198
which is still a GHG, but a less powerful one. The combustion products of flared
VOCs are oxidized compounds that are less prone to reacting with sunlight and
creating ground-level ozone.
Of course, the ideal goal is to not release anything into the air at all. It is critically
important that upstream producers, midstream transmission companies, and downstream distributors find and repair natural gas leaks. Since methane absorbs infrared
frequencies of light as a GHG, infrared detectors can be used to identify stray gas
and fugitive emissions (Soeder 2019). Many of these instruments use a laser tuned
to the absorption wavelength of methane and determine the concentration by the
attenuation of the beam. It is possible to deploy these instruments in drones, or
make static measurements by shining a laser beam along the top of a long stretch of
pipeline.
A system that is gas-tight will not only reduce GHG emissions, but will also
prevent fires and explosions. Production-transmission-distribution losses from the
national natural gas system may equal 1.5–2% of the total throughput (McKenna
2011). This estimate is in line with other estimates for gas leakage from the EPA and
the Gas Research Institute although industry generally believes the losses are lower.
These fugitive emissions have nothing to do with shale gas or fracking specifically,
but are an issue with the entire natural gas distribution system nationwide.
One of the worst culprits for fugitive emissions is the old gas distribution infrastructure under our cities. Many of the original iron gas pipes laid down in places
like San Francisco and Boston are more than a century old, and they leak (McKenna
2011). Along with water, sewer, and power lines, natural gas systems are an infrastructure problem in the United States suffering from age and years of neglect. The
cost of digging up streets and the low price of gas have limited the enthusiasm of
utility companies for repairing leaks, except in emergencies. Development of a
method for sealing leaks in old gas lines without digging them up would be
very useful.
The final requirement for improving air quality and reducing GHG emissions is
to locate and properly P&A old legacy gas wells, which have been shown to emit
significant amounts of methane (Kang et al. 2014, 2016). Again, this has nothing to
do directly with shale gas and fracking, but these old wells add to the GHG burden
already in the atmosphere. Many legacy wells were divested by mainstream operators when production fell off or the well watered-out. Small operators obtained
these at very low prices and operated them as marginal producers or “stripper wells”
that would only produce a few barrels of oil or small volumes of gas per day. The
larger operators had unloaded a liability for proper P&A of the well. The small
operator (sometimes consisting of only one person) would collect petroleum from
the wells for a while, but eventually the site would be abandoned. These individuals
typically did not have the resources to properly P&A the wells, and they would
often just cut off the casing at the surface and leave an unsealed hole.
Several states, notably Pennsylvania and Wyoming have active campaigns to find
old wells and properly plug them. Challenges include dealing with thousands of
poorly documented wells (Pennsylvania alone is estimated to have over 100,000),
missing records concerning well location and depth, casing cut flush with the
10 Mitigation and Remediation
which is still a GHG, but a less powerful one. The combustion products of flared
VOCs are oxidized compounds that are less prone to reacting with sunlight and
creating ground-level ozone.
Of course, the ideal goal is to not release anything into the air at all. It is critically
important that upstream producers, midstream transmission companies, and downstream distributors find and repair natural gas leaks. Since methane absorbs infrared
frequencies of light as a GHG, infrared detectors can be used to identify stray gas
and fugitive emissions (Soeder 2019). Many of these instruments use a laser tuned
to the absorption wavelength of methane and determine the concentration by the
attenuation of the beam. It is possible to deploy these instruments in drones, or
make static measurements by shining a laser beam along the top of a long stretch of
pipeline.
A system that is gas-tight will not only reduce GHG emissions, but will also
prevent fires and explosions. Production-transmission-distribution losses from the
national natural gas system may equal 1.5–2% of the total throughput (McKenna
2011). This estimate is in line with other estimates for gas leakage from the EPA and
the Gas Research Institute although industry generally believes the losses are lower.
These fugitive emissions have nothing to do with shale gas or fracking specifically,
but are an issue with the entire natural gas distribution system nationwide.
One of the worst culprits for fugitive emissions is the old gas distribution infrastructure under our cities. Many of the original iron gas pipes laid down in places
like San Francisco and Boston are more than a century old, and they leak (McKenna
2011). Along with water, sewer, and power lines, natural gas systems are an infrastructure problem in the United States suffering from age and years of neglect. The
cost of digging up streets and the low price of gas have limited the enthusiasm of
utility companies for repairing leaks, except in emergencies. Development of a
method for sealing leaks in old gas lines without digging them up would be
very useful.
The final requirement for improving air quality and reducing GHG emissions is
to locate and properly P&A old legacy gas wells, which have been shown to emit
significant amounts of methane (Kang et al. 2014, 2016). Again, this has nothing to
do directly with shale gas and fracking, but these old wells add to the GHG burden
already in the atmosphere. Many legacy wells were divested by mainstream operators when production fell off or the well watered-out. Small operators obtained
these at very low prices and operated them as marginal producers or “stripper wells”
that would only produce a few barrels of oil or small volumes of gas per day. The
larger operators had unloaded a liability for proper P&A of the well. The small
operator (sometimes consisting of only one person) would collect petroleum from
the wells for a while, but eventually the site would be abandoned. These individuals
typically did not have the resources to properly P&A the wells, and they would
often just cut off the casing at the surface and leave an unsealed hole.
Several states, notably Pennsylvania and Wyoming have active campaigns to find
old wells and properly plug them. Challenges include dealing with thousands of
poorly documented wells (Pennsylvania alone is estimated to have over 100,000),
missing records concerning well location and depth, casing cut flush with the
10 Mitigation and Remediation