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| What is Secondary Well Control? |
importance extends not only to the drilling crew but also to those who
are involved in the design of the well and to those who service the well.
It is of paramount importance that specific procedures be set in place
to assure that personnel are trained in oil control management so as
to avoid poor drilling practices. Equipment must also be continually
inspected and tested, monitored and maintained, to assure that it
works properly in order to avoid equipment failures. If these two
specific measures are not considered, there can be blowouts or
uncontrolled and explosive eruption of formation fluid from the well,
which potentially can result in fire.
The consequences:
• Critical damage to equipment
• Serious injury to personnel, in some cases resulting in death.
• Loss of valuable resources and consequently loss in profitability.
• Loss of future production
• Irreparable damage to the environment
• Legal action
Control Management Stages:
Well control management consists of three stages: Primary Well
Control, Secondary Well Control, and Tertiary Well Control.
Primary Well Control
In primary well control, personnel play a key factor. They must
continually monitor the well to assure there is sufficient drilling fluid
pressure (hydrostatic pressure) in the well hole to prevent the influx of
formation fluid (i.e. a kick) into the wellbore. To assure sufficient
hydrostatic pressure, two conditions must be met:
1. The hydrostatic pressure in the wellbore must be greater than
the pressure of the fluids (i.e. the mud) in the formation being drilled,
2. The hydrostatic pressure must be less than the formation
fracture pressure.
To insure this:
• Always maintain the well full with an adequate amount of fluid
having the correct density.
• Continuously monitor active pit volumes.
• Look for any changes in the density, volumes, and flow rate of
drilling fluids from the wellbore and make necessary modifications.
Secondary Well Control
Secondary oil well control is performed when primary oil well control
has failed to prevent formation fluids from entering the wellbore. This is
done by implementing the correct use of the blow-out preventers
(BOPs). The number, size and rating of the BOPs used depend on the
depth of the hole and the maximum anticipated formation pressures.
Then the following procedures can be used to control kick:
• The Driller’s method
• Wait and weight method
• Concurrent
• Volumetric,
• Lubricate and Bleed
• Bull heading methods
Tertiary Well Control
Tertiary Well Control is performed when both primary and secondary
well control steps have failed. For tertiary well control, the procedures
will depend on the operating conditions and recommendations based
on the circumstances under which secondary control was lost.
However, there are some emergency procedures which are commonly
performed:
• Pump heavy mud to control the well with equivalent circulating
density
• Pump barite or a heavy weighting agent to plug the wellbore
• Pump cement to plug the wellbore
• Form a plug with diesel-bentonite
• Drill a relief well to hit an adjacent well that is flowing and kill the
well with heavy mud
are involved in the design of the well and to those who service the well.
It is of paramount importance that specific procedures be set in place
to assure that personnel are trained in oil control management so as
to avoid poor drilling practices. Equipment must also be continually
inspected and tested, monitored and maintained, to assure that it
works properly in order to avoid equipment failures. If these two
specific measures are not considered, there can be blowouts or
uncontrolled and explosive eruption of formation fluid from the well,
which potentially can result in fire.
The consequences:
• Critical damage to equipment
• Serious injury to personnel, in some cases resulting in death.
• Loss of valuable resources and consequently loss in profitability.
• Loss of future production
• Irreparable damage to the environment
• Legal action
Control Management Stages:
Well control management consists of three stages: Primary Well
Control, Secondary Well Control, and Tertiary Well Control.
Primary Well Control
In primary well control, personnel play a key factor. They must
continually monitor the well to assure there is sufficient drilling fluid
pressure (hydrostatic pressure) in the well hole to prevent the influx of
formation fluid (i.e. a kick) into the wellbore. To assure sufficient
hydrostatic pressure, two conditions must be met:
1. The hydrostatic pressure in the wellbore must be greater than
the pressure of the fluids (i.e. the mud) in the formation being drilled,
2. The hydrostatic pressure must be less than the formation
fracture pressure.
To insure this:
• Always maintain the well full with an adequate amount of fluid
having the correct density.
• Continuously monitor active pit volumes.
• Look for any changes in the density, volumes, and flow rate of
drilling fluids from the wellbore and make necessary modifications.
Secondary Well Control
Secondary oil well control is performed when primary oil well control
has failed to prevent formation fluids from entering the wellbore. This is
done by implementing the correct use of the blow-out preventers
(BOPs). The number, size and rating of the BOPs used depend on the
depth of the hole and the maximum anticipated formation pressures.
Then the following procedures can be used to control kick:
• The Driller’s method
• Wait and weight method
• Concurrent
• Volumetric,
• Lubricate and Bleed
• Bull heading methods
Tertiary Well Control
Tertiary Well Control is performed when both primary and secondary
well control steps have failed. For tertiary well control, the procedures
will depend on the operating conditions and recommendations based
on the circumstances under which secondary control was lost.
However, there are some emergency procedures which are commonly
performed:
• Pump heavy mud to control the well with equivalent circulating
density
• Pump barite or a heavy weighting agent to plug the wellbore
• Pump cement to plug the wellbore
• Form a plug with diesel-bentonite
• Drill a relief well to hit an adjacent well that is flowing and kill the
well with heavy mud
