ASEG Extended Abstracts - 1st Australasian Exploration Geoscience Conference – Exploration Innovation Integration, 2018

The Northern Carnarvon Basin has experienced multiple phase of deformation, most likely starting in the Lower Palaeozoic and continuing to the present day. The widespread availability of public domain 2D and 3D seismic data sets over large parts of the basin allows mapping of structures at different stratigraphic levels in considerable detail, which in turn enables spatial relationships between structures of different ages to be established. Permian rifting established the fundamental underlying architecture of the basin and created the accommodation space for the accumulation of thick sequences of Triassic sediments. NE-SW trending structures were reactivated under E-W extension, starting in the latest Triassic, but the onset and magnitude of rifting is variable across the basin. The initial phase of rifting ended in the Middle Jurassic, but subsequent reactivation is variable, both spatially and temporally. Upper Jurassic to Lower Cretaceous reactivation is most evident in the easternmost and westernmost parts of the basin, and may be associated with a change in stress regime. A particularly short lived and enigmatic episode of extension occurs in the Exmouth sub-basin, associated with significant uplift and erosion. The Valanginian unconformity marks the end of most rift related activity, although minor fault reactivation occurs into the Albian. Upper Cretaceous to Recent compressional structures form at different times in different parts of the basin.

The Roebuck Basin is on Australia’s North West Shelf, between the Browse and northern Carnarvon basins. The basin consists of Paleozoic to recent fluvial to deep marine mudstones and sandstones, carbonate platforms and reefs, and volcaniclastics. Recent hydrocarbon discoveries in the Bedout Sub-basin have renewed exploration interest and changed existing perceptions about the regions prospectivity.

The interpretation of U-Pb detrital zircon dating from offshore petroleum well cuttings provides new information regarding the origin of sediments and changes in sediment provenance. This analytical work has the potential to better understand reservoir quality within the Triassic Upper and Lower Keraudren deltas (and equivalent sequences). A range of detrital zircon age spectra were obtained. Analyses of zircon grain shapes (i.e. roundness) somewhat supports transportation of some distance, but could also signify multi-phase recycling. However, the combined detrital age spectra and grain shape reveals that the Roebuck Basin deltas had multiple sediment sources. The Roebuck Basin’s Triassic sediments appear to be derived from Australia’s interior, potentially transported either directly via large rivers or from subsequent sediment reworking and transport via long-shore drift.

Seismostratigraphic interpretations have identified potential sediment transport mechanisms including clinoforms and submarine canyons. Significant landward uplift and erosion associated with the latest Permian-aged Bedout Movement supports the reworking of Permian sediments. Integration of additional samples, and linking these to palaeogeographic settings, will provide additional clarity of the potential Australian and non-Australian Triassic sediment sources. This study aims to provide further insight into the origin of the reservoir units in the Roebuck Basin.

The North West Shelf (NWS) and its associated petroleum systems have varied geographies, geomorphologies and complex geological environments. In spite of the ongoing exploration activities in many sedimentary basins, the appraisal and field development campaigns are challenging. Besides, interpreting the connectivity between petroleum systems is challenging. The heterogeneity and multidimensionality of multi-stacked reservoirs associated with multiple oil and gas fields complicate the data integration process. Volumes and varieties of data existing in these basins are in different scales, sizes and formats, demanding new storage and retrieval methods, emphasizing both data integration and data structuring. Since the data are in terabyte size; the multiple dimensions and domains need to be brought in a single repository, we take advantage of Big Data tools and technologies. In this context, we aim at articulating the digital petroleum ecosystems and petroleum database management systems, with new data modelling, data warehousing and mining, visualization and interpretation artefacts. This approach facilitates the data management not only for individual basins but groups of basins of the NWS. Warehoused cuboid metadata can explore the connections providing new insights in the data interpretation and knowledge of new prospective areas. The multidimensional warehousing repository that supported by cloud computing, data analytics and virtualization features, provide new opportunities for delivering quality and just-in-time online ecosystem services. Other goals are deducing an integrated unified metadata model and characterizing the connectivity among the basins of the NWS and associated oil & gas fields. The study supports the features of PDE and its knowledge management.

Following decades of technological innovation, geologists have now access to extensive 3D seismic datasets. How these data will help understanding the complexity of the subsurface relies on developing stratigraphic workflows that allow very high-resolution interpretation in a cost-effective timeframe. Here, the use of full-volume, semi-automatic horizon tracking tools allowed interpreting ultra-high resolution seismic sequences (^0,000 yrs duration) within a Cretaceous prograding shelf-margin (Lower Barrow Group; LBG) on the North West Shelf of Australia. Initially, semi-automated horizon tracking allowed mapping key regional unconformities defining 3^rd order seismic sequences. In a second step, a very high resolution grid (nodes corresponding to seismic traces) was generated in each 3^rd order sequence. An automatic propagation algorithm then linked the nodes based on their similarities, resulting in a very dense network of “proto”-seismic horizons. Volume interpolation resulted in the creation of a Relative Geological Time (RGT) model from which a very high number of chronostratigraphic surfaces were extracted. This allowed a full volume 3D mapping of every clinoform in each 3^rd order sequence, from which quantitative data (clinoform height, slope, topset vs bottomset thickness) and seismic attributes (seismic geomorphology) were extracted. This analysis unveiled the high resolution changes in sediment supply and accommodation in time and space in the LBG, and provided new insights on the distribution of shallow and deep marine plays in the basin. This innovative workflow constitutes a new step in sequence stratigraphy as it allows interpreters to map sequences in a true 3D environment hence taking into account the full variability of depositional systems in time and space.

The Triassic is an important interval for Australian petroleum exploration, with Middle to Upper Triassic Mungaroo Formation reservoirs in the Northern Carnarvon Basin, and recent Lower Triassic discoveries in the Roebuck Basin. The chronostratigraphic understanding of Triassic petroleum systems is underpinned by biostratigraphic dating using palynological zonations. The numerical ages of these zones are usually assigned through inference and interpolation, often via tenuous correlations to the international geologic timescale using scattered marine biota, (primarily foraminifera, and rare ammonites, conodonts and/or dinoflagellates). In contrast, we tie Australian biozones to the timescale through Chemical Abrasion-Isotope Dilution Thermal Ionisation Mass Spectrometry (CA-IDTIMS) dating of interbedded volcanic tuffs. Such ashfalls are reasonably common in Australian basins, and can provide high-precision CA-IDTIMS ages if they contain magmatic zircons. We recently recalibrated Australian middle and late Permian palynozones using this approach and preliminary results suggest that Triassic biozone ages are likewise in need of considerable revision.

We have targeted Triassic tuffs across Queensland, (Tarong beds, Brisbane Tuff, Moolayember Formation, Rewan Group), New South Wales (Garie Formation, Coal Cliff Sandstone, Milligan Road Formation), and Tasmania (upper Triassic coal measures) to provide numerical ages for palynozones. Additional dates in New Zealand (Murihiku Supergroup) and Timor-Leste (Wailuli Formation) will allow international correlation of dinocyst and spore-pollen zones. Numerical constraints for Triassic biozone boundaries facilitate correlation of Australian biozones with the international geologic timescale. This can impact burial history models used in petroleum exploration anywhere these biozones are used, often far beyond the basins from which the samples were collected.

Surface process dynamics play an important role in sedimentary basin evolution. It affects hydrologic and carbon cycling, which are particularly difficult to simulate because of their complex interactions and the large range of spatial and temporal scales on which they operate. By considering uplift/subsidence, sea level change and climate change, surface process models are able to assimilate and represent several dynamic processes, including crustal deformation, mantle-convection-driven dynamic topography, erosion, sediment deposition, burial, and compaction. In order for these models to be useful for the industry they need to be able to reproduce depositional histories in sedimentary basins. Here we propose to use Badlands (BAsin anD LANdscape DynamicS), a landscape evolution modelling software, to evaluate the topographic and sedimentary evolution of the Lake Eyre Basin, a large, dominant feature in the Australian landscape with economic resources and good data coverage. Analyses of the long-term Lake Eyre sedimentation can provide valuable information about the connection between processes operating at the Earth’s surface and the deeper mantle. From our calibrated models, we will be able to characterise reconstructions of the burial of stratigraphic layers in a sedimentary basin through space and time. Our approach will provide an integrated set of forward models and data assimilation framework which may help us better constrain source-to-sink basin models, and shed light on the contribution of mantle convection processes on the stratigraphic evolution of basins. Furthermore, data science and machine learning methods can be used in conjunction to develop surrogate-assisted models in order to assist existing model for large-scale implementation.

The Ernest Henry deposit represents the largest known Iron Oxide Copper Gold (IOCG) deposit in the Eastern Succession of the Mount Isa inlier. The orebody consists of a structurally controlled pipe-like breccia hosted in complexly altered Proterozoic volcanics with mineralization occurring post-peak metamorphism during a regional transpressional deformational event (D3). Ore formation was controlled by the mixing of magmatic, metamorphic and basal fluids, resulting in the precipitation of chalcopyrite, pyrite, calcite, quartz, magnetite and accessory gold. Coarsegrained apatite is present as an accessory mineral in areas of high sulphide mineralization and in shear zones adjacent to the orebody.

The paragenesis and relative timing of the alteration and mineralisation stages have been well constrained by previous workers. However, advances in U-Pb geochronology via the in-situ laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) method means that for the first time apatite and calcite from the ore body and adjacent structures may be suitable for age dating.

This project will use an established apatite dating technique and aims to develop a calcite dating technique to provide dates for individual paragenetic stages. These time constraints will improve the current understanding hydrothermal evolution and ore genesis at Ernest Henry. As calcite is a common accessory mineral in ore deposits, this technique could be widely implemented to date mineralization events and may allow hydrothermal events at different deposits to be linked.

The Geological Survey of NSW (GSNSW) has created a 3D geological model of the Sydney-Gunnedah Basin that includes best available geological mapping and new 3D modelling.

The onshore Sydney Basin comprises the southern section of the Permo-Triassic Sydney-Gunnedah-Bowen system, which overlies the Lachlan Orogen and Late Carboniferous volcaniclastic rocks. The Hunter-Bowen Orogeny formed the adjacent New England Orogen and resulted in uplift and erosion that deposited Jurassic sedimentary sequences of the Surat Basin over large parts of the Gunnedah Basin.

Model generation followed GSNSW’s map development workflow, developed as part of the larger project: 3D Mapping of NSW.

The integrated Sydney-Gunnedah Basin 3D model was developed with the aim of advancing the understanding of the geological and structural setting of the region. This will inform areas of investigation such as coal and hydrocarbon prospectivity, groundwater management and exploration, and environmental and land use decision making.

Rift settings preserve high-fidelity records of their depositional history in response to multiple processes, such as climate change that significantly influences the sediment input, and tectonic deformation which contributes to accommodation generation or consuming. Integrated studies of geomorphology, thermochronology, analog experiments and numerical modelling improved our understanding of the rifting processes and associated structural evolution. However, the interplay between climate change, sediment transport from eroding highland to rift basins and rift-related deformation is poorly understood.

We present a forward numerical scheme that couples surface process with thermo-mechanical modelling on a rift setting. In the coupling numerical framework, a 2D (potentially 3D) lithospheric scale model is set up. The erosion, sediment transport and deposition are controlled by surface processes with the boundary conditions of climate force (precipitation) and erosion coefficient. The resulting sediment volumes are transferred to the thermo-mechanical system, which has significant effect of crustal deformation. The produced tectonic uplift or subsidence then contributes to the change of surface topography and thus the sediment routing. We focus on investigating the climatic controls on source dynamics, sediment transport, and the deposition in both marine and nonmarine environments. We then quantify the influence of sediment accumulation on crustal deformation and rift evolution. The resulting stratigraphic architecture will be analyzed through evolving stratal stacking patterns and shoreline trajectories to explore the feedbacks between erosion/deposition patterns and the rift structural. We will then apply our modelling to typical rifting examples such as East Africa rift system.

The landscape of Papua New Guinea is very young, shaped by Plio-Quaternary tectonic events. Tectonic uplift rates exceed 400 m/Myr and rainfall exceeds 10 m/yr. Uplift and rainfall combine to generate very high erosion rates. The Gulf of Papua is the ultimate sink for a very large terrigenous flux of ~ 365’10⁶ t/yr stemming from the southern New Guinean mainland and from the Papuan Peninsula. Sediment cores indicate sediment accumulation rates of 0.12-0.8 mm/yr in the deep-sea basin since the Late Pleistocene.

Rock types and erosion rates determine the nature and burial rate of the sediments delivered to the basin. Understanding their evolution through space and time helps predict the petrological stratigraphy of the basin. We use Badlands, a surface process numerical model developed by the Basin Genesis Hub, which simulates sediment erosion, routing and deposition, in order to simulate present-day fluxes and assess their evolution in the past. To reproduce landscape evolution in deep time we need to constrain the erodibility of the source areas. To achieve this we calibrate the model over the present-day landscape, using the present-day topography, rainfall patterns, distribution of source rocks, recent surface uplift field, and estimates of Late Quaternary sediment fluxes. Relative uplift along the southern flank of the Papuan Peninsula is constrained by the elevation of remnants of extensive late Miocene volcanics and by the modern elevation of contemporary low-lying surfaces. They reveal an uplift rate that increases from 0 m/Myr at the coastline to 440 m/Myr in the headwaters.

Over the summer of 2016/17, a team of students from the University of Adelaide were brought together to develop a unique proposal for the Frank Arnott Geophysical Challenge (http://www.frankarnottaward.com), with a focus on data integration and visualisation.

Geoscientific data is critical to exploration success, yet as projects move deeper under cover it is more critical than ever to maximise the value of existing data. Our challenge was to develop a means of integrating and manipulating the data to provide a clearer picture to better tell the story of the geological structures of the Gawler Craton. For this we used Wavelet Transformations to alter 2D geophysical datasets into 3D datasets using the Poisson Wavelet and to work out the Fractal Dimensions. Subsequently we were tasked with developing an innovative method of visualising that data to give a unique experience and improve interaction and comprehension of the data. This was achieved by interactively projecting data onto a 3D surface to be able to locate areas of interest and see through the subsurface to better understand the geology.

Ultimately the aim of this project is to lend itself to the exploration industry and examine new ways to approach the challenges faced by geoscientists today and tomorrow. We developed a simple method of data integration and visualisation that uses all open source programs and accessible materials.

A study was undertaken to test whether it is possible to map basement configuration and sedimentary horizons from the gravity gradiometry (AGG) data. This was within the EP431 Buru Energy permit on the Mowla Terrace in the onshore Canning Basin.

By applying the Horizon Mapping method, using Energy Spectral Analysis Multi-Window-Test as described in the Methodology section (ESA-MWT), to AGG data, we conducted a test study on a narrow 8km long swath along 2D seismic traverse HCG-300, and at three wells: Pictor -1, Pictor-2 and Pictor East-1, with three additional wells located nearby.

ESA-MWT was applied to gridded Bouguer and tensor gravity data. The ESA-MWT procedure was conducted at stations 1km apart. At each station, multiple spectra were computed over incrementally increasing windows. For each spectrum, the depth was interpreted and plotted versus window size, and from these graphs, multiple Depth-Plateaus were detected at each station. These Depth-Plateaus correspond to density contrasts within the sediments and the underlying basement. These were then laterally merged with those from adjacent stations to form density interfaces. The results were validated with seismic and the litho-stratigraphy from well data which showed a good correlation with the tops of several sedimentary formations and intra-formational lithological boundaries. Ten density interfaces were mapped: Top Precambrian Basement, Top Nambeet Formation, Intra-Willara Interface, Top Acacia Sandstone, Top Willara Formation, Intra-Goldwyer Interface, Top Goldwyer Formation, Top Nita Formation, Intra-Tandalgoo Group Interface and Intra-Tandalgoo Group Interface.

The geological model built along the Test Profile from interpretation of the AGG data shows good correlation with the wells and seismic data.

This paper presents a 3D forward modelling algorithm with an adaptive finite-element method based on unstructured grids that when used with a circular scanning DC measurement technique can provide an indication of anisotropy in a layered earth. The accuracy of this algorithm is checked against 1D semi-analytical solutions for an arbitrarily anisotropic earth. This anisotropy produces a measurement paradox, results are dependent on the physical relationship between DC transmitter and receiver. To resolve this paradox, a circular scanning measurement technique has been suggested. Through analysing the response of typical anisotropic models, we study the characteristics of apparent resistivity related to the electrically anisotropic media and identification of underground electrical anisotropy. The results of numerical experiments shows the effectiveness of our algorithm and the analysis will be helpful to the interpretation of anisotropic DC resistivity data.

As the big-data age arrives, the efficiency of three dimensional inversions of potential field data can be paid enough attention by scholars. A new inversion method is considered to deal with the large potential field data with a fast rate of convergence. Hence, in this paper, a fast inversion method is researched. And the gravity data is used as an example of potential field data to test the efficiency of our inversion method. To achieve this aim, the study region will be divided into huge amounts of rectangular prisms with unknown constant physical properties of rock. The traditional smooth inversion method is the main principle, and a new Barzilai-Borwein iterative algorithm is applied to ensure the rapid rate of convergence of the inversion method. To compare the rate of convergence of the BB (Barzilai-Borwein) iterative algorithm, the iterative gradient descent algorithm and the iterative conjugate gradient algorithm are used as the compared algorithms. To test high efficiency of the new fast developed inversion method, the large synthetic gravity data are performed. The contrast analysis results can easily reflect the high efficiency of our new inversion method. The great practical value of our inversion method is expounded by a real gravity data. Therefore, the new inversion method may have a great influence on the potential field data inversion.

The focus of this study is to determine the geochemical properties of formation, produced and flowback fluids and correlate the findings to geochemical properties of different mineral groups. This analysis can be achieved by: (a) investigating the occurrence and abundance of trace elements and naturally occurring radioactive material associated with different mineral groups, (b) determining the geochemical composition of produced water associated with these compositionally different formations using a comparative study between hydrocarbon resources and individual basins, and (c) determining the mineral origin of these trace elements and NORM associated with produced water. The geochemical NORM and trace element composition associated with produced water depends on the characteristics of the original depositional environment, the composition of the source rock, post depositional genesis processes, type/grade of the hydrocarbon and the ability for these trace elements and NORM to become mobile. The USGS produced water database was used to compare the variation of geochemical properties of produced water between the various energy generating types and basins. This was achieved by developing a statistical analysis for each trace element and NORM and comparing the results between the various hydrocarbon types and basins. The results of this study illustrates; (a) that certain trace elements have an overall higher concentration within certain hydrocarbon resources, and (b) there is a correlation of trace elements concentration associated with compositionally different formation and is related to the formations unique mineralogy. The information contained in this study and studies on mechanism that impact fluid migration and well integrity will provide decision-makers the framework to develop a more detailed PWMP during the initial exploration phase that can be part of their requirements when applying to the land owners for an exploration licence.

A particularly difficult part of cricket umpi ring is judging whether the batsman has ‘nicked’ the ball on its way from the bowler to wicket keeper. If they have then the batsman is dismissed, if not, or if the batsman has hit his pad rather than the ball, then the batsmen remains in. Even with modern high-speed cameras discerning a nick by eye is virtually impossible so during international cricket matches the umpire is aided in their decision making by an audio recording. This can be inconclusive, however, if there is considerable other noise being made (usually by the crowd), and especially if there is the possibility that the batsman may have hit the ground or another part of his body or equipment. To a geophysicist the solution to this problem is obvious, attach three component vibration sensors to the bat, record the data, and then look for any impacts, and this is in-effect what we have done. The results are convincing, not only can we detect impacts but also the type of impact and even the position of the bat upon which the impact occurred. Not only is the data superior to audio recordings but can be obtained more easily and cheaply making its application to the lower levels of cricket possible.

Assessment of gullies is essential in understanding the effects soil erosion has on resource management, urban planning, agricultural productivity and local environmental conditions. Commonly, prediction of gully head cut retreat has been disregarded due to the inherent complexities; this study proposes a method of analysing data to interpret potential pathways of Gully retreat. Through the implementation of electrical geophysics (Electrical Resistivity Imaging & Frequency Domain Electromagnetics) surveys positioned uphill of existing gullies shallow conductor’s representative of Lateral Preferential Pathways (LPP) will be detected. ERI results detected conductors uphill of the head cut at varying distances showing resistivity values of 1 -40 Qm; these identified anomalous zones were confidently linked to form an LPP. Integrated geophysical datasets were generated allowing for interpreted traces of LPP to be drawn which are representative of the future pathway of head cut retreat. Through comparing currently existing gully assessment techniques it is suggested that a combination of geophysical prediction of LPP and LiDAR data is necessary for a complete understanding of existing gullies. Based on the results of this integration, informed and targeted management decisions can be developed to remediate current landforms and mitigate future gullying.

There has been recent focus placed on near surface groundwater and surface run-off flows as they have been attributed to erosion of consolidated and unconsolidated material resulting in incised surface channels referred to as gullies, which pose significant issues for agricultural productivity and local infrastructure (Beavis, 2000, Wu and Cheng, 2005). To effectively manage these erosional features through mitigation an understanding of the occurrence and future erosional pathways is required, although prediction is difficult when topographic variations are not obvious.

Local hydrological conditions will determine the nature of surface flows and groundwater movement including the infiltration depth, flow direction and rate of movement, although it is generally understood that water flows through physical or chemical channels known as preferential pathways (Clothier et al., 2007). Pathways develop within a medium due to the heterogeneities in the physical properties of the material that the water is flowing through.

The Southern Sydney Basin is a geological region of sub-horizontal conforming strata, including significant coal measures that have been mined for over 100 years. This apparently simple ‘layer-cake’ geology has overlooked many complexities associated with intrusions and a variety of geological structures. This over-simplification of geology has contributed to uncertainty in groundwater model outcomes, and impacts to surface hydrology and groundwater systems that have occurred at some sites. The aim of this study was to identify and characterize geological complexities within the Southern Sydney Basin with a particular focus on near surface groundwater and wetlands which could be sensitive to these direct or indirect disturbances.

An initial desk top review of existing drill-hole data, outcrop maps and typical spatial data was undertaken to highlight areas of possible structural inconsistency and areas with a high probability of faults or other structures such as monoclines. This data was then used in combination with field based geological mapping and high quality digital terrain modelling to assist the current development of a series of kinematic (geologically restored) cross-sections.

This has enabled the preliminary modelling of fault propagation folds associated with the inversion of growth faults, which will be important in the development of a framework to better identify and define the geometry of aquitards, associated with the Thirlmere Lakes and groundwater surface expression dependent ecosystems (swamps) over the Southern Sydney Basin. This greater understanding of the features around the Thirlmere Lakes area will lead to the development of a structural evolution model that further explains the incision of Blue Gum Creek and the development of Thirlmere Lakes within an entrenched meander.

Mt. Telomoyo is situated in Magelang Regency, about 400 kilometers from Jakarta. In the studied area, eight geothermal surface manifestations were found, consist of four hot springs and four cold springs. This research aims to identify upflow and outflow zones of geothermal area using compared value of geoindicator and tracer obtained from sampled of geothermal surface manifestations, and also to identify fluids flow of Mt. Telomoyo geothermal system. The method used in this research is to compile geoindicator comparison results, which are B/Li, Cl/B, Na/Ca, Cl/SO4, SO4/HCO3, and Na/K. Comparison results are then converted into geoindicator comparison maps. Fault and fracture is used to identify density of lineament, also direction of lineament where manifestation found. Afterward overlayed geoindicator maps and FFD maps is correlated to identify upflow/outflow zone and flow trend of geothermal fluid. The result of this research shows that the upflow zone in study area is located beneath Mt. Telomoyo, the upflow zone has high density of lineament. Furthermore, the outflow zones are found with two tendencies.The major trend of outflow is directed toward the western part of upflow zone, where geothermal manifestation APPD and APCU were found in ENE-WSW direction. The other outflow trend is directed toward the northeastern part of interpreted upflow zone, where geothermal manifestation APCD-1 and APCD-2 were found in NNW-SSE direction.