FISH – Boris Gurevich (Curtin U.)

Title: Continuous downhole fibre-optic seismic observations during a CO2 injection
into a deep aquifer

Abstract: Geological carbon storage (GCS) requires frequent monitoring to ensure
timely detection of unwanted CO2 migration. 4D seismic can track a CO2 plume in
space and time, but cost, logistics and environmental footprint limit the
frequency of monitor surveys. This challenge can be addressed by continuous
active seismic monitoring with permanent sources and receivers. This approach
was explored at the Otway International Test Centre in the Australian state of
Victoria, where injection of 15 kt of CO2 into a sandstone aquifer 1500 m deep
was monitored by continuously acquired vertical seismic profiling with downhole
fibre-optic distributed acoustic sensors (DAS) cables as receivers and
permanently mounted vibrators as sources.

Inaddition to the active seismic monitoring, the downhole DAS system acquired two
years of passive data (starting 7 months before 3-months injection). Analysis
of these data reveals local (injection-induced), regional and global
seismicity.  The observed data show a direct signature of fluid-pressure
changes as well as temporal variations of amplitudes and travel times (of
signals from active and passive sources) caused by changes of CO2 saturation.

Bio: Boris Gurevich has MSc in Geophysics from Moscow State University (1976) and
PhD from Institute of Geosystems, Moscow, Russia (1988). After several research
appointments in Germany, UK and Israel, in 2001, he joined Curtin University
where he currently serves as John Curtin Distinguished Professor and Director
of the Centre for Exploration Geophysics. He has over 100 journal publications
in the areas of physics of rocks, poroelasticity and geophysical monitoring.

About this series: MIT Earth Resources Laboratory’s Friday Informal Seminar features guest speakers from industry and academia on topics relevant to our lab, including geophysics, seismology, rock physics, imaging, inversion, machine learning, and the energy industry. Titles and abstracts will be posted here when available. Contact fish_seminar_organizers@mit.edu for more information and Zoom password.