BP AIT 2004 2D velocity benchmark Copyright s BP America Inc. - No release, transfer, license, sell, trade or otherwise disclosure permitted outside of Queen’s U. BP AIT 2004 2D velocity benchmark Frederic Billette – AIT Houston Title slide Keep the title brief and to one line? The second line (in smaller type style) is for the date of the presentation – depending on your presentation, you may also need to include Location and/or Presenter’s name/s and Job title if needed – as a such a second line may be used for these purposes. Do not include unnecessary information in your presentation title – starting off with clear and simple messages will set the style and focus the audience for what is to follow.

Legal issues Data release agreement dated February 3rd, 2004 and confidentiality agreement dated September17th, 2004 specify that: You can: use the dataset internally for any purpose. Publish / show results using this dataset. Show these slides internally. Publish / show your result compared to the exact model after specific permission to be obtained from BP (billetfj@bp.com). You can not: Release, distribute or sell the dataset. Show, release, distribute or sell any material extracted form this presentation to a third party (exception specified above).

Agenda Model, data, challenges, … Queen’s U. contribution Velocity model comparison PSDM image comparison Feedback & ranking

Timeline 2003 2004 Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Data generation Data offered to the industry Exact model revealed Results collected Results distributed to the network Model generation Results analyzed QC Feedback provided Feedback to contractors

Model Generation Velocity 67km wide, 12km deep, build on a 6.25m x 6.25m grid Density

Challenges 1/3 Salt 1 - Shot migration no SRME complex overhangs rugose top salt sediment inclusion overpressure zones Complex/broken reflectivity

Challenges 2/3 Salt 2 - Shot migration no SRME multiples shallow HV anomaly channels steep dips poorly imaged flanks

Challenges 3/3 Extra salt - Shot migration with SRME shallow gas mud volcano shallow LV anomalies HV anomalies on structure flanks

Data generation 2D Finite difference acoustic modeling (variable velocity & density). Free-surface multiples are present. Data shot split-spread (streamer data provided), every surface point recording data. Shot every 50m, receiver every 12.5m. 6ms sampling. Frequency peak is 27Hz and data can be whitened up to 54Hz. The wavelength is causal and has not been 0 phased (see typical trace below), time delay can be estimated considering the zero offset traces.

Data transfer Tape or ftp download available. Document with experiment details provided. 15km of offset.. Model to be returned by June 9, 2004 when the exact model was revealed.

Data recipients Total: 25 1 oil company 13 seismic contractors 7 universities 3 research institutes 1 software company Total: 25

Presented results publicly at the EAGE 0 oil company 5 seismic contractors: CGG, Veritas, GXT, Paradigm, and Data Modeling Inc. (Calgary) 2 universities: KACST (Riyadh) and Queen’s (Kingston) 2 research institutes: SINTEF (Trondheim) and OPERA (France). 0 software company. Total: 9

Participating to BP benchmark 0 oil company 8 seismic contractors: CGG, Veritas, WesternGeco, PGS, GXT, Fairfield, Paradigm, Data Modeling Inc. (Calgary) 2 universities: DIG (Paris), Queen’s (Kingston) 2 research institutes: SINTEF (Trondheim) and OPERA (Pau) 0 software company. Total: 12

Queen’s University contributors Small team work in an university lab Professor: Gerhard Pratt Student: Drew Brenders

Queen’s U. processing flow Reduced the dataset: 1 - 7.5Hz, 1/8 shots and 1/8 receivers, 2km – 15km offset Initial smooth model using first-arrival travel time tomography Automatic velocity update without migration using waveform tomography No salt interpretation, all automatic Did not request feedback

Part1: velocity models Display information All images are vertically exaggerated 3 times DX=25m ; Dz=6.25m Images are 67km wide and 12 km deep Velocity scale goes from 1429m/s to 4790m/s (min & max in the exact model)

Exact model

Exact model: velocity contours

Queen’s University Colour usage A custom slide colour scheme has been applied

A Colour usage A custom slide colour scheme has been applied

B Colour usage A custom slide colour scheme has been applied

C Note: C did not deliver the right part of the model on time. Colour usage A custom slide colour scheme has been applied Note: C did not deliver the right part of the model on time.

C Colour usage A custom slide colour scheme has been applied Note: C delivered the right part of the model on September 1st, 2004.

D Colour usage A custom slide colour scheme has been applied

E Note: E estimated the model extra-salt only Colour usage A custom slide colour scheme has been applied Note: E estimated the model extra-salt only

F Note: left and right part have been updated independently. Colour usage A custom slide colour scheme has been applied Note: left and right part have been updated independently.

H Colour usage A custom slide colour scheme has been applied

I Colour usage A custom slide colour scheme has been applied

J Note: J estimated the sediment velocities only Colour usage A custom slide colour scheme has been applied Note: J estimated the sediment velocities only

K Colour usage A custom slide colour scheme has been applied

L Note: L estimated the model extra-salt only

Part2: migrations Display information All images are vertically exaggerated 3 times DX=25m ; Dz=6.25m Images are 67km wide and 12 km deep Model have been expanded or reduced if necessary 2D SRME has been applied No other pre or post-processing applied 2D wave-equation migration (downwards propagation only) For display purposes, low frequency outputs are presented Exact water layer has been inserted.

Exact density model

Exact model

Exact model

Queen’s University

A

B

C Note: C delivered the right part of the model on September 1st, 2004.

D

E Note: E estimated the model extra-salt only

F Note: left and right part have been updated independently.

H

I

J Note: J estimated the sediment velocities only

K

L Note: E estimated the model extra-salt only

+ Queen’s University: strengths Good long & short wavelength updates in the shallow section. Impressive resolution for some shallow anomalies. Good image of the top salt without interpretation. Good delineation of the overhangs without interpretation. See glimpses of the base salt.

- Queen’s University : weaknesses Deep part of the model not estimated. Variable velocity in salt. Too high frequency. Regularization/smoothing issues? Imaging issues with several targets, even shallow.

Ranking Process Ranking along 2 axes: 1) salt & sub-salt ; 2) extra salt sediment update. Ranking is an average after ~12 peer review. Only results provided on time were considered. Ranking is based on this test only.

Ranking Quality of salt and sub-salt model building D H B F J I C Accuracy of extra-salt sediment update A K E L

Ranking Quality of salt and sub-salt model building Tier 3 Tier 2 Tier 1 D H B Tier 1 F J I C Accuracy of extra-salt sediment update A Tier 2 K E L Tier 3

Questions?