|Development Geology Reference Manual|
|Series||Methods in Exploration|
Disregard for safety at the wellsite can be the cause of injury or death. The wellsite is a hostile environment, often either very cold or very hot, wet, and slippery. Hazards include heavy equipment being moved around from all directions, heights, and industrial activities such as welding, the presence of flammable fluids, poisonous gases, machinery, vehicles, and noise.
Planning for safety
Working efficiently and effectively in this environment calls for being aware of the surroundings and planning accordingly. Before entering the drilling site, ask yourself the following questions:
- How is the site laid out?
- What are the current and potential hazards?
- What protective equipment is needed?
- What are the warning signals and emergency procedures at this site?
- What are the escape routes?
- What training and survival courses are needed and available?
Government safety regulations
Safety at a wellsite is governed by federal and state regulations, as well as by the operator's in-house codes. Federal regulations are established in the Safety and Health Standards set forth by the Occupational Safety and Health Administration (OSHA, 1983). In many states, these regulations are administered by state agencies. State regulatory agencies can also have their own specific standards that are more stringent than OSHA requirements. A prudent operator should be aware of all levels of safety regulations.
Rig safety equipment
A drilling site is equipped with various safety features, including
- First aid kits
- Fire extinguishers
- Emergency air supplies
- Warning sirens
- Gas monitors
- Wind indicators
The location of this equipment should be noted prior to an emergency since emergency conditions can be noisy and can be made more dangerous by limited visibility and confusion.
The offshore environment poses special safety issues. Transportation to and from the rig and location of the rig are issues that require special training in helicopter and boat safety and in procedures on how to get on and off the rig. When arriving at an offshore location, a safety briefing is given that includes the rules and alarms followed on the rig as well as the escape boat assignments. Each rig should have a weekly safety drill. This practice may include having personnel donning life jackets, air packs, or survival suits and assembling at the escape boat. Some drills include boarding the escape capsule and starting the engine.
Personal safety equipment
Personal safety equipment is usually determined by the employer and must be in compliance with state and federal regulations. Required equipment includes the following:
- Hard hat
- Safety shoes
- Safety glasses
- Hearing protection
The following are recommended:
- Well-fitted, protective clothing
- CPR and first aid training
Do not have the following:
- Long shoe strings
- Floppy gloves
- Neckties or fringes
- Long, loose hair
- A bad attitude
In general, the minimal personal safety equipment includes a hard hat, steel-toed boots, and eye and ear protection. In some cases, it may also include gas monitors and supplied air respirators.
Hard hats provide some protection from small falling objects—but only if worn. Plastic hard hats are generally used because they provide protection from electrical shock. Metal hard hats are used only in situations where heat or chemical reactions can deteriorate the plastic. A wool liner can be attached inside the crown of the hat for cold weather work.
Steel-toed boots can provide a high degree of protection from dropped or rolling objects. Steel-toed boots are available in a variety of materials and styles. Generally a good leather boot with a nonskid sole is preferred. Boots can be made of waterproof materials and can be insulated if needed. There are even steeltoed “tennis shoes” available.
Eye protection is either in the form of goggles or safety glasses. Safety glasses can be provided as prescription glasses and can be mounted in respirator face pieces if necessary. Slip-on side panels are available for side protection of the eyes and should be worn at all times when on any rig.
Ear protection is recommended in areas where noise levels exceed 85 decibels. Two types of ear protection are available:
- Protective muffs mounted on a hard hat
- Small plugs made of soft plastic that are inserted into the ear canal
Either style should be rated to reduce the noise level below 85 decibels.
Two types of wellsite gas monitors are used:
- Fixed monitors are installed at the wellsite in locations where gas might be expected to break out or accumulate (e.g., bell nipple, shale shaker, mud mixer, and rig floor).
- Portable personal monitors are worn at any location where fixed monitors are not available and a toxic gas hazard exists. Personal monitors continuously monitor gas concentrations and provide a sound and light warning.
Air respirators require specific training before they can be used in life-threatening environments. There are two general types of air respirators designed for personal use:
- The 5-minute air tank with a face mask is designed to provide emergency escape from the site
- The more familiar self-contained breathing apparatus (SCBA or air pack) is designed for short-term work in hazardous environments (Figure 1).
In using either system, a good face mask fit is essential. Because facial hair tends to break the seal, beards are often not permitted on the wellsite. On drilling rigs where known hazards from poisonous gas exist, air lines are installed and workers plug their individual air hoses into the manifold system.
Hazards from flammable gases and fluids
Flammable gases and fluids are a prime concern on a drilling site, and smoking is not advised anywhere except in open or designated areas. Carbon dioxide, nitrogen, hydrogen sulfide, or any other gas can be a killer in a confined space if it displaces oxygen. Typical confined spaces at a wellsite include the rig cellar, mud tanks, and mud pits.
A special concern at many drilling locations is hydrogen sulfide. Hydrogen sulfide (H2S) is a colorless gas that has a “rotten egg” odor at concentrations below 1 ppm (part per million). At 10 to 20 ppm, protective steps against long-term exposure need to be taken to prevent worker discomfort, such as eye irritation. At concentrations above 20 ppm, the gas deadens the sense of smell and headaches or nausea may develop. At 600 ppm (or less for some people), the sense of smell is immediately paralyzed, breathing stops, and without immediate resuscitation, death follows.
When entering a site with known or suspected H2S present, conditions should be determined immediately from site personnel or warning signs. When a well is drilling with a risk of H2S release, it is important to be continually aware of the wind direction, site layout, safety equipment, and the various means of escape.
Hydrogen sulfide is a heavier than air and will flow along the ground surface and collect in low spots. Clothes can also absorb H2S dissolved in water or oil. As the material dries or warms (as in a heated vehicle, room, or dryer), the gas can be released, creating a dangerous situation.
Other common hazards
Additional common hazards can come from a number of sources:
- Slipping on water, ice, drilling muds, or lubricants
- Falling from rig ladders
- Tripping over the numerous pieces of equipment lying around the rig
The old sailor's adage of “one hand for the ship and one for yourself” is good advice at any wellsite.
- ↑ 1.0 1.1 Michigan Department of Labor, 1989, Personal protective equipment, Part 33: Safety Standards Division Occupational Safety Standards for General Industry, Lansing, MI.
- ↑ American National Standards Institute, 1972, Acceptable concentrations of hydrogen sulfide: ANSI Report No. Z37., 2, New York.
- ↑ American Petroleum Institute, 1974, API recommended practices for safe drilling of wells containing hydrogen sulfide: API Report No. 49, Dallas, TX, 11 p.