PaleoScan™ Stratigraphic Interpretation Workflow for 3D Seismic Data in the Deltaic-Marginal Marine Environments
It is estimated that over 15% of the total reserve of siliciclastic hydrocarbon reservoirs is located in slope and basin floor areas. However, the lack of tools and the variability of the seismic data quality are causing troubles to evaluate the sand accumulation and visualize both laterally and stratigraphically the evolution of the depositional system in those areas.
On seismic data, marginal-deltaic systems are often recognized as a stack of two-dimensional surfaces with sigmoidal (sloped) geometry of clinoforms. In conventional techniques, clinoforms will be interpreted one-by-one manually which is extremely time-consuming and challenging as clinoforms are often deposited locally and periodically due to the differential compaction and sediment influx/loading.
Hereby using PaleoScan™ software, we propose an innovative workflow to extract stratigraphic insights from the seismic data and identify detailed geomorphic elements in shallow marine, marginal-deltaic environments. Thanks to the PaleoScan Full-volume, semi-automatic 3D seismic interpretation technique, all clinoform surfaces are interpreted in one attempt as a result of the Model Grid creation process (Figure 1).
Those horizon patches in Model Grid are editable and polarity-consistent, either in peak, trough, zero-crossing, or inflection points, acting as a chronostratigraphic framework for the 3D Relative Geologic Time model (or 3D Geomodel) which is the interpolation of the Model Grid (Figure 2).
From the 3D Geomodel, an unlimited number of chronostratigraphic surfaces or a Horizon Stack can be extracted, and mapped with various attributes, allowing the users to quickly scan the seismic volume both laterally and stratigraphically to understand the geological evolution of the system (Figure 3).
Also, from the 3D Geomodel, the users can build a stratigraphic framework or convert the seismic volume into an interactive Wheeler Diagram using the PaleoScan™ Sequence Stratigraphy module (Figures 4 and 5). This will allow picking the layer between two clinoform surfaces (clinothem) interactively in 3D, taking into account the vertical and lateral changes of the thickness of each clinothem (Figures 4 and 5).
Case study: F03, offshore Netherlands. Maui 3D, offshore New Zealand.