Australian School of Petroleum

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https://hdl.handle.net/2440/84916
This collection contains Honours, Masters and Ph.D by coursework theses from University of Adelaide postgraduate students within the Australian School of Petroleum. The material has been approved as making a significant contribution to knowledge.

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Browsing Australian School of Petroleum by Advisors "Holford, Simon Paul"

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    Evaluating structural controls on Eocene igneous activity in the Ceduna Sub-Basin, Bight Basin offshore South Australia
    (2014) Prasongtham, Pattarapong; Holford, Simon Paul; Mitchell, Andy; Australian School of Petroleum
    The presence of Middle Eocene extrusive and intrusive rocks within and overlying the Late Cretaceous to Holocene section in the Ceduna Sub-basin presents a potential risk to the associated petroleum systems, especially in exploration blocks EPP44 and EPP45. Igneous activity could possibly have reactivated normal faults in the area, resulting in the elimination of pre-existing fault-related traps. Therefore, igneous activity after hydrocarbon migration and accumulation presents an additional risk that needs to be understood. 2D seismic data was utilised in this study to assess the impact of Eocene igneous activity on hydrocarbon prospectivity in the Ceduna Sub-basin, and in particular, to evaluate the role that normal faults have played in permitting the transfer of magma to shallow crustal levels. Igneous features were mapped. Two-way time maps were generated for the bases of the Dugong, Wobbegong and Hammerhead Supersequences. Volcanogenic mounds, hydrothermal vents and sills identified on the two-way time maps appear to be spatially linked with normal faults, as they display consistent distribution along the WNW-ESE to NW-SE fault strikes. 80% of mapped volcanogenic mounds and 29% of interpreted hydrothermal vent are related to normal faults. Timing of igneous activity was likely to have occurred “at” or “after” with the last normal faulting event, based on relative chronological analysis between igneous intrusions and normal faults. All results suggest that the magma probably made its way up to shallow crustal levels by using pre-existing normal faults pathways. Fault-dependent traps in block EPP45 and the eastern part of block EPP44 appear to be at high risk of faults reactivation, due to the igneous activity in these areas. The future petroleum exploration program in the central and eastern part of Ceduna Sub-basin should take the impact of igneous activity on trap integrity into account, since fault-dependent traps are the main prospects.
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    Geocellular modelling and connectivity analysis of a tide-influenced channel belt system: example from the Mitchell River Delta, Gulf of Carpentaria, Australia
    (2014) Al Quwaitii, Reham Said; Amos, Kathryn; Holford, Simon Paul; Australian School of Petroleum
    The interaction of tidal and fluvial processes in marginal marine settings, particularly tidally influenced channel systems, can produce profound lateral and vertical facies heterogeneity, in forms such as Lateral Accretion Packages (LAPs) and Inclined Heterolithic Stratification (IHS). LAPs form at the convex banks of sinuous channels, and can be composed of either homogeneous or heterogeneous deposits. Within tidal reaches, they are often comprised of IHS deposits. IHS deposits are inclined alternating shale and sand layers that form by laterally accreting fluvial-estuarine point bars. Understanding the 3D distribution of tidally influenced channel architectures in modern channel systems has important implications for the effective modelling of subsurface channel reservoir distribution, connectivity and fluid flow. In this research, 3D geocellular modelling of a selected modern point bar from the Mitchell River system, Gulf of Carpentaria (GoC), Queensland, Australia, is used to predict heterogeneity and connectivity associated with a tidally influenced channel reservoir system. The modelling workflow consisted of four main stages: (a) data integration, (b) mapping, (c) geocellular modelling and (d) connectivity assessment. Analysis of high-resolution satellite imagery merged with Shuttle Radar Topography Mission Digital Elevation Models data for an area of 14.57 km × 2.34 km allowed direct mapping and measurement of dimensions and orientation of the stratigraphic architecture of the selected point bar geometry. Core and auger well log data and a stratigraphic cross section oriented perpendicular to the channel axis were used in order to constrain the stratigraphic architecture and the facies distribution. Five facies were identified in the studied point bar strata, including Lag Sand Deposits with rippled sandstone 2.5 m thick, which is common in upstream locations on the point bar, and heterogeneous sand and mud facies. Inclined heterolithic mud deposits (IHS) are confined to the upper 3 m of the point bar. As the focus of this project is the impact of IHS on reservoir connectivity, a new approach was proposed to resolve the heterogeneity associated with tidally influenced channel systems, by developing three geological models based on the presence and continuity of IHS deposits (the products of fluvial and tidal interaction processes). Connectivity analysis of the three realisations showed marked contrast between models using point bar geobodies. The tide-dominated, fluvial-influenced channel system represents the worst reservoir connectivity in the subsurface, as the volume contains considerable bodies of mainly mud facies. Although there are significant objects in this point bar model, the majority of these bodies are very small and supposedly form 75% mudstone of the total volume. In scenario two (Ft channel system; fluvial dominated, tidally influenced channel system), the model suggests fluid flow will preferentially concentrate in the lower part of the point bar, where clean sand sediments form a continuous body. The geo-volume in realization three (F channel system; fluvial dominated channel system) reflects the connectivity of the channel comprised of just the point bar object, which can represent best reservoir continuity and limited compartmentalization. Thus, reservoir quality increases as the fluvial process in the channel system becomes more dominant. We recommend that further field work, such as a new stratigraphic cross sections, should be obtained parallel to the channel axis in order to capture 3D heterogeneity within tidally influenced channel systems, and that the Fullbore Formation Microimager tool should be used to obtain the corrected inclination of IHS deposits.
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    The unconventional petroleum potential of the Officer Basin, Australia
    (2013) Revie, Daniel J.; Holford, Simon Paul; Amrouch, Khalid; Australian School of Petroleum
    The Officer Basin is a Neoproterozoic Basin located in Central Australia. This study looks at the unconventional prospectivity of the source rocks in the depocentres of the Officer Basin. The Savory, Gibson, Yowalga, Gibson and Lennis sub-basins are located in the Western Australian section of the Officer Basin. The Birksgate Trough, and the Munyarai, Tallaringa, and Manya Troughs, are located in the South Australian section of the Officer Basin. The Munyarai Trough contains the Observatory Hill Formation, the most prospective source rock in the Officer Basin. In the region of the Marla Overthrust Zone on the northern margin of the Munyarai Trough, the Observatory Hill Formation is the most prospective region for shale gas continuous accumulations. The thrust faulting in the Marla Overthrust Zone, and also in the Yowalga Sub-Basin, in combination with salt diapirism in these zones, poses a risk to the lateral continuity of a continuous accumulation of shale gas in these regions. The Officer Basin contains pre-Devonian source rocks which are devoid of plant material, containing algal-sourced hydrocarbons. Triaromatic hydrocarbons such as methylphenanthrene can be exploited as a measure of maturity and distribution, and have been used to map the maturity of the source rocks in the basin. The sampled data available in the underexplored Officer Basin indicates that the basin is a high risk exploration target for continuous gas accumulations. The sampled data indicates that the Officer Basin shale formations do not meet the minimum requirements outlined by the U.S. Geological Survey (USGS) for highly productive shale gas. However due to the limited sampling and exploration undertaken in the Officer Basin, there may exist other regions outside of those sampled that have the characteristics that do meet the USGS minimum requirements for highly productive shale gas systems. Three key findings of this investigation include: • The Officer Basin is a very high risk exploration target for shale gas continuous petroleum accumulations, and sampling has not been shown to meet all of the USGS minimum requirements for a highly productive shale gas system. • The Yowalga Sub-basin and the Marla Overthrust Zone contain thrust faulting and salt piercement structures related to halotectonics, affecting the lateral distribution of any continuous accumulations that may occur in the region. • The Officer Basin is underexplored, particularly in the Savory, Lennis, Gibson, Waigen and Birksgate Sub-basins, and should not be excluded from potentially hosting formations which may meet the USGS minimum requirements of a shale gas system.