Primer on H2S

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4.  Used in farming – crop dusting and organic
farming applications
 Nuclear Engineering
 Epsom salts
 Laxative
 Exfoliate
 And of course.... matches
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5.  Beta lactum antibiotics
◦ Penicillins
◦ Cephalosporins
◦ Monobactums
 Dermatological treatments
◦ Psoriasis
◦ Eczema
◦ Acne
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6.  Occurs naturally in;
◦ Crude petroleum
◦ Volcanic gases
◦ Hot springs
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7. ◦ Can form from organic materials (plants, human,
animal waste decomposition in oxygen-free
environments.
 It’s called Anaerobic Decomposition and it happens in;
 Manure piles
 Sewers
 Swamps
 Composts
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8. Q: If a well has 25% H2S content and is a couple
miles away from me... What does that mean to
me?
A: Many people live near sour gas wells all their
lives with no problems at all because it
dissipates into the atmosphere and becomes a
very small amount of H2S in the atmosphere
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9.  If there is a leak, at that’s rare, the
percentage of sour gas in a well quickly
dissipates when it incorporates into the
atmosphere.
 Thus, a well that has a 25% sour gas content
may only create 1 or 2 ppm in a zone
immediately next to the well, and dissipates
further from there.
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10. Modeling determines a dispersion zone
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12.  When a well produces a percentage of H2S it
is just that, a percentage. This measurement
is not how we sample air quality to determine
if there is any danger to people.
 The air we breath is sampled and reported in
ppm – ppm stands for “parts per million” and
that’s how we measure H2S in the air... In
parts per million.
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13.  You may only be exposed to a fractional ppm if you live
near a sour well and if there is a leak
 You can sit in the hot springs all day at 2 or even 6
ppm, and the same is true for H2S in low concentrations
from a well
 If a sour gas well gets out of control, it is flared to burn
off the H2S
 In Alberta, sour gas well facilities are designed,
monitored and highly regulated for the public safety
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14.  Energy Resources Conservation Board
 AUC regulates sour gas pipelines
 Strict Engineering Standards are applied to all
sour gas well equipment
 MSDS information is on every well in Alberta.
 Crews are trained on live wells @ Nisku training
site
 Drillers and Rig Managers are trained and
certified in blowout prevention
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15.  6,000 sour gas wells in AB
 250 processing plants
 18,000 km of pipelines
 105 wells within or near Calgary
 98% of sulphur removed is converted to
elemental sulphur
2007 Data – Gov. Alberta
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16.  Best engineering practices
 Setbacks to human dwellings and areas
 Handling and transportation requirements
 Sensing equipment at sites with redundant
backup sensors
 Flaring guidelines
 Evacuation requirements (15 ppm)
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17. Lease setbacks are
areas large enough
from human or
livestock to ensure
there is enough
room for sour gas to
dissipate into the
atmosphere to a safe
level
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18.  Drill pipe used in sour gas wells must be
resistant to corrosion
 NACE International
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19.  checks for corrosion to maintain pipeline
integrity
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23.  H2S concentration of greater than four parts per
million a.k.a. >4ppm in the atmosphere
◦ .0047 ppm // half of humans sense the rotten egg smell
◦ 5 ppm - 15 ppm // alarm ranges
◦ 10 ppm - 20 ppm // borderline concentration for eye irritation
◦ 150 ppm – 250 ppm // Sense of smell disappears
◦ 320 ppm – 530 ppm // Pulmonary edema, potential death
◦ 530 ppm – 1,000 ppm // Rapid breathing to respiratory arrest
◦ 800 ppm // lethal for 50% of humans with 5 minutes exposure
◦ 1,000 ppm // immediate collapse and respiratory arrest
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25.  Alberta has the toughest H2S regulations that
exist in the World with an amazing track
record of success.
 The most famous event in Alberta was the
Lodgepole blowout of Nabors Rig 18 while
drilling under the Pembina River at a depth of
about 3,000 meters.
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26.  1982 – Amoco well blow out 12 miles from
Lodgepole (the worst part)
◦ In the atmosphere, no concentrations >10ppm were
found within a 20 Km radius
◦ Within the 20km radius, only a few residences were
found to have concentrations > 20ppm
◦ Highest concentration measured at Lodgepole was
14.5ppm
◦ Drayton Valley (45km from well) had highest reading of
4.5ppm
◦ Highest reading in Edmonton was 0.5ppm
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27.  Upper Hot Springs – 2ppm
 Miette Hot Springs – 6ppm
 Lodgepole –Drayton Valley reached 5ppm
 Lodgepole –Edmonton reached .5
 In Cynthia and Drayton Valley it was less than
1 ppm about 95 and 96 percent of the time
and about .1 for Edmonton
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28. Mastrb1aster
Video 1
Video 2
Video 3
Video 4
Video 5
Landcruiser45
Conventional Blow Out
dlelemental
Nabors 18
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29.  During the 26 day period the well was not on
fire...
◦ Edmonton – odour detected but concentrations
were less than 0.1ppm 93% of the time
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30.  Produced natural gas containing H2S smells
like rotten eggs
◦ A very heavy dose can be fatal
◦ It collects in low lying areas because it’s heavier
than air
◦ It also deadens the sense of smell
◦ Can burn and irritate eyes
◦ Was used by the British as a chemical agent in WW1
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31. Sweet natural gas has no smell –
so we add mercaptans which
create that funky smell as the
gas is used to heat and cook
with
It’s a safety feature and is
designed so that humans can
detect the odour if there is a leak
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32.  Special chemicals are added in order to make it easy
for humans to detect gas leaks
 Sweet gas without H2S content, is odourless, the
mercaptans are added as a safety feature
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33. The school board had plumbers tap into an oil
companies residue line.
Gas leaked into an enclosed crawlspace that
ran the entire 253 foot length of the building’s
facade.
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34. Since natural gas is odourless – nobody
had any idea there was a leak and could
not possibly predict what would happen
next.
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