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HYDROGEN SULFIDE. In the Oilfield. OVERVIEW. General H 2 S Information API Guidance BLM Onshore Order #6 Other Regulations DOT EPA. WHAT IS H 2 S. Colorless gas Flammable Heavier than air Extremely toxic “Rotten egg” smell Deadens sense of smell. WHY DOES H 2 S OCCUR.
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HYDROGEN SULFIDE In the Oilfield
OVERVIEW • General H2S Information • API Guidance • BLM Onshore Order #6 • Other Regulations • DOT • EPA
WHAT IS H2S • Colorless gas • Flammable • Heavier than air • Extremely toxic • “Rotten egg” smell • Deadens sense of smell
WHY DOES H2S OCCUR • Biological breakdown of organic matter in an anaerobic environment
HEALTH EFFECTS • Low concentrations (<10ppm)– irritation of eyes, nose, throat and respiratory system • Moderate concentrations (10<x>30ppm)– headache, dizziness, nausea, coughing, vomiting and difficulty breathing • High concentrations (>30ppm)– shock, convulsions, coma, death
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)
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
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
LOCATION CLASSIFICATIONS • No Hazard Area • Condition 1 Area – low hazard • <10 ppm • Condition 2 Area – medium hazard • >10ppm, <30 ppm • Condition 3 Area – high hazard • >30 ppm
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
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
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 • Driller’s station • Living quarters • Other areas of potential accumulation • Calibrated and functionally tested per manufacturer
WARNING SYSTEM ACTIVATION • Typical 2 level alarm • 10 ppm • 20 to 300 ppm
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
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
BUREAU OF LAND MANAGEMENT • Onshore Oil and Gas Order No. 6, Hydrogen Sulfide Operations
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.
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
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
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
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
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.
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
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
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
PUBLIC PROTECTION PLAN • May be required to include: public education seminars, mass alert systems (including telephone, commercial radio or television), and public input allowances
OTHER REGULATIONS • OSHA • Process Safety Management • DOT • Pipeline Safety Requirements • EPA • Risk Management Plan requirements • SARA Title 3 requirements • STATE SPECIFIC