<div>This report presents the results from detailed palynological analyses of both newly processed samples and re-analysis of existing slides across the upper Permian to Lower Triassic section from the following wells across the southern Bonaparte Basin: Tern 3, Tern 5, Ascalon 1A, Blacktip P1, Blacktip 2, Petrel 1A, Petrel 4, Petrel 5, Prometheus 1, Rubicon 1, Torrens 1. This palynological zonal work is supplemented with palynofacies analyses in a subset of wells. In addition to these new analyses, a review of the existing palynological data from open file palynological reports (in company well completion reports) was undertaken for both the immediately under- and overlying late Permian and earliest Triassic intervals in the newly sampled wells and offset wells of the Tern and Petrel gas fields,&nbsp;including the following wells: Petrel 2, Petrel 3, Petrel 6, Tern 1, Tern 2, Tern 4.</div>

The upper Permian to Lower Triassic sedimentary succession in the southern Bonaparte Basin represents an extensive marginal marine depositional system that hosts several gas accumulations, including the Blacktip gas field that has been in production since 2009. Development of additional identified gas resources has been hampered by reservoir heterogeneity, as highlighted by preliminary results from a post drill analyses of wells in the study area that identify reservoir effectiveness as a key exploration risk. The sedimentary succession that extends across the Permian–Triassic stratigraphic boundary was deposited during a prolonged marine transgression and shows a transition in lithofacies from the carbonate dominated Dombey Formation to the siliciclastic dominated Tern and Penguin formations. Recent improvements in chronostratigraphic calibration of Australian biostratigraphic schemes, spanning the late Permian and Early Triassic, inform our review of available palynological data and re-interpretation and infill sampling of well data. The results provide a better resolved, consistent and up-to-date stratigraphic scheme, allowing an improved understanding of the timing, duration, and distribution of depositional environments of the upper Permian to Lower Triassic sediments across the Petrel Sub-basin and Londonderry High. <b>Citation:</b> Owens R., Kelman A., Khider K., Iwanec J., Bernecker T. (2022) Addressing exploration uncertainties in the southern Bonaparte Basin: enhanced stratigraphic control and post drill analysis for upper Permian plays. <i>The APPEA Journal</i> 62, S474-S479