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Lithologically-constrained stochastic magnetotelluric inversion for imaging shallow conductors in geothermal fields

Tuesday, August 18, 2020
1300 AEST
1400 AEST

Presenter: Alberto Ardid Segura

Date: 18th August 2020

Time: 1300 AEST

Title: Lithologically-constrained stochastic magnetotelluric inversion for imaging shallow conductors in geothermal fields

 

Abstract:

Geothermal fields are usually explored by magnetotelluric (MT) surveys primarily to characterize a shallow conductor reflective of a conductive clay structure, commonly known as the clay cap. Standard deterministic MT inversions suffer from non-uniqueness and uncertainty, and the inclusion of useful lithological information is still limited. We develop a Bayesian 1D inversion method that integrates the electrical resistivity distribution from MT surveys with Methylene Blue (MeB) data, an indicator of conductive clay distribution in geothermal wells. The inversion seeks to infer under uncertainty the shallow conductor boundaries in geothermal fields. By incorporating borehole information, our inversion reduces non-uniqueness and then explicitly represents the irreducible uncertainty as estimated depth intervals for clay cap boundaries. This is particularly important when constraining the lower conductor boundary, as this feature is difficult to discriminate from the MT alone.

We apply the methodology to a set of 250 MT stations and 130 MeB profiles in the New Zealand Wāirakei geothermal field to estimate under uncertainty the conductor boundaries. Then, we compare the infer boundaries with the clay distribution, temperature logs and lithology from wells to estimate temperature gradients and conductive heat flux through the clay cap. By quantitative correlations among the different data sets, we present an unprecedented view into clay capping structures in high-temperature liquid dominated geothermal fields.

 

Bio:

Alberto is a MSc geophysicist who studied at the University of Chile, and is a current Doctoral candidate at the Geothermal Institute in the University of Auckland. His doctoral research is focussed on studying the electrical resistivity distribution in geothermal fields through Bayesian magnetotelluric inversions that allows assimilating data from different properties such as lithology and temperature, and quantifying uncertainty. Prior to that, Alberto’s research focused on shallow active and passive seismic exploration on geothermal systems. He also has industry experience mostly related to R+D in direct current, gravity and magnetic geophysical methods for mining and basin research.

To register, please go to this link: https://us02web.zoom.us/webinar/register/WN_qDrzV7GsQOKBtCnBApxeBQ

The Victoria Gold Mining & Exploration Forum

Thursday, August 27, 2020
0800
1700

https://www.informa.com.au/event/conference/victoria-gold-mining-explora...

The Victoria Gold Mining & Exploration Forum will be a digitally delivered event on the 27 August 2020. This event will examine the latest developments in gold mining and exploration in Victoria.

The Victorian gold industry is currently experiencing a renaissance, with authorities estimating that there may be approximately AU$150 billion worth of gold still waiting to be discovered in the State. Exploration and investment is ramping up across Victoria as the sector looks towards a reinvigorated future.

Topics will include:

  • Investment in Victoria
  • Market outlook
  • Government perspective
  • Case studies
  • New tenders
  • Community engagement

3rd Asia Pacific meeting on near surface geoscience and engineering

Wednesday, November 4, 2020
0800
1700

Welcome to the 3rd Asia Pacific Meeting on Near Surface Geoscience & Engineering

2 - 4 November 2020, Chiang Mai, Thailand

The European Association of Geoscientists & Engineers (EAGE) is excited to announce that the 3rd Asia Pacific Meeting On Near Surface Geoscience & Engineering event is coming to Chiang Mai, Thailand. We look forward to welcome all of you to join us in beautiful Thailand in November 2020.

Abstracts submission is now closed and papers' reviewing are on-going.

This event was originally planned on 20 - 22 April 2020 and postponed to 2 - 4 November 2020! 

 

Please click here to view the event.

Important Dates

Abstract Submission Deadline30 June 2020

Registration Open1 January 2020

SEGJ Seminar4 November 2020

ERT Short Course4 November 2020

3rd NSGE Conference2 - 3 November 2020

EAGE Geo-Quiz3 November 2020

Field Trip- Doi Inthanon National Park1 November 2020

3rd Asia Pacific meeting on near surface geoscience and engineering

Tuesday, November 3, 2020
0800
1700

Welcome to the 3rd Asia Pacific Meeting on Near Surface Geoscience & Engineering

2 - 4 November 2020, Chiang Mai, Thailand

The European Association of Geoscientists & Engineers (EAGE) is excited to announce that the 3rd Asia Pacific Meeting On Near Surface Geoscience & Engineering event is coming to Chiang Mai, Thailand. We look forward to welcome all of you to join us in beautiful Thailand in November 2020.

Abstracts submission is now closed and papers' reviewing are on-going.

This event was originally planned on 20 - 22 April 2020 and postponed to 2 - 4 November 2020! 

 

Please click here to view the event.

Important Dates

Abstract Submission Deadline30 June 2020

Registration Open1 January 2020

SEGJ Seminar4 November 2020

ERT Short Course4 November 2020

3rd NSGE Conference2 - 3 November 2020

EAGE Geo-Quiz3 November 2020

Field Trip- Doi Inthanon National Park1 November 2020

3rd Asia Pacific meeting on near surface geoscience and engineering

Monday, November 2, 2020
0800
1700

Welcome to the 3rd Asia Pacific Meeting on Near Surface Geoscience & Engineering

2 - 4 November 2020, Chiang Mai, Thailand

The European Association of Geoscientists & Engineers (EAGE) is excited to announce that the 3rd Asia Pacific Meeting On Near Surface Geoscience & Engineering event is coming to Chiang Mai, Thailand. We look forward to welcome all of you to join us in beautiful Thailand in November 2020.

Abstracts submission is now closed and papers' reviewing are on-going.

This event was originally planned on 20 - 22 April 2020 and postponed to 2 - 4 November 2020! 

 

Please click here to view the event.

Important Dates

Abstract Submission Deadline30 June 2020

Registration Open1 January 2020

SEGJ Seminar4 November 2020

ERT Short Course4 November 2020

3rd NSGE Conference2 - 3 November 2020

EAGE Geo-Quiz3 November 2020

Field Trip- Doi Inthanon National Park1 November 2020

Contemporary crustal stress pattern of Australia

Thursday, July 23, 2020
1200 (AWST)
1300 (AWST)

Title: Contemporary crustal stress pattern of Australia

 

Summary:

The present-day stress field of Australia has been the subject of great interest in the three past decades because it shows a variable pattern for the orientation of maximum horizontal stress (SHmax) that is not parallel to absolute plate motion. Analysis of in-situ stress data across Australia (in >20 sedimentary basins) reveals four major trends for the orientation of SHmax including NE-SW in northern, northwestern and northeastern Australia, E-W in southern half of Western Australia and South Australia, ENE-WSW in most parts of eastern Australia and NW-SE in southeastern Australia. In addition, the results reveal significant rotation of stress within various sedimentary basins due to the presence of different geological structures, including basement structures, faults, fractures and lithological contrasts. Understanding and predicting local stress perturbations has major implications for determining the most productive fractures in petroleum and geothermal systems, and for modelling the propagation direction and vertical height growth of induced hydraulic fractures in unconventional reservoirs.

Biography of the presenter:

Dr Mojtaba Rajabi is an ARC DECRA Fellow at the School of Earth and Environmental Sciences, University of Queensland. He has over 12 years of extensive experience in crustal stress analysis, reservoir geomechanics, geomechanical-numerical modelling and petrophysics. He graduated with a Ph.D. in Earth Sciences from the University of Adelaide in 2017. Dr Rajabi has worked on the geomechanical analyses of >30 sedimentary basins from across the world including Australia, New Zealand, Middle East, Mozambique, Iceland and Western Mediterranean. Since 2012, Dr Rajabi has worked on the Australian and World Stress Map projects. He has received >15 international awards and prizes for his research including the ARC-DECRA Award, the Australian SEG Early Achievement Award, EAGE Louis Cagniard Award, and the International Lithosphere Program’s Flinn-Hart Award.

Ten years in the wild (Redux)

Tuesday, July 7, 2020
1600 (AEST)
1700 (AEST)

The ASEG welcome you to join us on ZOOM on Tuesday 7 July, 4pm (AEST) for a talk by David Annetts from CSIRO.

 

Ten years in the wild (Redux)

An updated and expanded version of the AEGC presentation providing background to a CSIRO project that was placed in the public domain in 2009.  The talk offers lessons and guidance for others who would walk a similar path.

The use of open-source codes has become pervasive over the past 20 years but such codes are uncommon in minerals exploration. The P223 series of programs researching forward and inverse modelling of electromagnetic data was supported by CSIRO and six AMIRA consortia over 27 years and produced, amongst others, the codes, Airbeo, LeroiAir and Marco. This project concluded in 2008 and, after a two-year embargo, the code base, consisting of computer programs modelling different approximations of the earth for ground and airborne prospecting systems, was released to the public. We discuss reasons why codes have not been more widely adopted, and examine the evolution of some of the codes in research, academia and in industry as a guide to parties who would embark on a similar route.

David Annetts has been with CSIRO since 2007. A forward-modeller by inclination, he has researched the application of frequency and time-domain electromagnetic prospecting methods to marine CSEM, CO2 sequestration, uranium and groundwater exploration, and maintains an active interest in CSIRO’s Bayesian Lithological Inversion initiative.  He is also the current ASEG President.

Register Now: https://us02web.zoom.us/webinar/register/WN_wRoI_iXERlmmAA-wtXjHLw

 

After registering, you will receive a confirmation email containing information about joining the webinar.

Mentoring through change, a perspective

Tuesday, July 14, 2020
1700 (AEST)
1800 (AEST)

Please join us on Tuesday 14th July,  5pm (AEST) for a talk by Marina Costelloe from Geoscience Australia hosted by FedEx.

 

Mentoring through change, a perspective

Building on her experience as an ASEG President, STEM ambassador, and senior manager with Geoscience Australia, this talk is aimed at geophysicists at any stage in their career and will cover our shared leadership challenges, what we need to do more of, and less of, where to go to for help and how you can make the most of new opportunities for your workplace, your teams and for you in your own leadership sphere. There will be lots of time for questions and discussions.

Biography:

Marina Costelloe is the Director of the Onshore Seismic and Magnetotelluric Section within the Mineral Systems Branch at Geoscience Australia. Marina has worked in areas as diverse as mineral exploration, groundwater, critical infrastructure, earthquakes, and data science and contributed to international nuclear monitoring and space weather over the past 25 years. In 2018, Marina took on the role of President of the Australian Society of Exploration Geophysics (ASEG). Marina represents the Geology and Geography Cluster on the board of Science and Technology Australia and represents Australia on the Society of Exploration Geophysics Pacific Regional Affairs Committee.

Register Now: https://us02web.zoom.us/webinar/register/WN_quT25XVVTLGxJNTyy3XE_Q

 

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

 

Please bring your own drinks and nibbles.

ASEG Webinar: Coupling Surface Evolution and Mantle Dynamics: two examples of the interplay of Tectonics,

Wednesday, June 17, 2020
1800 (AEST)
1900 (AEST)

Please join us on Wednesday 17th June,  6pm (AEST) for a talk by Claire Mallard from USYD.

 

Coupling Surface Evolution and Mantle Dynamics: two examples of the interplay of Tectonics, Eustasy and Surface Processes

Over deep time, mantle flow-induced dynamic topography as well as plate tectonic evolution drive deposition moderated by higher-frequency fluctuations in climate and sea level. The effects of deep mantle convection and lithospheric deformation impact all the segment of the source to sink systems at different wavelengths and over various scales which remains poorly quantified. Field observations and numerical investigations suggest that the long-term stratigraphic record along continental margins contains essential clues on the interactions between dynamic topography and surface processes. However, it remains challenging to isolate the fingerprints of dynamic topography, lithospheric deformation, eustatic variation and climate change in the geological record.

In the first part of the talk, I will show you how we use a new numerical simulation package that couples the open-source surface evolution code Badlands (https://badlands.readthedocs.io/en/latest/) with lithospheric-scale thermo-mechanical models (https://uwgeodynamics.readthedocs.io/en/latest/) for unravelling the effect of rift obliquity on the distribution of facies and the evolution of stratigraphic architecture in syn-rift deposits.

The second part will focus on the integration of mantle convection simulation results into Badlands to quantify the impact of different timings and wavelengths of dynamic topography migration on the surface. I will present an example of the last 40 Ma evolution of the South African landscape.

 

The results suggest that our source-to-sink numerical workflow can be used to explore, in a systematic way, the interplay between dynamic topography and surface processes and can provide insights into recognizing the geomorphic and stratigraphic signals of dynamic topography in the geological record.

Register Now: https://us02web.zoom.us/webinar/register/WN_lf3ScLqiRCyGYll3gLcUnA

 

After registering, you will receive a confirmation email containing information about joining the webinar. Contact secretary@aseg.org.au if you have any questions.  

 

Please bring your own drinks and nibbles.

ACT Tech night - Computations methods in Geophysics

Wednesday, July 15, 2020
1630 (AEST)
1730 (AEST)

Date: Wednesday 15 July

Presenter: Indrajit G. Roy (PhD)

A link to the Zoom webinar will be shared closer to the event date.

Title: Computations methods in Geophysics

Abstract:

Mathematical derivatives, since their birth within calculus in the last quarter of seventeenth century, have been occupying a most important place in almost every sphere of science.  They are fundamental to geophysical modelling and particularly potential field data analysis, from data presentation through to quantitative interpretation. But the challenges of robust and precise estimation of derivatives along with their implementation are many. This presentation will review some of those challenges, how to minimize errors and provide insight into many of their applications.

 

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