Global's Ambient Seismic team successfully completed several monitoring projects over the summer, demonstrating their flexibility and expertise. They rapidly mobilized for their first project within four days instead of the normal four to six weeks. They also helped inform a client's completion plans by applying a new stress inversion algorithm to ambient seismic data collected before fracturing. The team dealt with challenges like equipment access issues due to flooding and tall corn but completed all projects safely and without incidents.

1. Summer Monitoring
Projects Demonstrate
Flexibility & Expertise
of Ambient Group
Global’s Ambient Seismic team successfully
completed another busy summer of monitoring
projects. Perseverance and unique solutions to
challenges on each project showcased the group’s
expertise and client-centered philosophy.
Rapid Mobilization
Jump-Starts Summer
Summer operations went from zero to 60 in record
time as the group’s first project materialized rapidly
due to a last minute decision by the client to do the
project.
“Their plan was always to complete the wells, but at
the last minute they decided they wanted them moni-
tored,” said Operations Manager Holli Sims.
Crew 461 and the rest of the Ambient Seismic team
jumped at the opportunity, accepted the challenge
and fully mobilized in a matter of days.
“Normally we have four to six weeks to prepare, in
this case we had four days,” said Sims.
Mobilization began in earnest May 26 and the crew
left for Williston, North Dakota May 30. Adding to the
challenge of a quick mobilization was the fact that
this was the first time the group acquired Ambient
Seismic data on a buried array that it did not install.
In this case, special adapters were needed to make
the installed grid work with Global’s equipment. Ross
Kennedy, worldwide quality & recording resource man-
ager, played a major role in making the project happen.
He was able to lean upon a long-standing vendor rela-
tionship to have the necessary adapters manufactured
and sent from China within the required time frame.
Trevor Lowe, vibrator supervisor and Wes Everett, se-
nior AutoSeis®
support technician were also key play-
ers in the fast mobilization. Lowe filled in as general
mechanic preparing trucks and trailers for the project,
while Everett prepped the recording equipment.
Once on site, insufficient documentation of the
array forced the crew to start from scratch in many
respects. One such case was that the original survey
data on the installment was inaccurate. As a solution
the crew employed auto locate capabilities, combin-
ing the GPS sampling of the AutoSeis®
system with the
free LIDAR elevation data available in many areas to
locate each receiver position at a greatly reduced cost
to that of topographic surveying.
Despite the challenges, the crew successfully mon-
itored the completion of three wells for 24 hours a day
for 26 days, completing the project with zero HSEQ in-
cidents. The crew demobilized and left North Dakota
on July 8, having delivered the final data to the pro-
cessing team led by Ambient Seismic Analyst Amanda
Klaus.
“There are two parts of this project - five stages
of reprocessing and then the three new wells,” said
Klaus. “The reprocessing was quite complicated but
ultimately resulted in a quality finished product and
an improvement to our own workflow.”
The final reprocessing was delivered to the client
August 28, at which time the processing for the three
new wells began.
SDC10334.JPG
SDC10346.JPG

2. In addition to the normal frac monitoring, this
project also involved monitoring flow-back; the pro-
cess of pumping out of the ground all the liquid that
is pumped into the ground during a frac, a first for
Global. An unusual factor that had to be taken into
consideration on each project this summer was the
occurrence of a leap second, which is a one-second
adjustment that is occasionally applied to civil time to
keep the time of day as close as possible to the mean
solar time. This interruption of time impacts GPS sys-
tems, and therefore causes a recording disruption in
the AutoSeis®
system. The Ambient Seismic team de-
vised a different plan for dealing with the leap second
on each of its projects this summer.
On this program the client decided to let AutoSeis®
run as normal and automatically reset after the leap
second interruption, accepting a slight loss in data
during the time it would take the system to reset.
Ambient Seismic Informs
Completion Plans
Completed for a long-standing client who from
the beginning has pushed the Company’s technolo-
gy to new realms, the second project of the summer
demonstrated how Ambient Seismic can inform and
impact completion plans.
Phase one of the project began in May when Glob-
al’s crew deployed an Ambient Seismic array to moni-
tor a single well. The crew collected three days of Am-
bient Seismic data before the well was completed. At
the end of three days Crew 461 retrieved the equip-
ment and sent the data to processing for a fast track
reservoir scale TFI
sm
.
In June, Global’s crew returned to redeploy the
same array and monitor the well’s completion.
“At first, the frac didn’t go the way they wanted.
They were not breaking rock,” said Sims. “The pro-
cessing group had an idea to apply a new stress in-
version algorithm. The client used the results of the
stress inversion algorithm to adjust their completion
plans and the rest of the frac went the way they want-
ed. We could do that because they had the Ambient
Seismic data prior to the frac.”
Of course, no seismic project is without its trials
and so despite the immense success of the Ambi-
ent Seismic monitoring, the crew at times struggled
against Mother Nature to maintain access to the re-
cording units.
“The first problem was that the corn planted in the
area grew to around eight feet tall when we were mon-
itoring the well. There was no way to find the HDRs
without a Garmin to lead you to it,” said Party Man-
ager Ricky Leger. “Problem two was that with all the
rain in the area the nearby river flooded. The river kept
coming up every day. Some stations were in 10 feet of
water by the time the river finally crested. When we
finished with the frac we had to get a boat to retrieve
some stations.”
Furthermore, the crew and client had to once more
decide on a course of action for dealing with the leap
second. With the leap second scheduled to occur
during the completion of the well, the crew and client
agreed that operations would take a short break be-
tween frac’ing stages to let the leap second pass and
make sure all HDR’s were back up and running before
the next well-stage was completed.
The crew wrapped things up during the first week
of July and passed the data along to processing. The
final data was delivered to the client at the end of Au-
gust, ahead of schedule.
Ongoing Monitoring of CO2
Sequestration
The final project of the summer for the group was
the continuation of an ongoing CO2 sequestration
monitoring project in Virginia. Funded by the Depart-
ment of Energy, the project is experimental in nature
with Global’s technology contributing to the under-
standing of injection wells. The Company installed
the buried array in November 2014 and has returned
for monitoring on numerous occasions. Party Manager
Mark Mercer provided leadership to the project, which
involved 16 days of monitoring.
“The job went very well, the crew did a great job
maintaining the equipment in the field and had great
support from the Houston office,” said Mercer. “The
best part was there were no recordable incidents in
very rough terrain.”
The third project of the summer also offered the
third solution to the leap second. In this case, the
crew programmed the HDR units to sleep through
the leap second. Then the day after, all HDR’s were
switched out to start a fresh cycle of 24 hour re-
cording.
The end of the project marked the end of another
busy summer for the Ambient Seismic group, which
continues to demonstrate its expertise and innova-
tion through clever, custom solutions to client prob-
lems and general project challenges, all without a
single recordable HSEQ incident.
DSC04194.JPG
DSC04195-edit.jpg