Facies analysis, sequence stratigraphy and diagenesis of the Late Permian Muggleton Formation and Lorelle Sandstone Member on the Roma Shelf, Bowen Basin, Queensland
Honours Degree 2010
University of Adelaide
The Muggleton Formation on the Roma Shelf of the Bowen Basin, Queensland is considered as poor reservoir quality based on previous exploration data. There was gas show; however, no commercial gas flow rates were recorded from this formation. This study re-evaluates the reservoir potential of the Muggleton Formation from recovered cores of Wallumbilla South-5. Sedimentary core logging of 62 meters of Muggleton Formation from this well was conducted to do lithofacies, facies association, and depositional environment interpretation. The Lorelle Sandstone, the middle unit of the Muggleton Formation, is interpreted as a floodplain environment rather than marginal marine as previous workers have interpreted. Total 16 thin sections were prepared from the Muggleton Formation, covering all three units of the Muggleton Formation. Petrologic analysis shows that the Muggleton Formation has a similar diagenetic history to the overlying Tinowon Formation which has commercial gas flow rates from several wells. Interconnected secondary porosity and primary porosity are observed from thin-sections. No clay identification analysis was done and is recommended for future investigation. Possible formation damage of the Muggleton Formation via clay migration is argued. Petrophysial analysis also shows possible formation damage and reservoir transition zone within Wallumbilla South-5. The Lorelle Sandstone, which might have been affected by formation damage, is concluded to have outstanding reservoir potential with good primary porosity, interconnected secondary porosity, and strong gas shows. Further recommendations are made in the last chapter to address the great potential of the Lorelle Sandstone.