Friso Brouwer, David Connolly, Gert de Bruin, and Paul de Groot
dGB-USA, Sugar Land, TX
Seismic data is one of the important sources of sequence stratigraphic information. Despite (or due to) the richness of sequence stratigraphic information in seismic data it is difficult to isolate, map, and interpret system tracts in 3D seismic data. However, once mapped in a Wheeler diagram, interpretation of system tracts, sea level change and shoreline shifts becomes much easier, ultimately facilitating the identification of source rock, reservoir-seal-couplets and stratigraphic traps.
We will present a workflow illustrated with case study examples in which we semi-automatic construct a Wheeler type diagram from seismic data and use a dual seismic/wheeler display for system tract interpretation. Finally, we show how detailed stratigraphic features such as channels and fans can be mapped with ease in 3D wheeler space.
The procedure depends on the accurate determination of the dip of seismic events, using a method called dip-steering. Subsequent step is the automated data driven tracking of chrono-stratigraphic horizons using the calculated dips from the previous step. The tracking is designed to honor horizon truncations at unconformable boundaries. Using the chrono-stratigraphy we transform the data from the seismic domain to the Wheeler domain, including creation of hiatuses in areas of non-deposition and erosion. A simultaneous display of amplitude data (seismic character) and chrono-stratigraphy in the seismic domain and depositional trends in the wheeler domain allows an easy and accurate interpretation of the system tracts and depositional style.
Using the information obtained in the previous step we build a 3D model-driven chrono-stratigraphy, again honoring unconformities. We use this to create a 3D wheeler space, in which time slices are equivalent to horizons slices in the seismic domain.
AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas