WA

Teena Zn Prospect - New Insights for Geophysical Discovery of Shale-hosted Zinc Deposits
Darren Hunt 
(Senior Project Geophysicist - Teck)

Teena is a Paleoproterozoic stratiform Zn-Pb deposit located 8 kilometres west of the McArthur River Zn-Pb Mine, NT.  Higher grade mineralization was drilled by Teck in 2013, and represents the most significant SHMS-style discovery in Australia since the early 1990’s.  While the style of mineralization is similar to McArthur river (HYC) Mine, Teena lies beneath 600 to 1000m of siliciclastic and calcareous sediments and is completely blind.  Thus, the system gives the explorationist  valuable insights into the challenge of exploring for blind SHMS deposits, which often present as challenging targets for geophysical detection.  This talk will present physical properties data in the context of the mineralogy and stratigraphic host and discuss the geophysical methodologies applied to at Teena and the subsequent toolkit developed for the detection of deeply buried systems using Teena datasets as examples.

*REGISTRATIONS REQUIRED* by Friday 12^th April

Exploring the Triassic Oil Potential on the North West Shelf, Australia

Claudia Valenti (Carnarvon Petroleum)

The exploration history of the North West Shelf suggests that the Australian petroleum systems are predominantly gas prone, typically found beneath the mid-Cretaceous regional seal.

Carnarvon Petroleum regional and local seismic mapping, in conjunction with exploration drilling results, indicates that the Triassic has three oil prone petroleum systems, the Early, Middle and Late Triassic.

Fundamental to understanding the areas where these three petroleum systems will work is a thorough understanding of palaeogeographies, palaeoenvironments and stratigraphy. Carnarvon believes the petroleum systems have a distinct palaeogeographic distribution and are not ubiquitous source rock/reservoir horizons across the North West Shelf.

Various laboratory analysis, sedimentology, seismic mapping, seismic facies work have contributed to the identification of the most encouraging areas to explore.

Additionally, the proximity of the Triassic geology of the North West Shelf to SE Asia Triassic geology, with their similar depositional setting, prior to Gondwana break-up, adds credence to the proposed theories. Examples of the early, middle and late Triassic oil petroleum systems will be illustrated and identified in some of the major basins on the NW Shelf.

Groundwater Throughflow and Seawater Intrusion in High Quality Coastal Aquifers
Alex Costall (PhD Student - Curtin University)

This last year has taken me into the wonderful world of karstic aquifers, numerical groundwater flow - and solute transport - modelling. A ‘karst’ refers to terrain with distinctive structures formed from highly soluble rocks, such as limestone, dolomites, gypsums, etc. Exposure to flowing groundwater causes the rock matrix to dissolve, which can greatly affect the flow of groundwater. Caves, conduits, and fractures all present high-permeability pathways for groundwater to travel. Some of the highest quality coastal groundwater reserves around the world exist as extensive karstic aquifer systems. At coastal margins, the invisible and ever-looming seawater interface threatens fresh groundwater resources.  As the changing climate affects groundwater recharge and growing world population continues to rely on these aquifers for drinkable groundwater, the risk of contamination has implications for millions of peoples worldwide. 

Geophysical exploration methods offer unparalleled access to subsurface information, but it is not without flaws. Resistivity imaging is commonly used, but rarely with time-lapse investigation nor optimal acquisition/inversion strategy in mind. Numerical solute transport modelling has potential to aid our understanding, and define the limitations, of the both geophysical and conventional sampling methodology. Outcomes from this research aim to improve groundwater monitoring practices and numerical modelling outcomes with regard to the seawater interface. These outcomes will ultimately aid groundwater management decisions and help to preserve our fresh water resources for future generations.

Alex is a PhD student at Curtin University, Department of Exploration Geophysics, specializing in near-surface hydrogeophysical problems. He completed a Bachelor of Science (Geophysics) with first-class honours in 2014, and works part-time within the geophysics department as a research assistant and laboratory demonstrator. Alex’s research interests include groundwater and solute transport modelling, cooperative geophysical modelling, and exploration with ground penetrating radar and electrical resistivity.

 
Register your attendance by emailing wapresident@aseg.org.au.

*REGISTRATIONS REQUIRED* by Friday 12^th April
 
Sometimes it pays to be cheap – Compressive time-lapse seismic data acquisition

Felix Herrmann (SEG Distinguished Lecturer)

During these times of sustained low oil prices, it is essential to look for new innovative ways to collect (time-lapse) seismic data at reduced costs and preferably also at reduced environmental impact. By now, there is an increasing body of corroborating evidence — whether these are simulated case studies or actual acquisitions on land and marine — that seismic acquisition based on the principles of compressive sensing delivers on this premise by removing the need to acquire replicated dense surveys. Up to ten-fold increases in acquisition efficiency have been reported by industry while there are indications that this breakthrough is only the beginning of a paradigm shift where full-azimuth time-lapse processing will become a reality. To familiarize the audience with this new technology, I will first describe the basics of compressive sensing, how it relates to missing-trace interpolation and simultaneous source acquisition, followed by how this technology is driving innovations in full-azimuth (time-lapse) acquisition, yielding high-fidelity data with a high degree of repeatability and at a fraction of the costs.
 
Felix J. Herrmann graduated from Delft University of Technology in 1992 and received in 1997 a Ph.D. in engineering physics (DELPHI Consortium) from that same institution. After research positions at Stanford University and the Massachusetts Institute of Technology (Earth Resources Laboratory), he joined the faculty of the University of British Columbia in 2002 where he is now affiliate professor. Since 2017, he is cross-appointed at the Schools of Earth & Atmospheric Sciences, Computational Science & Engineering, and Electrical & Computer Engineering of the Georgia Institute of Technology. His research program spans several areas of computational exploration seismology including economic and low-environmental impact (time-lapse) acquisition with compressive sensing, data processing, and wave-equation-based imaging and inversion. He was among the first to recognize the importance of curvelet transforms, compressive sensing, and large-scale (convex) optimization addressing problems involving simultaneously acquired/blended (time-lapse) data with surface-related multiples. He developed curvelet-based denoising and matched filtering methods that are now widely used by industry. He also made several contributions to full-waveform inversion and (least-squares) reverse-time migration by introducing concepts from stochastic and constrained optimization designed to produce high-fidelity results at lower costs. More recently, he has been involved in developing rank minimization techniques for seismic data acquisition, in the development of a domain-specific language for finite differences called Devito, and in the application of deep convolutional neural nets to seismic data processing and inversion. To drive innovations within industry, he started in 2004 SINBAD, a research consortium responsible for several major breakthroughs resulting in tangible efficiency improvements in industrial data acquisition and full-waveform inversion. At Georgia Tech, he vows to continue these activities by setting up a new research consortium with a focus on machine learning. He serves as deputy editor for Geophysical Prospecting and is a Georgia Research Alliance eminent scholar.

Register your attendance by emailing wapresident@aseg.org.au.

Proudly supported by: PGS and Equinor

Our Evolving View of Time-Lapse Seismic Monitoring: 20 years of the same old Teal South data

Prof Wayne Pennington

The first ocean-bottom time-lapse seismic studies for reservoir monitoring were conducted at Teal South in the Gulf of Mexico.  The data from this field, including one legacy streamer survey and two post-production ocean-bottom surveys have been used repeatedly to demonstrate new aspects of analysis and interpretation. This seminar will walk through that history, since 1998, with examples from recent publications.

Biography

Wayne Pennington recently retired from the position of Dean of Engineering at Michigan Technological University, and is visiting Curtin University as a Senior Fulbright Scholar through May 2019.  He has spent his career in academics, industry, and (for one year) in government service, and has served as President of the American Geosciences Institute (an umbrella organization for over 50 geoscience societies) and as Vice-President of the Society of Exploration Geophysicists.

2019 Pacific South Honorary Lecturer Tour

Seismic attenuation, dispersion, and anisotropy in porous rocks: Mechanisms and Models
Boris Gurevich, Curtin University and CSIRO, Perth, Australia

Understanding and modeling of attenuation of elastic waves in fluid-saturated rocks is important for a range of geophysical technologies that utilize seismic, acoustic, or ultrasonic amplitudes. A major cause of elastic wave attenuation is viscous dissipation due to the flow of the pore fluid induced by the passing wave. Wave-induced fluid flow occurs as a passing wave creates local pressure gradients within the fluid phase and the resulting fluid flow is accompanied with internal friction until the pore pressure is equilibrated. The fluid flow can take place on various length scales: for example, from compliant fractures into the equant pores (so-called squirt flow), or between mesoscopic heterogeneities like fluid patches in partially saturated rocks. A common feature of these mechanisms is heterogeneity of the pore space, such as fractures, compliant grain contacts, or fluid patches. Using theoretical calculations and experimental data, we will explore how this heterogeneity affects attenuation, dispersion, and anisotropy of porous rocks. I will outline a consistent theoretical approach that quantifies these phenomena and discuss rigorous bounds for attenuation and dispersion.

Time table

Biography

Boris Gurevich has an MSc in geophysics from Moscow State University (1976) and a PhD from Institute of Geosystems, Moscow, Russia (1988), where he began his research career (1981–1994). In 1995–2000 he was a research scientist at the Geophysical Institute of Israel, where he focused mainly on diffraction imaging problems. Since 2001, he has been a professor of geophysics at Curtin University and advisor to CSIRO (Perth, Western Australia). At Curtin he has served as Head of Department of Exploration Geophysics (2010–2015) and since 2004 as director of the Curtin Reservoir Geophysics Consortium. He has served on editorial boards of Geophysics, Journal of Seismic Exploration, and Wave Motion. He is a Fellow of the Institute of Physics and has more than 100 journal publications in the areas of rock physics, poroelasticity, seismic theory, modeling, imaging, and monitoring of CO₂ geosequestration. His research achievements include development of advanced theoretical models of seismic attenuation and dispersion in heterogeneous porous rocks.

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