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Course 902 - Well Site Preparation and Drilling Safety

Safety guides and audits to make your job as a safety professional easier

Drilling Ahead Safety

drilling rig


Drilling ahead means the actual drilling of the well. The drilling rig will drill holes up to 14,000 feet. The rig can drill 1 to 22 or more wells on one pad. Eight to 20 people may work on a typical drilling rig.

Specific drilling processes vary, but many of the work hazards are similar. The following generic tasks assume the use of a kelly and rotary table. Other rig designs may include the use of a top drive.

Handling Tubulars

  • The pipe is unloaded from trucks onto the pipe rack.
  • The floor crew brings pipe from the pipe rack and catwalk, using the catline, air hoist or hydraulic winch, up to the drilling floor and places it in the mousehole.
  • This is done for every connection.

Note: The rig supervisor should hold a pre-job meeting with the crew to review responsibilities and to coordinate the operations to be performed.

Handling Tubulars (Continued)


Potential Hazards:

  • being struck by rolling or falling tubulars
  • being struck by or caught between tubulars and other objects during movement (for example, being struck by tubulars being tailed into the rig floor)
  • slips, trips, and falls

Possible Solutions:

  • Use powered industrial truck (forklift) properly.
  • Work the tubulars from the ends from ground level.
  • Chock or pin tubulars on the racks properly.
  • Level your pipe racks properly.
  • Stand clear of suspended, hoisted, or moving loads.
  • Be aware of tubulars or equipment being lifted through the V-door.
  • Instruct workers about the need for proper use, inspection, and maintenance practices.
  • Before each tour inspect the:
    • wire rope and slings
    • catline ropes and knots (do not allow a rope to lie in standing water)
    • chains and hooks
  • Stand clear of suspended, hoisted or moving loads and be aware of your surroundings.

Preparing Drilling Fluid

mud tanks

Drilling fluid is an important component in the drilling process. There are several types of drilling fluids used depending on the drilling conditions encountered:

  • Water-based muds are used most frequently. The base may be either salt or fresh water.
  • Oil-based muds
  • Synthetic materials- The oil and gas extraction industry has developed many new oleaginous (oil-like) base materials from which to formulate high-performance drilling fluids.
  • Air and form fluids may be used in drilling wells. These fluids are less dense than drilling muds.

Drilling fluid is required in the wellbore to:

  • cool and lubricate the drill bit,
  • remove the rock fragments, or drill cuttings, from the drilling area and transport them to the surface,
  • counterbalance formation pressure to prevent formation fluids (i.e. oil, gas, and water) from entering the well prematurely (which can lead to a blowout), and
  • prevent the open (uncased) wellbore from caving in.

The mud is monitored throughout the drilling process. A mud engineer and/or the Derrickman may periodically check the mud by measuring its viscosity, density, and other properties.

Preparing Drilling Fluid (Continued)

mud pumps

Potential Hazards:

  • burns, or physical injury caused by contact with skin or eyes
  • being exposed to explosions or violent reactions from chemicals mixed improperly
  • being exposed to inhalation hazards
  • receiving strains and sprains
  • slips, trips and falls

Possible Solutions:

  • Ensure workers follow the safe handling procedures found in Safety Data Sheets (SDS). [29 CFR 1910.1200]
  • Wear appropriate personal protective equipment, including, eye and face protection. [29 CFR 1910.132], [29 CFR 1910.133]
  • Wear appropriate respiratory protection when handling chemicals and/or mud additives. [29 CFR 1910.134]
  • Provide an eyewash station and other appropriate flushing apparatus as recommended by the MSDS. [29 CFR 1910.151(c)]
  • Provide adequate ventilation.
  • Use proper mixing procedures.
  • Use designated containers for mixing certain chemicals (for example, baffled container with lid).
  • Substitute less hazardous materials or use pre-mixed mud.

Note: Tank cleaning is a high-hazard operation requiring confined space entry procedures, training for personnel, PPE, and specialized equipment. [29 CFR 1910.146]

Starting the Drilling Process


To start drilling, a surface drill bit is attached to a bottomhole drill collar, which is in turn attached to the kelly. Once made up, the driller lowers the bit through the rotary table and engages the mud pump(s) and checks for leaks and other abnormalities.

The driller lowers the drill string and the kelly bushing is set in the rotary drive bushing and the rotary is engaged.

The driller then slowly lowers the bit to bottom and begins the drilling operation.

Potential Hazards:

  • being struck by the tongs, the make-up chain, or pipe
  • being caught between collars and tongs, spinning chain, and pipe
  • receiving strains and sprains during lifting or controlling movement of drill collars, bit breakers, pipes, and tongs
  • slips, trips, and falls
  • encountering shallow gas

Possible Solutions:

  • Implement an effective pipe handling, make-up, break-out procedure:
    • Stand outside the tong swing radius when breaking pipe.
    • Use proper tong latching techniques and use proper hand and finger placement on tong handles.
    • Stand clear of the rotary table when it is rotating.
  • Use a tail rope on the spinning chain to keep hands away.
  • Use proper lifting technique.
  • Hoist slowly to limit pipe momentum.
  • Use mechanical lifting aids such as a rig floor winch.
  • Use tail rope to guide as necessary.
  • Comply with the Blowout Prevention Program



Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. Potential hazards associated with handling tubulars include all of the following, except _____.

2. Solutions to the potential hazards associated with handling tubulars include all of the following, except _____.

3. Drilling fluid is used in the wellbore to do each of the following, except _____.

4. Hazards associated with drilling fluid processes include all of the following, except _____.

5. Solutions to the hazards associated with starting the drilling process include all of the following, except _____.

Have a great day!

Important! You will receive an "error" message unless all questions are answered.