NOW TOURING
2022–23 DISTINGUISHEDINSTRUCTOR SHORT COURSE
WITH MARK E. WILLIS

Distributed acoustic sensing for seismic measurements –what geophysicists and engineers need to know

2 June • TOKYO
Course Duration: One day
Description
Geoscientists and engineers are very comfortable using
seismic data sets acquired with geophones, hydrophones,
and accelerometers because we have a long, well defined
set of standards for acquiring, processing, and interpretingthem. However, distributed acoustic sensing (DAS) seismic
measurements are rapidly augmenting, and in some casesreplacing, the data from these conventional tools.
Technologists are frequently unaccustomed to using DAS
seismic data sets since it directly acquires relative strain orstrain rate measurements and not the more familiar pressure,displacement, velocity, and acceleration data. There arealso acquisition parameter selections that must be madeto optimize the acquired data to accomplish the purposeof the seismic survey. This course is designed to build anintuition and understanding of the value, limitations, andapplications of DAS seismic technology. In addition to thelecture and accompanying book, software will be provided
which will allow the student to interactively explore DAS
seismic technology.

The course will cover:
What are many of the applications for DAS technology?
How do conventional and DAS seismic measurement
systems compare?
• How can we convert between DAS and geophonemeasurements?
• What are the physics behind DAS measurements and thecomposition of optical fiber? Do different types of fiber
optic cables offer advantages?
• How is a DAS acquisition system architected? How does
the fiber optic cable deployment method affect the DASmeasurements?
••

SM

Connecting the World of Applied Geophysics

What is the gauge length and how does it affect theacquired data? How does the pulse width interact withthe gauge length to improve data quality?
• What is the angular response of the fiber optic cable
to incoming seismic signals? How does the angularresponse of the fiber affect VSP, surface seismic, andmicroseismic measurements?
• What are the sources of DAS noise and how are they
mitigated? Can we remove the effects of poor fiber optic
cable coupling from the seismic data?
• How can we plan and prepare for a DAS seismic survey?
What are the key decisions that need to be made and can
we model them?
• What are the field deployment issues that we shouldaddress? How is handling fiber optic cables different
from standard electrical cables? Can the health of the
deployed fiber be determined before the survey begins?
How is the depth (or distance along the fiber) of eachchannel of seismic data determined?
•GoalsThe goal of this course is to create a basic intuition for thevalue of DAS seismic measurements as well as the acquisitionand processing decisions that affect its quality. The everpresent trade-offs will be discussed between resolution
and signal to noise ratio. The limitation of one component
measurements will be countered by the advantage ofspatially dense sampling. After taking this course, it will
be easier for the technologist to decide whether to acquire
seismic data using DAS, as well as how to choose optimum
acquisition and processing parameters.

ce@seg.org • seg.org/DISC

Who should attend

Instructor Biography

All those interested in obtaining, processing, and/or using
seismic data acquired using DAS measurements shouldattend. Managers will get an overview of DAS technology.
Geophysicists who are involved in deciding how to acquire thenext seismic survey will gain understanding in the possible
options for using DAS. Processing geophysicists will gain
insight into the advantages and artifacts of DAS seismic
data. Interpreters will gain an understanding of the potential
advantages of strain data as well as what artifacts may be in
the data. Reservoir engineers will obtain an understanding of
the way fiber optic cables are deployed and what information
they allow us to collect.

Mark E. Willis is the Chief Scientific Advisor of Borehole
Seismics at Halliburton. He is responsible for mentoring
technologists, developing and promoting geophysicalinnovations, and fostering long term client relationships.
Previous to joining Halliburton in 2011, he worked in various
research technology, supervisory and management positions
at Mobil Oil, Cambridge GeoSciences, Massachusetts
Institute of Technology Earth Resources Laboratory, andConocoPhillips.

This course does not require advanced mathematicalknowledge. The objective is to provide an intuitiveunderstanding of the physics and trade-offs made foracquiring and processing DAS seismic data. It is expected thatthe students will have some basic understanding of seismic
technology. The software workbench provided will allow
students to interactively explore simulated seismic data bychanging the acquisition and processing parameters.

What to bringIn his career he has performed research and development
in distributed acoustic sensing, VSP technology, deep soniclog imaging, fracture identification using seismic data (timelapse VSP, microseismics, and surface seismic scattering),
interferometric imaging, Kirchhoff and reverse time depth
migration, full waveform inversion, machine learning, velocity
model building, and sonic waveform processing.
Willis holds a B.S. in Applied Math and Physics from theUniversity of Wisconsin – Milwaukee and a Ph.D. in Geophysics
from MIT. He has written over 100 papers, publications, andpresentations, and holds multiple patents. He is a member of
the SEG, EAGE, SSA, SPWLA, ASA, and Sigma Xi.

Participants are strongly encouraged to bring their personal
laptops. Cloud-based access to the DAS simulation softwareand class exercises will be provided online.

SM

Connecting the World of Applied Geophysics

ce@seg.org • seg.org/DISC