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eTools Home :Oil and Gas Well Drilling and Servicing eTool Credits
 
Job Safety Analysis (JSA)
Drilling >> Drilling Ahead

Drilling ahead means the actual drilling of the well.

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.

Fig. 1. Drilling rig
Fig. 1. Drilling rig
Back to TopHandling 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.


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.
Fig. 2. Loading tubulars
Fig. 2. Loading tubulars


Fig. 3. Catwalk and V-door
Fig. 3. Catwalk and V-door

Potential Hazards:
  • Getting struck by falling tubulars due to lifting equipment failure.
Possible Solutions:
  • Instruct workers in 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), and

    • Chains and hooks.
  • Stand clear of suspended, hoisted or moving loads and be aware of your surroundings.
Additional Information:
  • RP 54. American Petroleum Institute (API), (2007, March). Includes procedures for promotion and maintenance of safe working conditions for employees engaged in rotary drilling operations and well servicing operations, including special services. Applies to rotary drilling rigs, well servicing rigs, and special services as they relate to operations on locations.

  • Accident Prevention Guide. International Association of Drilling Contractors (IADC).

  • Drilling Technology Series. Petroleum Extension Service (PETEX), University of Texas at Austin.
     
    • Unit I: The Rig and Its Maintenance

    • Unit II: Normal Drilling Operations

    • Unit III: Non-routine Operations

    • Unit IV: Man Management and Rig Management



Back to Top Preparing Drilling Fluid
Fig. 4. Drilling fluid - mud
Fig. 4. Drilling fluid - mud


Fig. 5. Mud mixing hopper
Fig. 5. Mud mixing hopper


Fig. 6. Caustic soda mixing container
Fig. 6. Caustic soda mixing container

Drilling fluid is an important component in the drilling process [more]. A 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.

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 Material Safety Data Sheets (MSDS). [Example MSDS], [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.

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

 


Back to TopStarting Drilling
Fig. 7. Lowering drill bit
Fig. 7. Lowering drill bit

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.
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.
Potential Hazards:
  • Receiving strains and sprains during lifting or controlling movement of drill collars, bit breaker, pipe, and tongs.
Possible Solutions:
  • 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.
Potential Hazards:
  • Slips, trips, and falls.
Possible Solutions: Potential Hazards:
  • Encountering shallow gas
Possible Solutions: Additional Information:
  • Well CAP. International Association of Drilling Contractors (IADC), (2006). Ensures that well control training schools adhere to a core curriculum developed by industry.



Back to TopPreparing to Break Out Pipe
Figure 8. Setting slips
Fig. 8. Setting slips

The driller stops the drill string from rotating, and hoists the drill string with the drawworks until the kelly is out of the rotary table. The driller then shuts down the mud pump(s). The floor hands set the slips around the joint of pipe. The tongs are then latched onto the tool joints above and below the connection.


Potential Hazards:
  • Pinching fingers or other body parts between slips or slip handles and rotary table.

  • Experiencing muscle strain from improper lifting technique.

  • Pinching fingers when latching the tongs onto the pipe.
Possible Solutions:
  • Implement effective, safe work procedures for using slips and tongs, which include:
    • Proper finger and hand placement on slip handles and tong handles

    • Proper stance and slip lifting techniques

    • Proper tong latching techniques
Additional Information:
  • RP 54. American Petroleum Institute (API), (2007, March).

  • Well CAP. International Association of Drilling Contractors (IADC), (2006). Ensures that well control training schools adhere to a core curriculum developed by industry.

  • Drilling Technology Series. Petroleum Extension Service (PETEX), University of Texas at Austin.



Back to TopBreaking Out Pipe

The tongs and cathead are used to break out the pipe. Either the rotary table or kelly spinner is used to spin the drill string or kelly to unscrew it from the drill pipe joint.

Fig. 9. Breaking out kelly
Fig. 9. Breaking out drill pipe


Diagram 1. Tong Swing Radius: Illustrated on the drilling floor, is a circular area marking the tong swing radius or four feet from the hole center, adjacent to the mousehole. In red, from the hole center and above in the upper quarter of the circle, is an arc marked as the hazardous area. All other areas are marked in yellow for caution. Only tong operators stand in the tong swing area, all other personnel are outside. No one should stand in the red zone.
Diagram 1: Drilling rig floor
Hazardous area layout
Tong swing radius
Potential Hazards:
  • Being struck by:
    • Swinging tongs if the tong dies fail, or the tong counterweight lines were to break

    • The slip handles if the rotary table is used to spin the drill string

    • Reverse backlash of tongs (backbiting) during spinning out operations

    • The tongs if a snub line breaks or the tongs come unlatched

    • Pipe
Possible Solutions:
  • Inspect tong dies, counterweight cables, and snub lines tourly and prior to each trip.
  • Implement an effective spinning out pipe procedure:
    • Personnel other than tong operators stand outside the tong swing radius when breaking pipe.

    • No one should stand in the red zone (see Diagram 1)

    • 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 special operational procedures when using a high torque connection.
  • Maintain good communication between floor crew and driller.
Potential Hazards:
  • Release of excess drilling mud resulting in skin contact, loss of footing, etc.
Possible Solutions:
  • Use a mud bucket to direct mud down into the rotary table.

  • Close the mud saver valve on the kelly (if present).
Additional Information:
  • RP 54. American Petroleum Institute (API), (2007, March).

  • Accident Prevention Guide. International Association of Drilling Contractors (IADC).

  • Drilling Technology Series. Petroleum Extension Service (PETEX), University of Texas at Austin.



Back to TopMaking Up Pipe in Mousehole
Fig. 10. Making up mousehole joint
Fig. 10. Making up mousehole joint


Fig. 11. Pipe in mousehole
Fig. 11. Pipe in mousehole


The crew swings the kelly out over the mousehole and stabs it into a new joint of pipe. The driller then spins up the kelly using the kelly spinner or spinning chain and the crew uses tongs to torque the joint.


Potential Hazards:
  • Being struck or pinched by the kelly.

  • Losing footing while swinging the kelly out over the mousehole and stabbing it into a new joint of pipe.

  • Being struck by or caught in the spinning chain.
Possible Solutions:
  • Use proper hand placement

  • Keep the work area around the rotating table clean and clear of mud, ice, snow, debris and other materials that may cause slipping or tripping.

  • Inspect chain for broken or distorted links. Chains with the metal reduced by wear at any point less than 90 percent of its original cross section area should be discarded.

  • Lubricate and maintain guide rollers to prevent undue wear on the chain or cable.
Additional Information:
  • Accident Prevention Guide. International Association of Drilling Contractors (IADC).

  • Drilling Technology Series. Petroleum Extension Service (PETEX), University of Texas at Austin.



Back to TopRaising the Kelly and New Joint
Fig. 12. Raising the block and kelly: The crown block is marked at the top of the rig, the traveling block above the mast and the kelly.
Fig. 12. Raising the
traveling block and kelly


The driller uses the drawworks to raise the kelly and attached joint out of the mousehole.


Potential Hazards:
  • Being struck by debris or overhead objects if the traveling block runs into the crown block or if the traveling block or swivel hits the derrick.

  • Being struck by kelly or pipe.
Possible Solutions:
  • Install a crown safety device on the drawworks and ensure proper functioning.

  • Keep personnel clear of the potential swing path of the kelly and pipe.



Back to TopAdding Pipe to the String
Fig. 13. Applying pipe dope to a connection
Fig. 13. Applying pipe dope to a connection



Fig. 14. Pulling slips
Fig. 14. Pulling slips


The new joint is guided over to the drill hole, the tool joint is doped, and stabbed into the end of the pipe suspended in the rotary table with the slips.

The joints are threaded together using the pipe spinner, kelly spinner, or spinning chain. Final torque is provided by the tongs.

The drawworks lifts the kelly and attached string to facilitate removal of the slips.


Potential Hazards:
  • Being struck by:
     
    • Swinging kelly and pipe

    • Tongs if the stabber misses the stump

    • The jerk or spinning chain
  • Being caught between the swinging pipe and the tongs.

  • Being caught between the joint of pipe being stabbed and the stump.

  • Getting pinched between tongs or pipe spinner and pipe.

  • Slips, trips, and falls.
Possible Solutions:
  • Never step over a jerk chain and stay clear of spinning chain when a connection is being made.

  • Keep hands away from end of stump or inside of pipe.

  • Keep feet and legs away from underneath tongs when the pipe is being stabbed.

  • Use proper tong latching techniques and hand and finger placement on tong handles.

  • Never stand or walk under suspended loads.

  • Keep the work area around the rotary table clean and clear of drilling fluids, mud, ice, snow, debris, and other materials that may cause slipping or tripping.

  • Inspect chains for worn or damaged links, and replace a chain having a broken or distorted link with the metal reduced by wear at any point less than 90 percent of its original cross section area.

  • See Slips, Trips, and Falls.



Back to TopResuming Drilling

Fig. 15. Lowering kelly bushing
Fig. 15. Lowering kelly bushing

The driller starts the pump and picks up off the slips. The drill crew then removes the slips. The driller lowers the string until the kelly drive bushing engages the master bushing. Once the bushings are in place, the driller begins rotating the drill string, lowers the bit back to bottom, and continues making hole.


Potential Hazards:
  • Being thrown off the rotary table when engaged.

  • Getting caught by loose clothing.
Possible Solutions:
  • Stand clear of the rotary table.



Back to TopCoring
Fig. 16. Drill core
Fig. 16. Drill core


In some cases the operator orders a core sample of the formation for testing. A special core barrel is lowered to the bottom on the drill string and is rotated to cut a core from the formation. This core is brought to the surface and examined in a laboratory.


Potential Hazards:
  • Being pinched or struck by the core barrel and associated tools during floor operations.

  • Being struck by the core as it is removed from the barrel.

  • Encountering other hazards similar to those encountered during tripping out/in.
Possible Solutions:
  • Wear appropriate PPE.

  • Instruct workers in handling and using the special tools required during drill core extraction.


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