The North Perth Basin in Western Australia has seen a significant level of activity in the last 3 years, with the drilling of exploration and appraisal wells by a variety of operators and some highly published merger and acquisition deals. The drilling results and new seismic data acquisition has increased the knowledge of the variability of the main play level, the Permian Kingia and High Cliff reservoirs, which impacts on the potential future domestic gas supply for Western Australia.
This paper will discuss the how the drilling has reduced the basin wide portfolio of available gas prospects compared to 2021 and how the remaining undiscovered gas resource base has shifted due to the unsuccessful exploration wells and estimates of well deliverability. The long-term production forecast from the North Perth Basin, based on the existing gas pools and the updated undiscovered resources highlights the need to reconsider the narrative on the availability of gas for the domestic gas market.
The Permian gas play of the North Perth Basin is more complex and more difficult to predict than initially assumed, but its impact on the Western Australian economy will be significant for many years to come.

There have been several noteworthy discoveries in Early Permian reservoirs of the onshore North Perth Basin over the last ten years, beginning with the play-opening Waitsia discovery (AWE). Subsequent exploration and appraisal in the basin, whilst predominantly successful, has highlighted significant spatial variability in sedimentary styles and reservoir quality. A key component in understanding this is the ability to define regional sediment dispersal patterns from the relative significance of source terranes and impact of syn-depositional faulting.
Previous studies (e.g., Munday et al., 2021) were successful in demonstrating that automated Raman spectroscopy could identify variations in heavy mineral assemblages which indicated multiple drainage systems were sourcing Permian reservoirs. This study utilises detrital zircon ages as well as newly acquired Raman spectroscopy data to expand the scope of earlier work to analyse Kingia and High Cliff sandstones in several structural components of the onshore North Perth Basin. These data have been integrated with (ICP-OES and MS) bulk rock elemental data and petrographic data to highlight compositional variability in the reservoir units that are likely to reflect relative changes in provenance.
The results of the study confirm a number of sediment provenance changes both at key formational boundaries (e.g. top Kingia Sandstone), as well as within reservoir sandstone units which demonstrate complex intra-basinal drainage patterns and which of the principal faults were active syn-deposition.

The Kingia Sandstone has proven to be a prolific play fairway within the northern Perth Basin, with primary porosity preservation observed at depths down to 4652mSS. However, the distribution of the early Permian depositional and diagenetic facies has remained enigmatic. This is especially true given recent exploration results. Five wells drilled in the past year targeting the Kingia Sandstone have highlighted facies variability due to mixed results. As such, an opportunity exists to leverage existing well data to investigate the interplay between sediment supply and accommodation space, resulting in improved reservoir characterisation. Trough the integration of seismic, well logs, core, and petrography studies, new insights into the spatial and temporal trends governing the presence and effectiveness of the Kingia are proposed. Implications of such work include Kingia Sandstone facies models that may be extended beyond know well control to help reduce subsurface uncertainty.

The Western Australian Ministerial Taskforce on Climate Action, established in May 2021, identified the establishment of a framework for the development of CO2 sequestration as a key state government priority. Government funding from this taskforce has allowed the Geological Survey of Western Australia (GSWA) to create a new CO2 storage Atlas for the State, initially focussing on the northern Perth Basin. This part of the project commenced on 1 July 2022 and will finish on 30 June 2024. The new atlas aims to provide a regional assessment of the potential for permanent CO2 sequestration by providing new geoscience data and interpretations.
Newly collated borehole temperature data derived from open-file reports have been utilised for multi-1D temperature modelling to capture lateral variations in subsurface temperature across the northern Perth Basin. This temperature model and newly assembled regional depth maps incorporate stratigraphic revisions and reveal where reservoir units lie within the optimum CO2 storage window, thereby delineating areas likely to be prospective for CO2 storage. In addition, open-file LAS files have been recast using Python code into a unified format with consistent depth references, mnemonics, units, coordinates, and well names suitable for AI.