

th

Dark Blue: in StoragePurple: QC CompleteDark Red: Simulated

40

30

20

10

0

Nor

th

7599 Shots deliveredto participants

(about 3 TB compressed)

Blue: 2793-shot Classic DatasetRed: 9-line Classic Datasets – 15 and 17 m receiver depths – free and absorbing upper surface

40

30

20

10

0

Nor

th

Next 6 Talks about SEAM Development and Results

• Model Design and Construction

• Numerical Simulation Issues

• Acquisition Design and Classic Datasets

• Data Storage & Distribution including compression

• CSEM modeling

• Gravity modeling

Discussion of Phase II Project

• Begins at 4:00

• Two major options presented– 4D

– Land

• Your input and preference are solicited