Wheeler Diagram: Unraveling the depositional system from 2D seismic data In the early days of hydrocarbon exploration, the focus was on finding structural traps. Then, the relat...
Wheeler Diagram: Unraveling the depositional system from 2D seismic data
In the early days of hydrocarbon exploration, the focus was on finding structural traps. Then, the relationships between seismic reflection patterns, geologic time and sedimentation processes were discovered. The science of seismic sequence stratigraphy was born, which opened the way to finding stratigraphic traps.
dGB Earth Sciences developed it’s Sequence Stratigraphic Interpretation System (OpendTect SSIS https://lnkd.in/d8feYYKf) to help geoscientists establish a better seismic stratigraphic framework, to reduce critical risk in exploration, and to find hydrocarbon accumulations in stratigraphic traps. The automated Wheeler transform is an important instrument in this interpretation workflow. A Wheeler transformation flattens the seismic data along the horizons of a HorizonCube (a dense set of auto-tracked and/or modelled horizons https://lnkd.in/dJGFbwQB).
Analyzing data in a Wheeler domain helps interpreters to predict reservoir age, system tracts and areas of prospectivity. OpendTect is the only system in the market that offers HorizonCube / SSIS interpretation solutions for both 2D and 3D seismic data.
The example below is a 2D line from the Taranaki basin in New Zealand. As the first step in OpendTect’s SSIS workflow, a 2D auto tracker is applied to the target interval to generate the dense set of horizons. The densely mapped stratigraphic surfaces shown in video are automatically transformed into the Wheeler domain. The coloured lines represent the HorizonCube.
In the Wheeler scene or domain, the seismic data is flattened along chronostratigraphic horizons that honor truncations and depositional hiatuses as shown in the movie. The vertical axis of the Wheeler domain is Relative Geologic Time. The interpretation is done simultaneously by inspecting HorizonCube events in the structural domain and in the Wheeler domain. Interpreting in this way helps to identify unconformity surfaces, accommodation spaces, and any other depositional patterns.
Author: Hesham Refayee #OpendTect
