Using Simple
Validation Techniques to Minimise Uncertainty When Assessing Multiple
Structural Interpretations
Bond, Clare E.1, Alan Gibbs2,
Zoe K. Shipton1, Serena Jones3 (1) Glasgow University,
Glasgow, United Kingdom (2) Midland Valley Exploration Ltd, Glasgow, United
Kingdom (3) Midland Valley Exploration Limited, Glasgow, United Kingdom
Unique structural solutions that honour
sub-surface data are rare, particularly for areas of poor data quality or
complex structural geometries. Assessing and capturing the full range of
possible structural solutions to a 2D or 3D seismic dataset is challenging.
Perhaps more critical is that, within the current oil and gas workflow, we
reduce all of these possible interpretations to a single model for development
at the reservoir engineering stage. These single model solutions to complex and
‘fuzzy' datasets are used to create highly refined reservoir models that have
associated uncertainty models for petrophysical and other reservoir attributes.
These uncertainty calculations are produced with little or no consideration to
the original validity and uncertainty in the structural model.
We have asked over 400 geoscientists to
interpret a 2D seismic section, and have collated the results to capture the
range of concept models and structural interpretations. The results show that a
wide range of structural and concept models can be fitted to the data, but many
are geometrically and kinematically invalid. Analysis of the interpretation
process shows that the most successful geoscientists demonstrate an ability to
think in the 4th dimension (time) and to query their own interpretation for
evolutionary validity. These abilities have a dramatic affect on model outcome
and on the geoscientist's confidence in their model (an uncertainty indicator).
Our experiment shows that the use of simple evolutionary validation techniques
at the initial interpretation stage reduces the number of erroneous concept
models for the data and hence decreases structural uncertainty.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California