Casing is pipe usually larger in diameter and longer than drill pipe
and is used to line the hole. Casing operations occur
periodically throughout the drilling process starting with the surface casing, intermediate casing, and
ending with production string which takes place during well completion.
The activities involved in casing operations can vary according to the type of
casing being installed, but generally fall into these steps:
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Fig. 1. Installing conductor casing
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Installing Casing Tools |
Fig. 2. Special casing elevators
Fig. 3. Derrickman latching elevators
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Specialized casing handling tools are necessary to run casing.
Note: The special service supervisor should hold a pre-job meeting with
the special service crew and other involved personnel to review
responsibilities and to coordinate the operations to be performed.
Potential Hazards:
- Being struck by or caught between tubulars and other objects during movement (such as being struck by tubulars being tailed into the rig floor).
- Experiencing strains and sprains from maneuvering tools.
- Falling from work platform and/or stabbing board.
Possible Solutions:
- Stand clear of suspended, hoisted or moving loads. Be aware of
tubulars or
equipment being lifted through the V-door.
- Use proper hand and foot placement to avoid pinch points,
including use of tag lines.
- Use rig floor winch or other powered equipment to handle
heavy casing tools.
- Use fall protection while installing equipment in the
derrick.
- See
Slips, Trips, and Falls.
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Running Casing into the Hole |
Fig. 4. Lifting casing onto rig floor
Fig. 5. Casing stabber
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Casing is run
into the hole to a pre-determined depth.
Note: The special service supervisor should hold a pre-job meeting with
the special service crew and other involved personnel to review
responsibilities and to coordinate the operations to be performed.
Potential Hazards:
- Hazards are similar to those for
drilling
ahead or
tripping.
- Getting caught between, struck by, or pinched by the power
tongs,
casing or other equipment.
- Being struck by or caught between tubulars and other objects during movement (for example, struck by tubulars being tailed into the rig
floor).
- Falling from the stabbing board or work platform.
- Getting struck by dropped objects.
Possible Solutions:
- Include the casing crew and the drilling crew when conducting a JSA and pre-job safety meeting
to coordinate the activities
of casing operations.
- Stand clear of suspended, hoisted, or moving loads. Be aware of tubulars or equipment
being lifted through the V-door.
- Emphasize all normal worker safety procedures, such as fall
protection, PPE, placement of hands and feet, and teamwork and
communication between workers.
- Implement full fall protection program for the casing stabber.
- Identify clearance between the stabbing board and casing elevators.
- Secure all items used by the casing stabber
overhead with a safety line.
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Installing Casing Accessories |
Fig. 6. Casing guide shoe
Fig. 7. Installing casing centralizer
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As casing is being run, accessories such as centralizers, scratchers, guide shoe, and a
float collar are installed and used as needed.
Note: The special service supervisor should hold a pre-job meeting with
the special service crew and other involved personnel to review
responsibilities and to coordinate the operations to be performed.
Potential Hazards:
- Dropping guide shoe or float collar onto legs or foot.
- Getting fingers pinched between tools and casing tongs when manually moving guide shoe or float collar.
- Back strain
- Exposure to hazardous materials, especially thread lock compounds.
Possible Solutions:
- Use winch, air hoist, or other powered equipment to handle guide shoe, float collar, or other heavy casing equipment.
- Use appropriate PPE as required by the MSDS.
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Circulating and Cementing |
Fig. 8. High pressure lines
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After the casing is landed, drilling fluid is
circulated through the casing and annulus to remove any residual
gases and to condition the mud.
After circulating and conditioning the mud,
the casing is cemented. During this process the casing is reciprocated or rotated to allow
the scratchers to work to remove excess wall cake to give the cement
a better bond.
Usually another special servicing company is hired to conduct
cementing operations.
Potential Hazards:
- Being struck by high-pressure lines failing if not secured properly.
- Having a high pressure connection failure caused by mismatched or
excessively worn hammer unions.
Possible Solutions:
- Hobble high-pressure lines properly.
- Use proper equipment inspection techniques to include
hammer unions (Note: This is a particular problem with 602 and 1502, as they
will couple but will not hold beyond the lower pressure rating
number).
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Safety Alerts. International Association of Drilling
Contractors (IADC).
- High Pressure Lines And Hammer Unions. Alert 98-01, (1998, April).
- More On Mismatched Hammer Unions. Alert 99-33, (1999, November).
- Additional Serious Incidents With Mismatched Hammer Unions. Alert 00-15, (2000, May).
- Mismatched Hammer Unions Still Being Found. Alert 03-16, (2003, April).
- Mismatched Hammer Union Results in a Fatality. Alert 06-01, (2006, January).
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