performance assessment between deterministic and
TRANSCRIPT
ANNUAL MEETING MASTER OF PETROLEUM ENGINEERING
The CERENA-IV synthetic dataset
28/May/2014 Instituto Superior Técnico
Performance assessment between
deterministic and geostatistical
seismic inversion methodologies.
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Table of contents
1. Overview & Objectives
2. Methods
Deterministic approaches: Model Based Inversion; Sparse Spike
Inversion
Stochastic approaches: Global Stochastic Inversion; Global Elastic
Inversion; Geostatistical Inversion of Seismic AVO data directly to facies
models
3. Work in Progress & Preliminary results
4. To do next…
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Overview & Objectives
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• Geophysical inverse problems infer
subsurface properties from a set of indirect
measurements:
d=F(m)+e
• Deterministic
• Bayesian inference frameworks are natural
ways to tackle geophysical inverse problems.
– Stochastic or geostatistical
Overview & Objectives
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• Synthetic dimensions:
– Grid size: 121x200x250
– 6 050 000 cells
• 3 normal faults
• 4 facies groups
• Constrained dataset:
– 14 wells placed randomly
– Seismic (post and pre stack)
Facies Seismic
rho Vp Vs
Well logs
Deterministic approaches
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(Adapted from Russel, 1988)
Sparse Spike Inversion (Linear Programming)
• Puts events only where the
seismic demands
• Attempts to produce the
simplest model consistent with
the seismic data
• It often produces fewer events
that are known to be true
Deterministic approaches
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Model Based Inversion
(Adapted from Russel, 1988)
• Produces a broadband, high
frequency result
• The results can be highly
dependent on the initial guess
model: filtering the model may
lessen its effect
• The effective resolution of the
seismic is enhanced
• There is a non uniqueness
problem, as with all inversion
Global stochastic approaches
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• Iterative methodologies
• Model perturbation recurs to sequential simulation and co-simulation
• Global optimizer: genetic algorithm
(Adapted from Azevedo, 2013)
Global Stochastic Inversion
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(Adapted from Azevedo, 2013)
Global Elastic Inversion
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(Adapted from Azevedo, 2013)
Geostatistical Inversion of seismic
AVO data directly to facies models
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(Adapted from Azevedo, 2013)
Work in Progress & Preliminary
Results
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Parameters used in the applied
methodologies
• Global Stochastic Inversion
• Well data, variograms
• 32 cubes
• 6 iterations
• LP Sparse Spike
• 10% sparseness
• 8Hz constraint
• Window length: 128 samples
• Model Based
• Low frequency model w/ low pass filter
5-12Hz
• 10 iterations
• Available data:
• Well logs (AI, Vp, Vs, Rho, Facies)
• Seismic data (pre and post-stack)
• wavelet
• Control data
• Original model
rho
Vp
Vs
AI
Work in Progress & Preliminary
Results – seismic assessment
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Global Stochastic Inversion Original Model Arithmetic mean AI_DSS_6_4 AI_DSS_6_14
Sparse Spike Model Based Original Model Sparse Spike
Model Based
GSI (AI_DSS_6_4)
Original Model
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Sparse Spike
Model Based
GSI (AI_DSS_6_4)
Original Model
Synthetic Seismic vs. Real Model Seismic
Inversion Method Correlation Coefficient
LP Sparse Spike 0.9691
Model Based 0.9854
GSI 0.9120
Work in Progress & Preliminary
Results – seismic assessment
Work in Progress & Preliminary
Results – AI assessment
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Sparse Spike Model Based Original Model
GSI_Variance GSI_Arithmetic mean GSI_AI_DSS_6_4 GSI_AI_DSS_6_14
Model Based Sparse Spike
GSI_AI_DSS_6_4
To do next…
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1. Apply the remaining methods to the case study
2. Fine tune the models to reach the intended correlations that
will permit assess the performance of the applied
methodologies
Thank you.
References
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• Azevedo, L. (2013). Geostatistical methods for integrating seismic reflection data into
subsurface Earth models. Lisboa: Instituto Superior Técnico.
• Caetano, H. (2009). Integration of Seismic Information in Reservoir Models: Global
Stochastic Inversion. Lisboa: Instituto Superior Técnico.
• Cooke, D., & Schneider, A. (1983). Generalized linear inversion of reflection seismic data.
GEOPHYSICS. VOL. 48. NO 6, pp. 665-676.
• Nunes, R., Soares, A., & al, e. (2012). Geostatistical Inversion of Prestack Seismic Data.
• Oldenburg, D., Scheuer, T., & Levy, S. (1983). Recovery of the acoustic impedance from
reflection seismograms. GEOPHYSICS, VOL. 48, NO. 10, pp. 1318-1337.
• Russel, B. (1988). Introduction to Seismic Inversion Methods. Calgary, Alberta: Society of
Exploration Geophysicists.
• Russell, B., & Hampson, D. (1991). Comparison of Poststack Seismic Inversion Methods.
61st Annual International Meeting - SEG, pp. 876-878.