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  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 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

H 2 S PRODUCTION

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 H 2 S and SO 2 Accurate in a range from well below to well above action levels (H 2 S = 10 ppm, SO 2 = 2 ppm) Mixture of fixed and portable monitors as needed to protect workers

MONITORING EQUIPMENT  Used during all activities where a potential of H 2 S and SO 2 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 H 2 S and SO 2 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 Onshore Oil and Gas Order No. 6, Hydrogen Sulfide Operations

APPLICABILITY All onshore Federal and Indian oil and gas leases. All onshore Federal and Indian oil and gas leases. Drilling, completing, testing, reworking, producing, injecting, gathering, storing, or treating operations. Drilling, completing, testing, reworking, producing, injecting, gathering, storing, or treating operations. Involving zones which are known or could reasonably be expected to contain H 2 S present in concentrations equal to or greater than 100 ppm. Involving zones which are known or could reasonably be expected to contain H 2 S present in concentrations equal to or greater than 100 ppm.

REQUIREMENTS Written H 2 S Drilling Operations Plan submitted with APD Written H 2 S Drilling Operations Plan submitted with APD Written Public Protection Plan submitted with APD, notification of production or when radius of exposure criteria are met 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 Training Program available for review upon request All plans and programs available at site All plans and programs available at site

REQUIREMENTS H 2 S Drilling Operations Plan H 2 S 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, H 2 S monitoring equipment, visual and audio warning system, appropriate mud system, appropriate metallurgical plan and means of communication from wellsite

REQUIREMENTS Public Protection Plan 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 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 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 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 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. 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: Pasquill-Gifford derrived equation: X = [1.589)(H 2 S concentration)(Q)] X = radius of exposure H 2 S concentration = decimal equivalent of the volume fraction of H 2 S 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 Gas production facility = maximum daily absolute open flow gas production rate Oil production facility = (gas/oil ratio of production) (maximum daily 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 Exploration well = use the above from producing wells from the target interval in the area

PUBLIC PROTECTION PLAN Must include: 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 May be required to include: public education seminars, mass alert systems (including telephone, commercial radio or television), and public input allowances

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