A joint MGPalaeo – Chemostrat Multi-Client study to improve the resolution and confidence of intra- and inter-field correlatable events in the Mid-Late Jurassic Birkhead Formation, Eromanga Basin. This proof of concept study provides a mechanism that can be utilized for further well correlations across the basin.
The Mid-Late Jurassic Eromanga oil play overlying the flanks of the Cooper basin continues to receive a significant amount of interest and has proven to be successful at multiple stratigraphic levels. However, these hydrocarbon-rich zones within the Birkhead and contiguous formations are typically poorly understood and difficult to correlate due to the complex stacking of fluvial – lacustrine facies.
This study reveals that the integration of palynology and chemostratigraphy is an effective tool for subdividing the Birkhead Formation–especially in sand-prone intervals and where log picking is problematic—by significantly improving well-to-well correlation at both a field and regional scale through the use of closely spaced cuttings samples.
Closely spaced sampling has enabled the subdivision of the Murospora florida spore-pollen zone derived by Geoff Wood (Santos) to be employed for the first time in this area. Previously, Wood’s subdivision has only been used in the Eastern parts of the basin.
In addition, the use of chemostratigraphy illustrates the potential of elemental data to highlight the nature and distribution of:
- Controls of reservoir quality
- Environmental indicators
- Stacking patterns & significant surfaces (core)
Palynological Dataset included in this study
- 86 high-resolution palynological samples:
- Snatcher-1 (11 cuttings samples)
- Snatcher-2 (10 core, 8 cuttings samples)
- Snatcher-3 (13 cuttings samples)
- Snatcher-11 (9 cuttings samples, 5 core samples)
- Mustang-1 (10 cuttings samples)
- Growler 2 (6 cuttings samples, 4 core samples)
- Growler 6 (6 cuttings samples, 4 core samples)
Range charts are available for all of these wells, plus well-to-well correlation panels utilizing the high-resolution palynological breakdown.
MGPalaeo has also examined five wells with core over the Late Jurassic Birkhead Formation at the South Australia Drill Core Reference Library in Tonsely, in order to gain a better understanding of depositional environments.
Snatcher 11 was described in detail, whilst Snatcher 2, Growler 2, Growler 3 and Growler 6 were reviewed.
For more information on this high-resolution integrated study, please contact Carey Hannaford at [email protected].