We often field questions regarding the differences between our palynological datasets and those available open-file, so we thought it could be a good time to explain this as we announce our Acreage Release Data Packs, and to show why standardized palynological data is crucial for your geological modelling.
Open file biostratigraphic data is often a mix of vintage reports, some dating back to the 1950s and typically utilizing outdated zonation schemes, or is a mix of inhouse and industry schemes that creates more confusion than stratigraphic clarity.
For example, does your palynological dataset still contain the R. aemula Zone? Issues correlating this zone across the North West Shelf resulted in it being superseded by the C. ancorum, V. tabulata, and T. balmei zones almost a decade ago! …yet it still remains in many databases.
How about the also-defunct A. cinctum, C. halosa, and W. digitata zones? Continuing with these outdated zones (all replaced for good reasons) usually results in miscorrelations. The raw data should always be reinterpreted to the latest zonal schemes to ensure consistent recognition of these key biostratigraphic zones.
It’s the same situation in the Otway Basin, where a number of different zonation schemes have been used, further complicated by the fact that the zonal names have remained largely unchanged but the definitions of these zones have evolved. In addition, two high resolution schemes have been used in recent years, developed over different fields in the region.
An example of how geological models can vary when using open-file data and MGPalaeo’s standardized data. Move the slider all the way to the right to see the open-file data, and to the left for MGPalaeo’s standardized data. The Montara Fm is correlated differently between three wells from the Vulcan Sub-basin. The open-file correlation is based on interpreted major depositional cycles of a prograding deltaic system, as provided in the WCRs. The correlation by MGPalaeo benefits from the utilization of standardized biostratigraphic data that also recognises higher resolution subzonal assignments not available in the public domain.
These biozone inconsistencies lead to limits on the resolution achievable from the open-source biostratigraphic data. This in turn leads to limits on the resolution of any sequence stratigraphic framework that may be built using this data, and more crucially, results in erroneous geological modelling.
In order to build an accurate geological model centred on a robust sequence stratigraphic framework, accurate, quality-controlled, and consistent palynological data is a vital component – and this is not available from the open file datasets.
Simply put, you can’t correlate oranges with apples.
Similar issues arise from inconsistent lithostratigraphic nomenclature. A single sedimentary unit may have multiple names, or even more confusingly, the same name may be applied to different definitions of that stratal package! As such, without any kind of consistency in terminology or definition, no accurate correlations between wells, or on a basin-wide scale, can be made without first updating your lithostratigraphic library.
We have reviewed, reinterpreted, and standardized ALL available open file palynological and lithological data for the vast majority of wells across Australia, so you never have this problem again. This data is available for individual wells to entire basins by contacting us on info [@] mgpalaeo.com.au.
MGPalaeo’s Acreage Release Data Packs
Supporting the Australian Government’s annual Offshore Petroleum Exploration Acreage Releases, plus the Greenhouse Gas Storage Releases, and the recently announced Geothermal Acreage Releases, MGPalaeo’s Acreage Release Data Packs can provide the most up-to-date and consistent stratigraphical data for any well from spud depth to TD.
The palynological and lithostratigraphical data for all wells across and adjacent to all hydrocarbon, CCS, and geothermal permits have been fully reviewed, reinterpreted, and standardized, greatly improving the accuracy of well-to-well correlations and regional geological models.
Simply let us know which wells (or permit) you are interested in, plus the key datasets you would like, and we can provide a bespoke Data Pack for you.
For more information on our Data Packs, including available datasets, please visit our Acreage Release Data Packs page, or explore our AUSTRALIS Viewer to see what data we have available for all wells.