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ACT - A new magnetic tensor approach to mapping magnetic rock properties and cover depth using AI

Tuesday, November 12, 2019
1630
1800

Title : A new magnetic tensor approach to mapping magnetic rock properties and cover depth using AI

Date : 12th of November, Drinks and food from 4:30 for a 5pm start.

Presenter : David Pratt, Manager Research & Development, Tensor Research.

Location : Geoscience Australia, Scrivener Room.

 

Abstract

The presentation covers the use of an expert system AI method applied to magnetic gradient tensor data for mapping depth of cover and formation properties as a constrained 3D geological problem. The constraint takes advantage of an often, overlooked fact that the basement unconformity surface dominates the magnetic response measured in conventional airborne magnetic surveys. This dominance allows us to recover the rock properties and depth of the formations that are truncated by the basement unconformity. Recovery of rock property information from airborne surveys gives us the opportunity to look at old data with new eyes for the stones that were never turned.

Exploration under cover is very important to the discovery of new resources to replace existing mines as old resources are depleted. The magnetic method has evolved into an important tool for understanding the subsurface geology and location of favourable environments suitable for the emplacement of a broad range of economic minerals. A large part of the value is derived from qualitative interpretation of the spatial relationships and mapping of the inferred geology. However, much valuable information about the rock properties and cover depth is never recovered from the survey data.

Advances in the understanding of geologically constrained processing of the survey data along with rapid improvements in data quality and reduced line spacing promises to deliver higher resolution information on magnetic properties. Improved estimation of magnetic susceptibility provides guidance on the possible range of rock types associated with individual magnetic anomalies.

Magnetic remanence, often considered as inconvenient for interpretation, is an important indicator of a geological event, which in some cases may be associated with a mineralising process. We can now recover subtle magnetisation information indicative of magnetic remanence that is essentially invisible in a magnetic image. In many cases, subtle remanence events are lost in the low contrast blue areas of an image, yet these may contain clues to mineralising events.

About the speaker:

Manager Research & Development, Tensor Research. He holds a B.Sc. (Hons) and M.Sc. from the University of Sydney in Geology and Geophysics and a Ph.D. in Physics from the University of Newcastle. His early career started with the NSW Geological Survey, and then he worked as a geophysical consultant until 1984 when he co-founded Encom Technology. He was Managing Director from 2001 until it was acquired by Pitney Bowes Software in 2007. In 2010 he started Tensor Research with two colleagues to focus on advanced potential field research. He received the ASEG’s Grahame Sands Award in 2010 and Laric Hawkins Award in 2013.

SEG DISC 2019: Physics and Mechanics of Rocks: A Practical Approach

Thursday, August 29, 2019
09:00
17:00

 See here for more details adn registration: https://seg.org/Education/Courses/DISC/2019-DISC-Manika-Prasad

Intended Audience

  • Seismic imagers and interpreters who want to learn how fluids, stress, and other environmental effects change seismic signatures
  • Geophysicists who wish to derive rock properties and constrain well-to-seismic ties
  • Geologists and sedimentologists looking to develop predictive models of sedimentary environments and stratigraphic events
  • Reservoir engineers to build porosity, permeability, and fluid coverage models for reservoir simulations using 3D and 4D seismic data
  • Basin modelers and completions engineers to evaluate stresses from well log and seismic data
  • Geoscientists doing formation evaluation and well logging interpretations
  • Basin managers and team leaders who wish to evaluate the accuracy of predictions and understand risk and errors in models

Prerequisites (Knowledge/Experience/Education Required)

Attendees should have an understanding of basic rock properties such as porosity, permeability, sediment compositions and depositions, and structural geology. It will be helpful to have familiarity, but not necessarily expertise, in seismic properties. The accompanying textbook will include mathematical details, data and problem solutions for mineral modulus calculations, rock stiffness calculations for textural symmetries, velocity binning in flow zones, pore stiffness, and Gassmann fluid substitution. The lecture will focus on fundamental rock physics principles, applications, and analysis of results.

Course Outline

The course is organized into two main sections: Section I. Rock Physics Fundamentals (introductory section) and II. Advanced Topics in Rock Physics (application section):

Rock physics fundamentals

In this section, I will:

  • Review fundamental principles underlying rock physics, and rock properties
  • Investigate the effects of fluids on rock properties
  • Derive basic rock physics correlations and explain why and how they work
  • Review rock properties that can be mapped with remote sensing

Advanced Topics in Rock Physics

In this section, the student is introduced to:

  • Poroelasticity
  • Attenuation and dispersion
  • Geomechanics
  • Complex electrical conductivity and permeability
  • Investigate the causes for complications and deviations from basic correlations
  • Examine existing empirical and theoretical models
  • Discuss selected case studies in rock physics

Learner Outcomes

On completion of the course, the learner should be able to

  • Describe and explain the applications of rock physics for reservoir characterization, formation evaluation, and field monitoring
  • Identify and evaluate existing and potential technologies applicable to rocks physics and rock mechanics for reservoir/formation studies
  • Identify, list, and describe the physical properties of rock, and relate these properties to the mechanical behavior of rocks
  • interpret and predict the effect of mineral properties (e.g. clay minerals) on the load-bearing capacity and strength of rocks
  • Integrate and model elastic wave propagation, electrical conductivity, and fluid flow in rocks
  • Evaluate and assess errors in experimental data, uncertainty, and the value of theoretical models
  • Develop expertise in rock physics interpretations of seismic and electrical conductivity to identify fluids and quantify saturations
  • Gather key strengths in rock physics interpretations by developing a broad understanding of existing or potential technology transfers between engineering and earth science fields that relate rock physics to reservoir geophysics and reservoir engineering
  • Gain knowledge and expertise to understand physical and mechanical behavior of rocks through examples of stress-dependent changes in strains, seismic velocity, electrical conductivity, and pore structure
  • Interpret rock physics and rock mechanics data and model elastic wave propagation, electrical conductivity, and fluid flow in rocks
  • Assess errors in experimental data, assess the uncertainty and the value of rock physics models
  • These learning objectives will allow geoscientists and engineers to:
  • Distinguish major trends in and control factors for velocity and impedance changes in the subsurface
  • Describe and evaluate velocity and impedance data for changes in fluids and stresses
  • Apply basic rock physics techniques to evaluate reservoirs
  • Identify and select the best practice workflows when using rock physics for seismic interpretations
  • Analyze complex conductivity data to interpret reservoir properties

 

Abstract

Rock physics is an interdisciplinary branch of geophysics that explains geophysical remote sensing data, such as seismic wave velocities and electrical conductivity, in the context of mineralogy, fluid content, and environmental conditions. Thus, rock physics interpretations often require inputs from physics, geology, chemistry, chemical engineering, and other fields. For example, seismic waves travel faster in cemented rocks than in loose sediments. Since the physical behavior of rocks controls their seismic response, rock physics brings key knowledge that helps with the interpretation of rock properties such as porosity, permeability, texture, and pressure. Rock physics combines indirect geophysical data (such as seismic impedance, sonic log velocities, and laboratory measurements) with petrophysical information about porosity, fluid type, and saturation for use in reservoir characterization, evaluation, and monitoring. Typically, rock physics is used by petroleum engineers doing reservoir simulations, geologists evaluating over-pressures and making basin models, and anyone doing a monitoring survey to map fluids from 4D seismic. For all such purposes, an understanding of wave propagation is required to relate seismic properties (e.g. velocity and attenuation) to the physical properties of rocks and to evaluate seismic data in terms of subsurface petrophysical parameters.  For example, an application of rock physics is seen in 4D seismic data (i.e. repeated seismic data acquired from the same field), where fluid saturation changes are evaluated from changes in velocity using fluid substitution models. Another rock physics application is to understand and predict the effect of clay minerals on the load-bearing capacity and strength of rocks using fundamental knowledge about the properties of clay minerals (e.g. CEC, surface area, dispersability, charge, sorption, plasticity, etc.), the clay water content, as well as the effects of their distribution within the rock. Thus, an effective prediction of rock properties from indirect measurements requires a solid understanding of the physical behavior of rocks under in situ conditions of pore and confining pressures and fluid saturations.

During this one-day short course, I will provide the earth scientist and engineer with a foundation in rock physics to describe the physical processes that govern the response of rocks to the external stresses essential for reservoir characterization. The course will also offer practical guidance to help better analyze existing data. A major goal of this course is to offer practical instruction and provide working knowledge in the areas of rock physics and rock mechanics for rock characterization.

SEG Distinguished Lecturer Tour: Boris Gurevich

Wednesday, March 13, 2019
17:30
19:00

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

Date State Venue Start time Contact
13 March WA Celtic Club, 2nd floor, 48 Ord Street, West Perth 18:00 Heather Tompkins
15 March ACT Geoscience Australia 12:30 James Goodwin
19 March Qld XXXX brewery (Alehouse), Black Street, Milton 17:30 Ron Palmer
20 March NSW 95-99 York St 18:00 Mark Lackie
21 March Vic The Kelvin Club 18:00 Seda Rouxel
25 March SA/NT Coopers Alehouse 18:00 Kate Robertson
27 March Tas Geology Lecture Theatre, University of Tasmania 13:00 Mark Duffett

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.

Sponsors

Platinum sponsors
Gold sponsor

2018 SEG/AAPG Distinguished Lecturer: Satish Singh

Tuesday, August 7, 2018
17:30
19:00

Seismic Full Waveform Inversion for Fundamental Scientific and Industrial Problems.

Seismic waveform inversion is a powerful method used to quantify the elastic property of the subsurface. Although the development of seismic waveform inversion started in the early 1980s and was applied to solve scientific problems, it became popular in industry only about 15 years ago. One of the key elements in the success of seismic waveform inversion has been the increase of the acquisition of long offset seismic data from 3 km in the early 1990s to more than 15 km today. Not only did long offset data provide refraction arrivals, but it also allowed recording of wide-angle reflections, including critical angles, providing unique information about the subsurface geology.

In this talk, I will elaborate on the early development of the seismic full waveform inversion (FWI) and its application to solve fundamental scientific problems. The first big success of FWI was its application to gas hydrate reflections, also known as bottom simulating reflection (BSR), which showed that the
BSRs are mainly due the presence of a small amount of free methane gas, not a large amount of hydrates stored above the BSR, and hence the total amount of methane stored in marine sediments should be much less than previously estimated. A second major success of FWI was its application to quantify the characteristics of the axial melt lens observed beneath ocean spreading centers. The seismic full waveform inversion results show that one can distinguish between pure melt and partially molten mush within a 50 m thick melt lens, allowing to link the melt delivery from the mantle with the hydrothermal circulation on the seafloor. The application of full waveform inversion to spreading center problems has become an important area of research.

Unlike in sedimentary environment, the seafloor in general scientific environment could be very rough and water depth could be deep, making it very difficult to use the conventional method of background velocity estimation. To address this issue, the surface seismic data could be downward continued to the seafloor, as if both streamer and sources were placed on the seafloor, similar to land geometry. This method allows to bring the refraction starting from zero offset to far offset, which is extremely useful for full waveform inversion of first arrivals. The downward continuation also allows to reduce the seafloor diffraction, increase the moveout of reflection arrivals, and enhance wide-angle reflections, all important for seismic full waveform inversion. The application of a combination of downward continuation and FWI has allowed to quantify gas anomalies in sedimentary basins and fluids at subduction fronts. The waveform inversion also has been used to monitor CO 2 sequestration.

I will explain the intricacy of FWI, based on the physics of waves, specifically the role of amplitudes and converted waves in addressing fundamental scientific problems. The presentation should interest professionals working in the oil and gas sectors, or crustal studies and global seismology.

More details and biography.

Date City Address
30 July Brisbane  
1 August Canberra Scrivener Room, Geoscience Australia, CANBERRA
2 August Victoria Kelvin Club, 18-30 Melbourne Place, MELBOURNE
7 August Adelaide Coopers Alehouse, 316 Pulteney St ADELAIDE
8 August Sydney The University of Sydney
14 August Hobart CODES Conference Room, University of Tasmania, Sandy Bay
15 August Perth Ground Floor, 1 Ord St, WEST PERTH

SEG DISC Short Course: Accompanying technical talk

Thursday, July 12, 2018
17:30
18:00

Finding and exploiting correlations between 3D seismic, log, and engineering data using machine learning or

The future requirements of integrated E&P: Shallow learning – but deep thinking!

Kurt Marfurt's SEG DISC will tour Australia between 11 and 25 July. After each day-long course, Kurt will speak at selected branch technical nights. These talks may be attended by members and non-members alike as with any technical night.

 

Date City Address
12 July Perth Ground Floor, 1 Ord Street, West Perth
17 July Adelaide Tuesday 17th July at the Hotel Tivoli at 265 Pirie St, Adelaide
19 July Melbourne  
24 July Canberra  
26 July Brisbane  

Please check this page for updates on course locations and times in your city. Some of these talks will talk place over lunch.

The day-long course is aimed at:

  • Seismic interpreters who want to extract more information from their data.
  • Seismic processors and imagers who want to learn how their efforts impact subtle stratigraphic and fracture plays.
  • Sedimentologists, stratigraphers, and structural geologists who use large 3D seismic volumes to interpret their plays within a regional, basin-wide context.
  • Reservoir engineers whose work is based on detailed 3D reservoir models and whose data are used to calibrate indirect measures of reservoir permeability.
  • Team leaders who wish to identify advances in machine learning technology that promise improved efficiency and accuracy in the integration of large data volumes.

SEG DISC Short Course

Wednesday, July 11, 2018
09:00
18:00

Kurt Marfurt's SEG DISC will tour Australia between 11 and 25 July using the schedule

Date City Address
11 July Perth Tech Park Function Centre, 2 Brodie Hall Drive, Bentley
16 July Adelaide Hotel Richmond, 128 Rundle Mall, Adelaide, SA 5000
18 July Melbourne The Kelvin Club, 14-30 Melbourne Place , Melbourne 3000
23 July Canberra The Scrivener Room at Geoscience Australia, corner of Jerrabomberra Ave and Hindmarsh Drive, Symonston ACT 2609
25 July Brisbane Christie Corporate Centre, 320 Adelaide Street, Brisbane 4000

Please check this page for updates on course locations in your city.

The course is aimed at:

  • Seismic interpreters who want to extract more information from their data.
  • Seismic processors and imagers who want to learn how their efforts impact subtle stratigraphic and fracture plays.
  • Sedimentologists, stratigraphers, and structural geologists who use large 3D seismic volumes to interpret their plays within a regional, basin-wide context.
  • Reservoir engineers whose work is based on detailed 3D reservoir models and whose data are used to calibrate indirect measures of reservoir permeability.
  • Team leaders who wish to identify advances in machine learning technology that promise improved efficiency and accuracy in the integration of large data volumes.

More course details and registration here.

National Rock Garden

Sunday, March 25, 2018
14:00
14:30

Friends of the National Rock Garden are invited to attend the opening of the Mt Gibraltar microsyenite display at the National Rock Garden, Barrenjoey Place, Canberra, ACT.

The Mount Gibraltar Microsyenite is an alkaline igneous intrusive body which was emplaced into Triassic Hawkesbury Sandstone around 178 Ma. It is now exposed by erosion as an imposing mountain adjacent to the rural town of Bowral. It provides a rare example of a rock that contains siderite (FeCO 3 ) as a component of a magmatic mineral assemblage.

More information

Gold Medal Award

Friday, September 22, 2017
12:00
14:00

ASEG Members are invited to join the ASEG ACT Branch to celebrate Richard Lane’s 2017 ASEG Gold Medal Award.

The ASEG Gold Medal is awarded from time to time for exceptional and highly distinguished contributions to the science and practice of geophysics by a Member, resulting in wide recognition within the geoscientific community. The ASEG President and Federal Executive are pleased to announce that the ASEG Gold Medal will be awarded in 2017 to Richard Lane.

Specifically, this award recognises Richard’s significant and distinguished contributions to the profession of geophysics in Australia and overseas through his widely recognised practical research and contributions to the understanding and application of geophysical methods in both mining and petroleum, for his frequent contributions at conferences both in Australia and overseas, and through his outstanding professional work in applied geophysics for over 30 years.

 

12 noon till 2pm

Friday September 22nd 2017

Sir Harold Raggatt Theatre

Geoscience Australia

 

Please RSVP to Marina Costelloe President Elect

Marina.Costelloe@ga.gov.au before the 18th September 2017

 

If for some reason you are unable to present on the day, could you please nominate a second for us to keep in the loop.

 

Thank you

 

Marina Costelloe

Senior Geophysicist – Geoscience Australia

President Elect ASEG.

March for Science

Saturday, April 22, 2017
12:00
14:00

The March for Science is a global event bringing together people from all walks of life who say we need more evidence and reason in our political process. We champion the public discovery, distribution, and understanding of scientific knowledge as crucial to the freedom, success, health, and safety of life on this planet.

We are a nonpartisan group, marching to promote stable public science funding, open communication of science, evidence-based policy, and greater scientific literacy and education in critical thinking.

All people who value the role of science in society are encouraged to take part in the March for Science.

More details, including specifics for your capital city, at the March for Science.

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