American Oil and Gas Reporter - November 2023 - 67

SpecialReport: Emissions Monitoring
That is partly because experience
from mandatory LDAR surveys shows
they eventually reach a point of diminishing
returns. " In the United States,
surveys need to be done quarterly. Canada
mandates three surveys a year, though
new regulations may make them monthly, "
he describes. " For the past few
years, the number of leaks identified by
each survey has fallen as companies
have improved their repair and maintenance
programs. "
Given that progress, Tang says LDAR
surveys will likely become more frequent
in the years ahead. They also will involve
stricter scrutiny and documentation.
" Through proposed changes to Appendix
K, the Environmental Protection Agency
has outlined detailed guidelines that cover
not only how often surveys need to take
place, but also how they must be performed.
This includes the route taken, the documentation
necessary to define each leak,
and the training requirements for everyone
involved in the survey, " Tang notes.
The proposed changes stipulate that
novices perform several surveys under
the guidance of a senior operator before
they can conduct surveys independently.
To facilitate such supervision and streamline
other compliance tasks, Tang says,
ChampionX has introduced a new optical
gas imaging camera that streams data
wirelessly. " Instead of having six people
hover around an individual camera to see
what the operator is looking at, everyone
can pull out their phones or tablets to visualize
exactly what the camera is seeing, "
he describes. " This makes it much easier
for senior operators to oversee and train
new surveyors.
" On top of that, the camera includes
highly accurate global navigation satellite
system (GNSS) positioning and records
technicians' routes, what they are pointing
at and how long they pointed. And through
a unique 'Gas Enhancement Mode,' the
camera identifies, quantifies and tags the
gases it observes, " Tang continues. " These
features create a digital audit trail while
allowing users to focus on performing
the survey correctly. "
According to Tang, a well-done survey
can be extremely informative. " OGI surveys
identify all emissions, whether fugitive
or intentional, " he assures. " Each
survey only captures a moment in time,
but once a company has a solid sample
size of 8-10 surveys, it can start correlating
venting to the operational setting and
configuration of the facility. These correlations
help the company predict emissions
and potentially reduce them. "
To illustrate the possibilities for optimization,
Tang points to a midstream
facility with several compressors. " By combining
emissions and operational data, we
gather operational insights for optimal facility
configurations, such as whether it is
better to operate every compressor at 70%
capacity or run a few at 90%, " he says.
" Over time, the resulting efficiency gains
can add up to lower costs and emissions. "
Continuous Monitoring
To gain an even deeper understanding
of emissions, Tang recommends continuous
monitoring systems. These systems
watch for emissions constantly and trigger
an alert when something unusual happens,
allowing emissions to move to a " survey
by exception " model. This model enables
operators to perform surveys when necessary,
usually yearly or after the continuous
monitors spot a leak.
The benefits of continuous monitoring
can go beyond detecting emissions, as
emissions can indicate other operational
problems. " For one of our clients, a monitor
picked up anomaly emissions at a remote
facility around 9 p.m. and dispatched an
alert to an on-call technician. Within 90
minutes, that technician arrived at the facility
and discovered the emissions' source. While
methane had triggered the alarm, it was
leaking from a sight glass alongside oil, "
he relates. " Had the leak continued, the
costs would have been much higher. "
In addition to allowing fast and efficient
responses, continuous monitoring can
show emission trends. Ideally, Tang says,
the monitors will confirm that emissions
are shrinking as operators make changes
to address them and guide such changes
by revealing emissions that are difficult
to capture in periodic surveys.
" One of the biggest unknowns in emissions
estimates is how often pressure
relief valves activate and how long they
stay open, " Tang illustrates. " Many of
these valves are old enough that they
may not close completely even after pressures
have returned to a safe range. With
continuous monitoring, we know when
valves stay open too long and can send
someone to investigate why. "
Whether a leaking valve is discovered
through a survey or continuous monitoring,
it can lead to long-term improvements not
just with emissions but also with reliability
and maintenance programs. " In the short
term, companies can fix a valve leak with
grease, " Tang considers. " This works, but
if the valve has to cycle frequently, the
grease will migrate and the leak will return.
No one can afford to replace every valve
that leaks, but with a sophisticated monitoring
system instead of industry emissions
estimates, they can identify the most problematic
ones and replace them. "
Where deploying continuous monitoring
Continuous emissions monitors can quantify and mitigate emissions that can be difficult
to catch with periodic leak detection and repair surveys alone. As an example, ChampionX
says the monitors can alert operators when pressure relief valves stay open even after
pressures have returned to safe levels, a common source of unexpected emissions.
NOVEMBER 2023 67
American Oil and Gas Reporter - November 2023

Table of Contents for the Digital Edition of American Oil and Gas Reporter - November 2023
