HYDROGEN SULFIDE

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HYDROGEN SULFIDE

• In the Oilfield

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OVERVIEW

• General H2S Information
• API Guidance
• BLM Onshore Order 6
• Other Regulations
• DOT
• EPA

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WHAT IS H2S

• Colorless gas
• Flammable
• Heavier than air
• Extremely toxic
• Rotten egg smell
• Deadens sense of smell

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WHY DOES H2S OCCUR

• Biological breakdown of organic matter in an
  anaerobic environment

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HEALTH EFFECTS

• Low concentrations (lt10ppm) irritation of eyes,
  nose, throat and respiratory system
• Moderate concentrations (10ltxgt30ppm) headache,
  dizziness, nausea, coughing, vomiting and
  difficulty breathing
• High concentrations (gt30ppm) shock, convulsions,
  coma, death

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EXPOSURE LIMITS

• ACGIH TLV (8hr) 10 ppm
• OSHA ceiling (15 min) 20 ppm
• OSHA peak (instantaneous) 50 ppm
• IDLH 100 ppm
• ATSDR MRL 0.07 ppm (acute), 0.03 ppm
  (intermediate)

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OTHER PHYSICAL PROPERTIES

• Explosive
• Reacts with water to form Sulfuric Acid
• Tears
• Lungs
• Reacts with iron/steel to form Iron Sulfide
  (extremely flammable)
• Iron sponge
• Burns to form Sulfur Dioxide (toxic gas)
• May lead to metal fatigue

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H2S PRODUCTION
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AMERICAN PETROLEUM INSTITUTE

• Recommended Practice 49 -Recommended Practice for
  Drilling and Well Servicing operations Involving
  Hydrogen Sulfide
• Applies to well drilling, completion, servicing,
  workover, downhole maintenance and plug
  abandonment procedures.
• Establishes location classifications
• Addresses personnel training, monitoring
  equipment, personal protective equipment,
  contingency planning and emergency procedures.
• Also establishes Sulfur Dioxide requirements

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LOCATION CLASSIFICATIONS

• No Hazard Area
• Condition 1 Area low hazard
• lt10 ppm
• Condition 2 Area medium hazard
• gt10ppm, lt30 ppm
• Condition 3 Area high hazard
• gt30 ppm

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WARNING SYSTEMS

• Condition 1 Area warning sign with green flag
  or light
• Condition 2 Area - warning sign with yellow flag
  or light visual and audio alarms
• Condition 3 Area warning sign with red flag or
  light visual and audio alarms

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MONITORING

• Equipment
• Manufacturer certified for H2S and SO2
• Accurate in a range from well below to well above
  action levels (H2S 10 ppm, SO2 2 ppm)
• Mixture of fixed and portable monitors as needed
  to protect workers

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MONITORING EQUIPMENT

• Used during all activities where a potential of
  H2S and SO2 to exceed action levels exists.
• Located in the following areas
• Bell nipple
• Mud return line or shale shaker
• Pipe-trip tank
• Drillers station
• Living quarters
• Other areas of potential accumulation
• Calibrated and functionally tested per
  manufacturer

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WARNING SYSTEM ACTIVATION

• Typical 2 level alarm
• 10 ppm
• 20 to 300 ppm

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TRAINING

• All personnel working in an area with potential
  of H2S and SO2 to exceed action levels exists.
• Minimum topics
• Hazards, characteristics and exposure symptoms
• Sources
• Detection equipment, warning signs and wind
  direction awareness
• Workplace procedures, location of safety
  equipment and location of safe breathing areas
• PPE
• Emergency response

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CONTINGENCY PLAN

• May be required by certain federal, state or
  local agencies.
• Must contain
• Facility specific description and maps
• Monitoring equipment locations
• Safety equipment locations
• Safe breathing area locations
• Evacuation routes
• Training and drill requirements
• Emergency response procedures

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BUREAU OF LAND MANAGEMENT

• Onshore Oil and Gas Order No. 6, Hydrogen Sulfide
  Operations

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APPLICABILITY

• All onshore Federal and Indian oil and gas
  leases.
• Drilling, completing, testing, reworking,
  producing, injecting, gathering, storing, or
  treating operations.
• Involving zones which are known or could
  reasonably be expected to contain H2S present in
  concentrations equal to or greater than 100 ppm.

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REQUIREMENTS

• Written H2S Drilling Operations Plan submitted
  with APD
• Written Public Protection Plan submitted with
  APD, notification of production or when radius of
  exposure criteria are met
• Training Program available for review upon
  request
• All plans and programs available at site

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REQUIREMENTS

• H2S Drilling Operations Plan
• Site diagrams showing all safety equipment,
  topography, exit roads, briefing (safe breathing)
  areas, flare lines and pits
• Appropriate well control equipment, personal
  protective equipment, H2S monitoring equipment,
  visual and audio warning system, appropriate mud
  system, appropriate metallurgical plan and means
  of communication from wellsite

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REQUIREMENTS

• Public Protection Plan
• Drilling or production site where
• The 100 ppm radius of exposure is greater than 50
  feet and includes any occupied residence, scholl,
  church, park, school bus stop, place of business
  or other are where the public could be reasonably
  expected to frequent

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REQUIREMENTS

• Public Protection Plan
• Drilling or production site where
• The 500 ppm radius of exposure is greater than 50
  feet and includes any part of a federal, state,
  county or municipal road maintained for public
  use

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REQUIREMENTS

• Public Protection Plan
• Drilling or production site where
• The 100 ppm radius of exposure is equal to or
  greater than 3,000 feet and includes any facility
  or part of a federal, state, county or municipal
  road maintained for public use.

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RADIUS OF EXPOSURE

• Pasquill-Gifford derrived equation
• X 1.589)(H2S concentration)(Q)0.6258
• X radius of exposure
• H2S concentration decimal equivalent of the
  volume fraction of H2S in the gas stream
• Q maximum volume of gas determined to be
  available for escape in cubic feet per day

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ESCAPE RATE (Q)

• Gas production facility maximum daily absolute
  open flow gas production rate
• Oil production facility (gas/oil ratio of
  production) (maximum daily production rate)
• Exploration well use the above from producing
  wells from the target interval in the area

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PUBLIC PROTECTION PLAN

• Must include
• responsibilities of key personnel and
  institutions for alerting the public and
  requesting assistance
• list of telephone numbers and names of response
  agencies or contractors, residents, those
  responsible for occupants of public buildings and
  those responsible for safety of public roadways
• a plat of the 100 ppm and 500 ppm radius of
  exposure showing all private and public buildings
  and roads
• emergency response measures

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PUBLIC PROTECTION PLAN

• May be required to include public education
  seminars, mass alert systems (including
  telephone, commercial radio or television), and
  public input allowances

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OTHER REGULATIONS

• OSHA
• Process Safety Management
• DOT
• Pipeline Safety Requirements
• EPA
• Risk Management Plan requirements
• SARA Title 3 requirements
• STATE SPECIFIC