Why Is Bow Centralizer Considered A Profitable Deal?

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Why Is Bow Centralizer Considered A Profitable
Deal?
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A centralizer is a mechanical device that keeps
well casing from touching the sides of the
wellbore.
This gives the drilling team a complete
360-degree space around the casing for applying
cement or other completion materials.
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In the drilling industry today, there are two
kinds of centralizers used. One is bow-spring
centralizer and the other, rigid blade design.
The bow centralizer is a simple device, slightly
larger than the borehole.  It has spring
mechanism which holds the pipe in place by
applying pressure against the sides of the
wellbore.
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These are very helpful for running casing inside
previous casing or openhole sections with
extremely close annular clearances.
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Advantages Of Using Bow-Spring Design

• Bows expand to provide excellent casing
  centralization in openhole or underreamed
  sections.

• Bows recess completely into the tool body to
  allow passage through close tolerance sections
  and to protect the bows from damage.

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• These centralizers are available in float-collar,
  float-shoe and guide-shoe configurations to
  reduce the number of premium threads required in
  the casing string.

• They provide reliability and durability during
  operations.

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• Due to the flexibility of bows, they can pass
  through narrow hole sections.

• The shape and stiffness of the bows determine the
  restoring force, defined as the resistance force
  when a bow is compressed by 1/3 of its
  uncompressed height.

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Since the bow springs are slightly larger than
the wellbore, they can provide complete
centralization in vertical or slightly deviated
wells. 
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The downside to the bow-spring design is that it
does not support the weight of pipe very well. 
When the casing is heavy and/or the wellbore is
highly deviated, they may not support the casing
very well.
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The effectiveness of this type of centralizer is
heavily dependent on the restoring force.
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