WA

Seismic attenuation, dispersion, and anisotropy in porous rocks: Mechanisms and Models

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.

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. Boris is currently an SEG Honorary Lecturer.

The Australian Continent: A Geophysical Synthesis is designed to provide a summary of the character of the Australian continent through the extensive information available at the continental scale, as a contribution to the understanding of Australia's lithospheric architecture and its evolution. The results build on the extensive databases assembled at Geoscience Australia, particularly for potential fields, supplemented by the full range of seismological information, mostly from The Australian National University. To aid in cross comparison of results from different disciplines, information is presented with a common projection and scales.

Please register here.

The WA Branch of the Australian Society of Exploration Geophysicists invites you to attend the upcoming ASEG WA Branch Christmas Party and AGM.

The AGM will commence at 5pm and the 2019 WA committee will be voted in.

The Secretary of the WA branch of the ASEG will be standing down so we are looking for interested members to nominate for this role and for other committee positions to be voted on at the AGM. The nomination form is available here. Please send your nominations to either the wasecretary@aseg.org.au or wapresident@aseg.org.au. All nominations for the committee must be received by 7th December.

The Branch Christmas party will follow immedaitely after the AGM. Drink tokens and light catering will be provided but REGISTRATION and RSVP is REQUIRED (please note any dietary requirements).

Please email wasecretary@aseg.org.au with any queries or for additional information.

Please drive safe - nearby red cat route and parking at Wilson and CPP facilities.

Six undergraduate and post-graduate students from UWA and Curtin will present their recent work in the field of geophysics at our annual student night. Attendees will be asked to vote on the best presentation, and one student will be awarded a prize courtesy of the WA branch.

Annual student tech night with presentations by several Curtin and UWA students

Vincent Crombez from CSIRO and Tasman Gilfeather-Clark from UWA will present to other young professional members of the ASEG and PESA

Crombez: From cores to stratigraphic modelling: an innovative workflow to characterize unconventional targets. Application to the Montney and Doig Formations (W. Canada)

In self-sourced reservoirs, the occurrence of hydrocarbons is linked with in-situ organic content and thermal maturity, while the effective extraction of this resource depends on the brittleness of the reservoir which is mainly controlled by the mineralogy and the rock fabric. The aim of this study is to improve the understanding of sedimentary heterogeneities in shale plays, based on outcrop and well data from the Triassic Montney and Doig Formation (Fms), lab analyses and numerical modelling.

Our workflow comprises 3 stages: (1) Well correlations, based on sequence stratigraphy, providing an understanding of the 3D stratigraphic architecture of the basin. (2) Integration of Rock-Eval VI, ICP-MS/AES analysis on cores, cuttings and outcrop samples distributed along a basin-wide cross-section highlighting the controls on organic accumulation (dilution, destruction, production). (3) A process-based forward modelling of the stratigraphic evolution of the basin with DionisosFlow, providing a quantification of the controlling factors as well as 3-D distribution of reservoir heterogeneities at basin-scale.

The integration of the geochemical analysis in the stratigraphic framework showed that the organic content in the Montney and Doig Fms is controlled by different combinations of: organic production, dilution and destruction, depending on the location along the depositional profile and on the depositional sequence. The stratigraphic modelling provided the opportunity to understand this complex interaction and study the distribution of organic heterogeneities. The dynamic of dilution, destruction and production processes can thus be spatially and temporally quantified and correlated with the stratigraphic architecture and the dynamic of the basin. Lastly, stratigraphic modelling provided important feedbacks on organic matter accumulation conceptual models and geochemical proxies interpretation.

With in-situ organic content and thermal maturity, while the effective extraction of this resource depends on the brittleness of the reservoir which is mainly controlled by the mineralogy and the rock fabric.

Vincent works at CSIRO as a Post-Doctoral research fellow and he participates as a mentee in the ASEG-PESA Mentoring Program.

Gilfeather-Clark: Machine Learning for Land Classification - A SOM Case Study of Broken Hill   

Self-Organising Maps (SOM) is an unsupervised learning algorithm, used in this work to complete landmass classification analysis of the area to the North of Broken Hill. An examination of current ML landmass classification methodologies is introduced followed by a brief review of SOM. Applications of SOM for mineralisation targeting and data QC are identified in a data rich setting. The results of the study confirm the efficiency of the SOM algorithm for clustering lithological groups in land classification studies. Perhaps most notable is SOM’s ability to highlight variation in cover without needing to assign labels, which has been identified as a key aspect moving forward in Australia’s mining future, when considering the vast expanses of Australia which is composed of sub cropping rock.

Tasman completed Bsc. Geology and Geophysics in 2014 at Macquarie University. He then worked in exploration geophysics surveying with various junior exploration companies for a year doing IP, Gravity, & Magnetics Surveys around Australia. He returned to Macquarie to complete a Masters of Research under Dr Kate Selway studying the relationship between grain-size and conductivity over a shear zone near the Musgraves in central Australia. During his Masters he was co-chair of GESSS NSW conference committee and team leader of the Team Macquarie's submission to the Frank Arnott Award, where he worked with David Pratt of Tensor Research and Bruce Dixon formerly of CSIRO, on the work he's presenting tonight. He's recently moved to Perth to complete a PhD with the Center for Exploration Targeting at UWA under Prof. Eun Jung Holden of the Geo Data algorithms team.

With the proliferation of fibre-optic cables, has emerged an increased level of interest in their use as sensors. With the employment of appropriate hardware, cables can be used for  both temperature and vibration monitoring

More details.

Digital Disruption in Exploration: A Symposium on Disruptive Innovation in Resource Exploration

http://cess-dde.com/

UWA Woolnough Society Wine and Cheese night

September 14, 630-830pm

UWA Edward de Courcy Clark Science Museum, Perth

https://www.trybooking.com/book/event?eid=416773&