1 Midland Valley Services Inc., 402 East San Antonio, Boerne, Texas 78006, USA
2 Midland Valley Exploration Ltd., 14 Park Circus, Glasgow G3 6AX, UK
Abstract: An Integrated Approach to Seismic Interpretation
and
Structural Validation in 3D
Traditionally interpretation
of geological structures from
seismic data in 2D and 3D have been validated through structural
balancing techniques as a final stage, if at all. Structural
modeling at this stage leads to inefficient iterations or to
structural inconsistencies passing through to volume and reservoir
models. This paper outlines a new technique for structurally
validating geological models evolved from seismic data as an
integral part of the
interpretation
process, drawing examples from
an area of active exploration offshore Cabinda, Africa.
The technique involves combining the use of standard seismic
interpretation
and structural modeling software. The first stage in
the process is to interpret the structural framework of the faults.
The faults are picked in the
interpretation
software and their 3D
relationships are examined in the modeling software. If any
problems in the
interpretation
are highlighted the picks are
re-examined in the
interpretation
software.
Once a satisfactory fault
network has been produced the
stratigraphic
horizons can be interpreted. The markers are picked
on a
fault
block by
fault
block basis. As each horizon
fault
block
interpretation
is completed, the surfaces are validated in the
modeling software. The techniques available for validation include
both kinematic (move-on-
fault
) and non-kinematic (jigsaw fitting)
types of restoration.
Using examples from offshore Cabinda we will show how this methodology has helped in imaging strike-slip faults, extensional faults and their associated tip structures, branch lines, splays and transfer faults together with the footwall and hangingwall deformation related to these features. In addition we will highlight how this method, when applied correctly, can help in imaging structures in areas where the seismic data quality is poor.
The technique produces an improved structural model within the timeframe of a standard project and hence reduces technical risk.
AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas