NSW

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.

Sponsors

Platinum sponsors
Gold sponsor

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.

Two full day workshops being held prior the AEGC 2018 Conference offer a unique insight into the structural framework and complex mechanism that dictate the petroleum and mineral systems in various sedimentary basins.

One is entitled "Practical geological interpretation of potential field data sets and the importance of basement" while the other is entitled "Structural Interpretation in Exploration Geology, Extension, Compression and Salt".

See the conference website for more details.

Registrations are open for the Young Professionals Networking Event, which is now confirmed to run during the AEGC Conference thanks to some generous corporate sponsorship.

Gold
Silver
Bronze

This event provides young geoscientists an opportunity to connect with fellow Young Professionals and industry representatives alike. 

There is no age limit, but is intended for people aged under 35, or those new to the profession (less than 10 years experience). 

Please register ASAP as numbers are limited. 

Details

• Date: Monday 19th February 2018
• Time: 6.30pm - 8.30pm
• Location: The Endeavor Tap Rooms - 39/43 Argyle St, The Rocks NSW 2000
• Drinks and Canapes provided.
• Cost: $20 pp for Young Professionals (affiliated with ASEG, PESA or AIG)

Directions

• Ferry – From ICC 11 walk to Darling Harbour (usually from wharf 26) to Circular Quay.  20 minutes on the Ferry.  6 minute walk to Endeavor Tap Rooms
• Train – From ICC 15 walk to Town Hall train station.  20 minute train to Circular Quay station.  6 minute walk to Endeavor Tap Rooms
• Bus – From ICC 13 walk to Kent Street.  5 minute bus from Kent Street to Wynyard Station.  14 minute walk from Wynyard Station to Endeavor Tap Rooms
• Taxi – 15 minutes approximately $25/$30
• Walk – 30 minutes

If you have any further enquiries please dont hesitate to contact me at ypadmin@aseg.org.au

Kind regards,

Megan Nightingale, on behalf of the ASEG YP Special Interest Group

AEGC2018 conference presentation skills workshop

Find your Voice - Present with Confidence

Nothing is more important in a presentation than what YOU have to say so; what if breaking some conventions meant your audience actually listened?

What if a willingness to try something new was the key to improving your delivery?

In this get up and do it workshop hovering somewhere between Acting Class, Stand Up and Therapy – Be prepared to justify why you think what you’re doing presently in presentation works!

Using empathy based methods, this workshop asks you to resist emulating the style of others and generate new ideas around creating impact.

As an audience, we don’t perhaps discuss the machinations of what it is to be presented to.

• What is our experience?
• Why do we recall some things and not others?
• How does it feel to be presented to – By You?

Part one of this live demonstration format includes discussion focussing on presentation creation and preparation as well opportunities for participants to deliver an ‘Elevator Pitch’ more effectively.

The second half of the session will see small groups working together on a group presentation challenge to be delivered and adjudicated.

With an emphasis on confidence and team building, this workshop offers an opportunity for collective learning and vibrant discussion while reinforcing the importance of strong professional and personal messaging.

What might it take for you to be “Perfectly Presentable”?

Register for this workshop at TAS

Date: Sunday 18th February 2018

Time: 9am-4pm

Location: Spinnaker B room at the Adina Apartment Hotel, Darling Harbour.

Lunch, morning and afternoon tea included

New pricing

• $225 (+GST) pp for members of the ASEG, AIG or PESA Young Professionals networks
• $375 (+GST) pp for ASEG, PESA and AIG members
• $475 (+GST) pp for non-members

Facilitator biography

This workshop will be facilitated by London-based Doug Knight.

London based Doug Knight is a creative, high-energy presenter, trainer and coach.

As a Public Speaking and Presentation consultant, Doug has inspired clients studying and working across a multitude of sectors including Britain’s Oil and Gas industry.

A trained actor Doug, travelled to the UK from Australia soon after graduating.  10 years in West End theatres was followed by aviation public relations notably helping launch the world’s first A380 Super Jumbo.

From popular and targeted presentation workshops for large corporations to pitch clinics for startups within London's tech. community, Doug’s approach identifies and capitalizes on an individual’s existing abilities.

A heightened awareness of presentation potential is the rewarding benefit for clients, but the rapport Doug develops with groups and individuals is his personal and most important measure of success.

Find out more about Doug by visiting his Website.

"This workshop is being organised by the Young Professionals special interest group of the ASEG as part of a wider effort to improve early career training opportunities. Geoscientists from all society affiliations and experience levels are welcome to attend.

I've been working with Doug to adapt the latter part of the workshop to geoscience presentation challenges with a focus on conference oral or poster formats and including typical geoscientific content. However, if group presentation therapy is not your thing, feel free to contact Doug directly via his website for in-house or 1-on-1 training.

I know it will be a fun day and I look forward to welcoming you to the premiere offering of this workshop in Australia." Dr Jarrod Dunne

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.

Submissions are invited for the Geoscience Educators (AUGEN) Conference which will be held between 5 and 6 August, 2017 at The University of Sydney.

The conference is aimed at first-time and experienced educators, students, postdoctoral fellows, professional society representatives, high school science teachers, plus academic, industry and government geoscientists.

The conference has six main themes

1. Strategies for supporting success in earth science education
2. Creating opportunities for work-integrated learning (WIL) in earth sciences
3. Earth science education and literacy inside and outside university walls
4. Research in the classroom and laboratory
5. Improving quantitative approaches in earth science teaching and learning
6. Tomorrow’s global geoscience workforce

Registration details are available here.

The next conference will be held in conjunction with PESA and the AIG and will be called the Australian Exploration Geoscience Conference (AEGC).

Initial abstract submission closes on 12 May, 2017.