A key focus of the Exploring for the Future program was the Kidson Sub-basin, a large, underexplored and poorly understood depocentre in the southern part of the Canning Basin of Western Australia. The Canning Basin hosts proven petroleum systems and has recently become an area of interest for unconventional hydrocarbon exploration. Several formations within deeper basin depocentres are under investigation. Unconventional petroleum resource evaluation is generally dependent on an understanding of both local and regional stresses, as these exert a control over subsurface fluid flow pathways, as well as the geomechanical properties of reservoir units. Gaps exist in our understanding of these factors within the Canning Basin, and particularly the Kidson Sub-basin where wellbore coverage is sparse. This study identifies a generally NE–SW-oriented regional maximum horizontal stress azimuth from interpretation of borehole failure in five petroleum wells, and a broadly strike–slip faulting stress regime from wireline data and wellbore testing. Variations in stress regime at different crustal levels within the basin are highlighted by one-dimensional mechanical earth models that show changes in the stress regime with depth as well as by lithology, with a general shift towards a normal faulting stress regime at depths greater than ~2.5 km. <b>Citation:</b> Bailey, A.H.E. and Henson, P., 2020. Present-day stresses of the Canning Basin, WA. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

Exploring for the Future (EFTF) is an Australian Government initiative focused on gathering new data and information about potential mineral, energy and groundwater resources across northern Australia. This area is generally under-explored and offers enormous potential for industry development, as it is advantageously located close to major global markets, infrastructure and hosts many prospective regions. In June 2020, the Hon Keith Pitt MP, Minister for Resources, Water and Northern Australia, announced a four year extension to this program with an expansion in scope to cover the whole of Australia. The energy component of EFTF aims to improve our understanding of the petroleum potential of frontier Australian basins. Building an understanding of geomechanical rock properties is key to understanding both conventional and unconventional petroleum systems as well as carbon storage and sedimentary geothermal systems. Under EFTF, Geoscience Australia has undertaken geomechanical work including stress modelling, shale brittleness studies, and the acquisition of new rock property data through extensive testing on samples from the Paleo- to Mesoproterozoic South Nicholson region of Queensland and the Northern Territory and the Paleozoic Kidson Sub-basin of Western Australia. These analyses are summarised herein. Providing baseline geomechanical data in frontier basins is essential as legacy data coverage can often be inadequate for making investment decisions, particularly where unconventional plays are a primary exploration target. As EFTF increases in scope, Geoscience Australia anticipates expanding these studies to encompass further underexplored regions throughout Australia, lowering the barrier to entry and encouraging greenfield exploration. <b>Citation:</b> Bailey Adam H. E., Jarrett Amber J. M., Wang Liuqi, Dewhurst David N., Esteban Lionel, Kager Shane, Monmusson Ludwig, Carr Lidena K., Henson Paul A. (2021) Exploring for the Future geomechanics: breaking down barriers to exploration. <i>The APPEA Journal </i><b>61</b>, 579-587. https://doi.org/10.1071/AJ20039

Vertical stress is one of the three principal stresses and is an important parameter in geomechanical studies that are focussed on the prediction of pore pressure, fracture gradients, and wellbore stability. Variations of the vertical stress magnitude can be attributed to variations in lithology or diagenetic history, localised uplift, and overpressures caused by disequilibrium compaction. This study uses wellbore data from 102 open-file petroleum wells to characterise vertical stress within the onshore Canning Basin of north-western Australia. Vertical stress magnitudes are interpreted from density logs and checkshot data and at 1 km depth below the ground surface range from 20.5 MPa km-1 to 25.0 MPa km-1 with a mean value of 22.1 MPa km-1 (s.d. = 1.0 MPa km-1). Significant variation is evident within the calculated stress magnitudes, and when presented spatially, three regions of elevated vertical stress are identified: the Barbwire Terrace, the Devonian Reef Complexes of the northern Lennard Shelf, and the Mowla Terrace. Lithology, abnormal pore pressures, and tectonic uplift are investigated as potential mechanisms of the observed variation. Although abnormal pore pressures are identified, no direct correlation between overpressured areas and elevated vertical stress magnitudes is observed. The Canning Basin has an extensive history of uplift; however, there is little evidence for significant recent inversion. While uplift is likely to exert some influence over vertical stress magnitudes in the Canning Basin, the primary cause is interpreted to be lithological; areas of elevated vertical stress magnitude are also areas where thick intervals of carbonate sediments are present. Appeared in The APPEA Journal 59, pages 364-382, 17 June 2019