Properly
trained personnel are essential for well control
activities. Well control consists of two basic components: an active component consisting of drilling fluid pressure monitoring activities, and a passive component consisting of the
Blowout Preventers (BOPs). [More... BOPs]
The first line of defense in well control is to have sufficient drilling fluid pressure in the well hole. During drilling, underground fluids such as gas, water, or oil under pressure (the formation pressure) opposes the drilling fluid pressure (mud pressure). If the formation pressure is greater than the mud pressure, there is the possibility of a blowout.
The activities involved in well control are:
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Fig. 1. Blowout preventer stack (BOP)
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 Blowout
Prevention Program |
Potential Hazard:
- Receiving injuries
caused by loss of well
control.
Possible
Solutions:
- Appropriate training for tasks
performed. Example topics include
the following:
- Causes of kicks, including
detection
- Pressure concepts and
calculations
- Well control procedures
- Gas characteristics and
behavior
- Fluids
- Constant bottom hole
pressure well control
methods
- Well control equipment
- Regulatory information
-
Use of appropriate well
control equipment
including:
- Specification
- Installation
- Maintenance
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.
-
Standards. American Petroleum Institute (API).
-
RP 53,
Blowout Prevention Equipment Systems for Drilling Operations. Second
Edition, (2006, May).
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| Monitoring
and Maintaining
Mud System |
 |
Fig. 2. Schematic of the
circulating system:
The drill bit, drill collar, annulus, drill pipe, kelly and swivel are depicted in the upper right. Drilling mud flows
through the mud return
line (center) upon its
return to the surface
from the hole to the
shale shaker (upper
left), then to the
adjacent desander,
desilter and degasser
back to the mud tank
(upper left). Mud passes through
the suction line, and the
mud pump (center)
circulates the mud
through the discharge
line (above), the stand
pipe (upper right)
through the rotary hose
(right) and the swivel
(lower right), back to the kelly
and into the drill pipe.
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The mud circulatory
system consists of the elements
shown in Fig.2.
Each part of this system must function and be in good repair to maintain well control.
[For
more information, see
Maintenance Activities]
If the mud level increases,
it may be a sign that a kick
is in progress.
On some rigs there is a mud float level gage which
sounds an automatic alarm if
the mud exceeds a pre-specified level.
Potential Hazard:
- Loss of well
control (blowout)
Possible Solutions:
- Keep the mud
circulating system in
good working order
- Check and maintain the properties of the drilling fluid, including
proper pit level
periodically
- Properly train crew in monitoring
and well control procedures.
- Maintain a properly
functioning surface control
system.
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Fig. 3. Kick illustration:
Schematic of mud circulating
system, with a close up view of
the drill bit hitting the lower
vein at unexpected higher
pressure. KICK occurring. Mud
pit fills. Shut-in well. Above
the animation is the
illustration of the mud return
from the surface to the mud pit
through the circulating system.
View larger image
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| Installing
BOPs, Accumulator, and Choke Manifold |
Fig. 4. A blowout preventer (BOP)
with one
annular BOP on top and two ram type BOPs
are stacked together with a kill line
valve and a choke line valve.
Fig. 5. Choke manifold
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The blowout preventer
(BOP),
accumulator and
choke manifold are installed by the rig crew after the
surface casing is set and cemented. The accumulator and choke manifold have been set into place during rigging up and now need to be hooked up and tested.
The choke line valve is used to
redirect the mud from the well
bore to the
choke manifold during a
kick. The kill line valve is
used to direct drilling fluid to
the BOP during a kick.
Potential
Hazards:
- Being crushed by falling equipment if hoisting
slings fail.
- Being struck by,
pinched by or caught between equipment during installation.
Possible Solutions:
- Ensure workers stand clear of equipment being hoisted
and tag lines are used
where appropriate.
- Coordinate hoisting tasks with rig crew.
- Inspect the hoisting
slings for wear before any hoisting operation.
- Ensure all personnel wear proper PPE.
Additional Resources:
-
Standards. American Petroleum Institute (API).
-
RP 53,
Blowout Prevention Equipment Systems for Drilling Operations. Second
Edition, (2006, May). Provides information that
can serve as a guide for installation and testing of blowout
prevention equipment systems on land and marine drilling rigs
(barge, platform, bottom-supported, and floating). This
is the recommended specification for the installation, use,
and maintenance of this
equipment.
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| Testing
BOPs, Accumulators, and Choke Manifold |
Fig. 6. Choke manifold
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The BOPs, accumulators, and choke manifold should
be tested and properly maintained.
Potential Hazards:
- Being hit by hoses or sprayed by hydraulic fluid if there is a
seal or hydraulic
line failure during pressure testing.
Possible Solutions:
- Ensure workers stand clear of pressurized lines during testing procedures.
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| Maintaining
Surface Control System |
Fig. 7. BOP
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Properly
maintain the surface control system.
Potential Hazards:
- Protruding pipes and objects
- Being struck by dropped objects.
- Slips, trips, and falls.
- Atmospheric hazards
Possible Solutions:
- Wear appropriate personal protective equipment (such as hard hats, work gloves, safety shoes, and eye protection).
- Implement injury
awareness training (such as dropped objects,
working from
heights)
- Use appropriate
fall protection.
- Ensure workers are aware of the slipping and falling hazards.
- Monitor for
potential hazards (H2S, methane, O2
deficiency).
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