AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Implications of 3-D Domain Transformation for Structural and Stratigraphic Interpretation
(1) TerraSpark Geosciences LLC, Westminster, CO.
The interpretation of depositional systems in a seismic volume is challenging because the effects of geologic structure obscure the depositional systems in the volume. Historically, this problem has been dealt with by one of two methods: Flattening the seismic volume on a horizon; Proportional or stratal slicing between pairs of horizons.
Flattening produces a volume in which the reflections are flat only near the control horizon. Proportional slicing creates a stratal sub-volume only when there is uniform rate of differential sedimentation or compaction between two horizons. Neither approach handles more complex geologic structure.
A “Domain Transformation” (DT) removes arbitrarily complicated structure from a seismic volume. It is an interpretation guided 3D transform that creates a volume consisting entirely of stratal-slices - all reflection events are flat. This volume is ideal for imaging and interpreting depositional systems because every horizontal slice represents a paleo-depositional surface. Depositional systems are readily recognized from their morphology on these slices. Other stratigraphic details are restored to the approximate position and relationships that they had at the time of deposition.
The structural effects handled by a DT include differential sedimentation/compaction, folds, faults (3D displacement removal), unconformities (including angular), canyons, salt bodies, and carbonate buildups.
A transform may be applied to co-located volumes (e.g., attributes), structural surfaces, well paths, and well logs. Any volume or interpretation created in the stratal domain may be transformed back to the structural domain. Interpreted depositional boundaries and surfaces may be transformed back to the structural domain. Using transformed attribute volumes, well paths, and logs, seismic facies analysis may be performed in an environment where the complete morphology of the depositional system is imaged.
The transformation also provides a unique means of verifying or refining a structural interpretation. Any problem or inconsistency in the interpreted structure (e.g., missing faults or horizon misties) can readily be identified and corrected in the stratal volume.
Consistent application of a DT in structural and stratigraphic interpretation workflows significantly increases the accuracy, consistency, and detail of the interpretation, while reducing interpretation cycle time, particularly for depositional systems.