Seismic
Modeling
Applied to Stratigraphic Models to Assess
Seismic
Interpretation
Consistency
Cacas, Marie-Christine, Caroline Sultzer, Caroline Joseph, Emily Albouy, Institut Francais du Petrole, Rueil-Malmaison Cedex, France
Stratigraphic modelling
simulates erosion, sediment transport and deposition at basin scale and
geological time scale. It provides three-dimensional sub-surface models in
terms of isochron surfaces and sedimentary filling,
i.e. lithologic proportions between these surfaces.
Sub-surface models provided by stratigraphic
modelling can be constrained by seismic
horizons and well
data
. However, these constraints are often sparse and fuzzy, and usually allow
for multiple solution models to be proposed.
A methodology to validate or unvalidate
a solution model is proposed here. It is based on a synthetic seismic
modelling ran on the sub-surface model. The validation
consists in comparing the obtained synthetic
seismic
to the real acquired
seismic
image. Comparison criteria are basically texture attributes.
The methodology proposed here includes a down-scaling of the stratigraphic model, since stratigraphic
models discretization is usually too coarse for
seismic
modelling purposes. The down-scaling is
performed by running a non-stationnary
geo-statistical simulation. The simulation grid is built from isochron surfaces. Proportion matrices are directly given
by lithological proportions output from the stratigraphic model. Synthetic
seismic
modelling
is a simple 1D convolution.
This methodology
is applied to real data
at basin scale and to synthetic geological environments
modeled at the scale of a prospect. Results definitely show that this methodology
helps to discriminate between possible scenarios and hypotheses: for given
acoustic properties measured at wells, resulting synthetic
seismic
textures are
sensitive to lithology proportions and depositional
environments.