H2S is one of the deadliest and most dangerous gas that have claimed lot of lives in oilfield. If you are related to oilfield industry you would have heard about H2S definitely.
In any event H2S awareness can be the difference between life and death. H2S had killed and will continue to kill oilfield workers who are not properly trained and not properly prepared to perform their duties in this potentially lethal environment.
In oilfield the simplest most routine task can be deadly sometimes, so each and every task you perform should always go for a hazard check and control measures should be placed before starting the work.
Learning about H2S awareness would make a huge difference while working in oilfield.
I would be happy in answering the following about H2S
What is Hydrogen Sulphide ?
How H2S is formed ?
Where you can find H2S?
The dangers that H2S can causes
How to control the risks associated with H2S
Oilfield H2S Safety Training
Manual
How
to stay safe while working with deadliest, highly toxic Hydrogen Sulphide gas?
Advancements in technology has helped oil and gas industry
in exploring deeper and unconventional reservoirs, to meet the increase in
demand for petroleum products, operators are required to drill in sour gas
areas where Hydrogen Sulphide (H2S) is present at high concentrations.
Hydrogen Sulphide is a life-threatening, corrosive,
flammable, highly-toxic gas. The exploration and operations of such fields has
to be undertaken at high precautions. H2S can claim lives at very low
concentrations, and also it can cause severe instantaneous failure of
high-strength steels and other metals while exposed, which would increase costs
of already high cost ventures.
H2S exposure deaths, incidents are still happening, the
highly toxic gas can takes lives in seconds if it is not detected immediately.
Analysis shows the following are the main reasons for incidents in sour gas
fields:
1.
Lack of knowledge that a H2S release could occur
and potential consequences of H2S exposure.
2.
Due to the lack of awareness relating to the occurrence
of H2S, there was in many cases, a lack of adequate preparedness to deal with
the release of toxic gas.
3.
The lack of appropriate personal protective
equipment (PPE) and suitable alarms led in a number of cases, to fatal H2S
exposure.
4.
The lack of training regarding what is H2S,
consequences of H2S exposure, procedures to work in sour environment, and using
of personal protective equipment in case of emergency.
So there is a huge need to spread awareness about H2S and in
this book you will be learning a lot about it.
The following topics about H2S will be discussed in this
book:
1.
What is Hydrogen Sulphide (H2S)?
2.
What are the Health Hazards associated with H2S?
3.
Monitoring and planning in case of emergency
4.
Emergency rescue
5.
SCBA training
Following this level of H2S awareness training, you will not
be asked to intentionally work in areas where H2S may rise.
If a job is likely to be affected by H2S, further physical
training will be required in the use of breathing apparatus, other protective
equipment and site specific contingency plans.
Chapter-2 what is
Hydrogen Sulphide?
Hydrogen Sulphide/sulphite/H2S is a colourless highly
flammable and highly toxic gas that is found as unwanted bi-product in many
industries.
H2S is considered as poison, even in low concentrations, it
can affect several different systems in body at once; respiratory system and
nervous system are mostly affected.
H2S occurs naturally in
Petroleum
Sulphur and
natural gas deposits,
Oilfield-drilling
and production,
Petrochemical
and refining plants
Manufacturing
plants,
Laboratory
operations
Water treatment
plants
Underground
mining
Chemical plants
Stagnant water
H2S is heavier
than air, and can collect in low lying areas such as
Oil/gas well
cellar deck areas
Open Drains
Oil/gas well
returns lines
Sewers
Deep
excavations
Approximately
90% of H2S sources are natural, H2S results from bacterial decay of animal and
plant material in wet areas such as marshes and swamps.
H2S is formed
in earth crust and escapes out in volcanic eruptions.
10% of H2S is
caused due to human activities and this 10% is likely get exposed by humans.
Hydrogen
Sulphide/sulphite/H2S also called as
Sour gas
Marsh gas
Sewer gas
Swamp gas
Rotten egg gas
Stink gas
Manure gas
Acid gas
Poison gas
Physical
Properties of H2S:
H2S is heavier
than air (1.189 SG)
H2S is soluble
in water, liquid, drilling mud and only releases when the mixture is agitated
H2S is gas at
ambient conditions
It is
colourless
H2S is an
invisible gas that smells like rotten eggs; however individuals should not rely
solely on their smell to detect gas. The reason why you should rely on smell is
other chemicals may mask the smell of H2S gas and also you lose sense of smell
as H2S concentration increases.
High
concentration of H2S can instantaneously lead to ability to smell.
H2S
concentrations greater than 100 ppm paralyzes the sense of smell.
Continued
exposure to low levels and high concentrations of H2S can cause people to lose
their ability to smell the gas even if it is present.
H2S is easily
dispersed by wind.
H2S is highly
flammable; it will burn or explode at 500 deg F and above.
Explosive range
from 4.3% LEL – 46% UEL (LEL- Lower explosive limit- is the lowest
concentration of fuel in air which will burn, UEL- Upper explosive limit – is
the maximum concentration of fuel in air which will burn)
H2S burns with
a blue flame producing Sulphur Dioxide (SO2), it is purposely burned in flare
stacks to help prevent accidental explosions and it will emit dangerous, toxic
sulphur dioxide (SO2), which is twice heavier than air.
Exposure to SO2
can:
Severely
irritate eyes, nose, throat and respiratory system.
Tissue damage
if exposed long term
Freezer type
burns when contacted with liquid SO2.
H2S auto
ignition temperature is 206 deg C
Flash point at
-82.4 deg C
H2S is highly corrosive gas and will cause
instantaneous failure of well equipment; H2S combines with moisture in air to
form a corrosive acid which in high concentration can result in metal fatigue.
H2S affected
tubular, pipes are subjected to hydrogen embrittlement/ Sulphide stress
cracking and can release H2S from tubular and pipes carrying H2S.
H2S reacts very
violently with
·
Strong oxidizers, metal oxides, peroxides.
·
Strong alkalis and active metals.
·
Some plastics and rubbers.
