ASEG Extended Abstracts最新文献

{"title":"Gippsland Basin 3D forward modelling in Badlands","authors":"Xue-jun Yang, G. Smith","doi":"10.1080/22020586.2019.12073104","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073104","url":null,"abstract":"Summary The Gippsland basin geological history is modelled using the Badlands software constrained by a realistic 3D structural and stratigraphic model built in Petrel. The aim is to assess and calibrate the theoretical tectonic and sedimentary models using empirical data for a rift basin. The theoretical models are used to assess and measure the relative effect of significant variables for sedimentary basins, including climate, extension, subsidence, uplift, erosion and sedimentation. The modelling results indicate several insights for the Gippsland Basin. The initial paleo-topography at ~145 Ma was an extensive highland area. The Early Cretaceous paleo-environment was intracratonic, with sediment transport from east to west, and at some stage included an inland sea. The Mid Cretaceous uplift caused emergence of the entire basin, substantial regional erosion and changed the basin architecture. Subsidence associated with Tasman Sea rifting formed the Central Deep and flipped the fluvial paleo-drainage system towards the east. Latrobe Group sediments filled the basin being progressively transgressed by rising sea level to flood most areas by the Oligocene. The models simulate the progradation of the carbonate shelf sediments, sub-marine channels and anticlines over the basin since then.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89841735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Smart stitching: adding lateral priors to ensemble inversions as a post-processing step","authors":"G. Visser","doi":"10.1080/22020586.2019.12073075","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073075","url":null,"abstract":"Summary The last decade has seen extensive development of Bayesian geophysical inversion methods which produce ensembles of models as outputs. Many of these are limited to producing 1D or very simple and narrow models. It is well established that tying such narrow inversions together using lateral priors can significantly improve inversion results. Such laterally constrained inversion can, however, be complicated to code and add computational overhead. For this reason, available Bayesian geophysical inversion codes often do not include lateral priors as an option. I introduce a simple and easy to use method that allows lateral priors to be added to Bayesian ensemble inversion results as a post-processing step. This method has the potential to extend the use of many existing inversion codes and results. It can significantly reduce computational costs when practitioners want to experiment with different lateral priors. The method is demonstrated using synthetic magnetotelluric data and VTEM data from Cloncurry in Queensland.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72667546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triassic petroleum systems on the central North West Shelf – Learnings from the greater Phoenix area seismic mapping and geochemical studies","authors":"N. Rollet, E. Grosjean, D. Edwards, R. Kempton, D. Nguyen, S. Abbott, C. Orlov, G. Bernardel, C. Nicholson","doi":"10.1080/22020586.2019.12073047","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073047","url":null,"abstract":"Summary The greater Phoenix area in the Bedout Sub-basin has experienced recent exploration success on Australia’s North West Shelf (NWS). Oil and gas discoveries in the Triassic reservoirs of the Keraudren Formation and Locker Shale have revived interest in mapping the distribution and lateral facies variation of the Triassic succession from the Bedout Sub-basin into the adjacent underexplored Beagle and Rowley sub-basins. This multi-disciplinary study integrating structural architecture, sequence stratigraphy, paleogeography and geochemistry has mapped the spatial and temporal distributions of Triassic source rocks on the central NWS. The Lower-Middle Triassic paleogeography is dominated by a deltaic system building from the Bedout Sub-basin into the Beagle Sub-basin. The oil sourced and reservoired within the Lower‒Middle Triassic sequences at Phoenix South 1 is unique to the Bedout Sub-basin, compared to other oils along the NWS. Its mixed landplant and algal biomarker signature is most likely sourced locally by fluvial-deltaic mudstones within the TR10‒ TR14 or TR15 sequences and represents a new petroleum system on the NWS. A Middle Triassic marine incursion is recorded in the Bedout Sub-basin with the development of a carbonate platform while in the Rowley Sub-basin, volcanics have been penetrated at the top of the thick Lower‒Middle Triassic sediment package. The Late Triassic paleogeographic map suggests a carbonate environment in the Rowley Sub-basin distinct to the clastic-dominated fluvial-deltaic environment in the Beagle Sub-basin. This information combined with results of well-based geochemical analyses highlights the potential for hydrocarbon generation within the Upper Triassic in these sub-basins.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79079792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity-based data reduction of large 3D DC/IP surveys","authors":"Sarah G. R. Devriese, R. Ellis, K. Witherly","doi":"10.1080/22020586.2019.12073229","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073229","url":null,"abstract":"Summary In this paper, we present an algorithm based on the sensitivity of the data to the model space to reduce the large amount of data commonly collected during 3D DC/IP surveys to only those most relevant and important to the model space. The sensitivity-based data reduction (SBDR) algorithm is demonstrated using both synthetic and field data examples. The results indicate that the SBDR recovered models are valid solutions to the full inversion problem but require a fraction of the computation time and resources, providing a geologic solution in a much shorter time than required to solve the full inversion problem.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79289921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Update on the geophysical expression of the Abra sedimentary replacement Pb-Ag-Cu-Au deposit, Western Australia","authors":"D. Stannard, J. Meyers, E. Turner, A. Scopel","doi":"10.1080/22020586.2019.12073204","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073204","url":null,"abstract":"Summary The Abra sedimentary replacement Pb-Ag-Cu-Au deposit is located in the Paleoproterozoic Edmund Basin, 900km NNE of Perth. Mineralisation at Abra has no surface expression and the deposit was discovered in 1981 by drill testing coincident magnetic and gravity anomaly highs. The deposit is hosted within siliciclastic and carbonate deposits of the Edmund Group and consists of a stratabound apron of lower grade Pb-Ag-Ba mineralisation in a laminated iron oxide and barite altered siltstone unit that overlies a funnel shaped feeder zone of chlorite altered, brecciated and veined carbonaceous siltstone containing high-grade Pb-Ag in the core, transitioning to Pb-Cu and Cu-Au at depth. As at December 2018, the Abra deposit remains unmined and has an estimated resource of 37.4Mt at 7.5% Pb and 18g/t Ag. Mutton and McInerney (1987) and McInerney et al. (1994) described the geophysical expression of Abra, and recent geophysical survey results are presented here. Abra is characterised by discrete anomaly responses in magnetic, gravity and TDEM survey data. A +450nT magnetic anomaly is observed in ground and airborne magnetic data, which is caused by magnetite within the lower part of the stratabound zone. Dense galena, barite and iron oxide mineralisation in the stratabound zone, and galena in the feeder zone, is surrounded by low-density sedimentary host rock, resulting in a +1mGal gravity anomaly. TDEM surveys have resolved massive sulphide mineralisation as EM conductors, and petrophysical testing on core samples show this is mostly caused by galena. Inverted AMT-MT data sections resolved the deposit halo as a conductive anomaly. ZTEM data failed to resolve a distinct anomaly response. DDIP surveying failed to resolve a chargeable anomaly coincident to known high-grade mineralisation, despite significant disseminated sulphide mineralisation occurring within the deposit. An IP chargeability anomaly observed on the southern side of the deposit is thought to be associated with an alteration zone and low-grade disseminated sulphide mineralisation in a fault zone. A 2D seismic reflection survey line resolved the deposit envelope as strong seismic reflectors surrounded by a seismically bland zone, and this is related to the significant density contrast between the high-density stratabound mineralisation in contact with low-density sedimentary host rocks, as the mineralisation and host rock have similar seismic velocities. Passive seismic HVSR surveying resolved the top of Abra as a subtle HVSR response below a flat impedance contrast horizon interpreted as weathered siltstone over diagenetic cemented siltstone.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75855090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of multi-element geochemistry in the weathered environment: Controls, considerations and implications for exploration","authors":"F. Best, Matthew Readford, K. Walcott","doi":"10.1080/22020586.2019.12073224","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073224","url":null,"abstract":"Summary Understanding the mobility of individual elements in the oxidised environment is important for the accurate interpretation of geochemical data from regolith and weathered bedrock samples. In the weathered environment, immobile element geochemistry can reflect primary lithological and in situ mineralisation signatures, whereas mobile elements can help establish the degree and extent of weathering. Three exploration case studies are presented here to demonstrate the application of multielement geochemistry in the weathered environment: An example from the Shorty Creek Project, Alaska (Freegold Ventures), highlights the importance of reviewing and understanding pathfinder elements in soil, weathered bedrock and fresh basement. Here, commodity elements Cu and Zn are highly mobile and relatively depleted in the soils and weathered zone over Cu-Au mineralisation, whereas Au, As, Bi and Sb are less mobile and highly anomalous in the oxidised bedrock and associated soils. The Hermosa Deposit, Arizona (South32), where downhole geochemistry can help map the oxide-fresh rock boundary at the deposit scale. Subtle depletion in mobile elements allows the weathered zone to be identified in altered rhyolites, and Zn:S and Pb:S ratios in the mineralised zone helps distinguish Zn and Pb oxides from Zn and Pb sulphides. A review of residual soils over a Ni-Cu-PGE prospect in Northern Queensland, where immobile elements are reliable discriminants of primary lithologies in highly weathered environments. Zirconium, Y, Th and Nb can be used to distinguish felsic from mafic bedrock, and variations in Cr, V, Al, Fe and Sc in soils confidently identify blind, compositionally distinct mafic-ultramafic bodies. This paper also highlights the importance of collecting high quality, multi-element geochemistry with low detection limits at every stage of exploration.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75064847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Supporting data-driven exploration in NSW","authors":"Keith Gates","doi":"10.1080/22020586.2019.12073240","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073240","url":null,"abstract":"Summary NSW legislative changes in 2016 mean that from 1 June 2021, confidential mineral exploration company reports will become open file 5 years after submission. This will result in a large amount of previously confidential data being released on 1 June 2021. In conjunction with the data release, substantial work is being undertaken to improve the quality, accessibility and usability of the datasets. To provide the most functional regional scale geochemical datasets possible, the usability of the datasets must be assessed by following a standard workflow of data validation > exploratory data analysis (EDA) > normalisation > interpolation. Due to the large size of the datasets, programmatical solutions that expedite the validation and EDA processes are necessary. This presentation will give examples of methods used to condition the NSW geochemical data. An innovative data normalisation process will also be demonstrated, addressing the complexity of dealing with spatially overlapping and varied sample methods. An interpolation process that is suitable for use on large volume, large-scale datasets will also be demonstrated.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75072998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Augmenting 1D conductivity depth sections to include information pertaining to 2D/3D conductors","authors":"M. Combrinck","doi":"10.1080/22020586.2019.12072981","DOIUrl":"https://doi.org/10.1080/22020586.2019.12072981","url":null,"abstract":"Summary Conductivity depth data presentations derived using 1D approximations have become a very popular way to present airborne electromagnetic (AEM) data. While data profiles and a single error limit per station can accompany these presentations there are more information contained in data. This work proposes some ideas for augmenting 1D derived data presentations to highlight two and three-dimensional conductors as well as more detailed error level indication. The 1D conductivity depth algorithm used is an extended version of the S-layer differential transform. The depths calculated with the transform is used also present decay constant values corrected for conductive background responses. Fraser filtered X-component data are used to indicate structural complexity and data fit error levels are used to grey out areas on the depth section presentations where the results are less reliable. To demonstrate these ideas a line of Xcite data over the Abra deposit in Western Australia is analysed. The augmentations add valuable information to the conductivity depth section in the sense of drawing attention the where the 1D assumptions are not valid and should encourage interpreters to pursue 2D or 3D modelling techniques for successfully mapping the ore deposit.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75883459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"IPEx: A lower-cost superior reconnaissance RES/IP/MT survey","authors":"S. Boucher","doi":"10.1080/22020586.2019.12072984","DOIUrl":"https://doi.org/10.1080/22020586.2019.12072984","url":null,"abstract":"Summary This paper presents a technique derived from the full MIMDAS RES/IP/MT survey called IPEx. It offers a more cost-effective, enhanced reconnaissance IP investigation in areas of post-mineral cover, ensuring that a minimumsized predefined chargeable body would not be missed. The MIMDAS system is ideal for its capability to measure very low signals, due to the enhanced telluric correction, especially in caliche-covered areas. A total of four lines were surveyed with IPEx, and substantial anomalies were found, where some in-fill/detailing has been executed. IPEx takes approximately half to two thirds of the normal MIMDAS survey time, making it a lower-cost superior reconnaissance RES/IP/MT survey tool.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74106848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Bight Basin, Evolution & Prospectivity III; FE modelling","authors":"R. Farrington, K. Hill, J. Cunneen, R. Beucher, L. Moresi","doi":"10.1080/22020586.2019.12073226","DOIUrl":"https://doi.org/10.1080/22020586.2019.12073226","url":null,"abstract":"Summary This paper outlines a Finite Element modelling workflow using the software package ‘Underworld’ that is applied to sedimentary basin undergoing multiple rifting events. The evolution of the resulting strain rate, viscosity structure, temperature field, and sedimentary structures can be tracked. Application to the Ceduna Sub-basin is discussed.","PeriodicalId":8502,"journal":{"name":"ASEG Extended Abstracts","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73804447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}