Air, Gas and Mist Drilling

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PETE 689 Underbalanced Drilling (UBD)
Lesson 5 Air, Gas and Mist Drilling Read UDM
Chapter 2.1-2.4, Pages 2.1-2.74
Harold Vance Department of Petroleum Engineering
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Volume Requirements
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Volume Requirements

• Identify the geometry of the borehole section(s)
  to be drilled with each of the techniques
• Determine the geometry of the associated
  drillstring sections to be drilled with each of
  the techniques
• Estimate the anticipated drilling ROP in each
  section basded on the type of rock formation to
  be drilled

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Volume Requirements

• Determine the elevation of the drilling site
  above sea level, the temperature of the air
  during the drilling operation, and the
  approximate geothermal temperature gradieng
• Decide whether direct or reverse circulation
  techniques will be used
• Calculate the minimum volume requirements to
  drill each section. (e.g. liquid flow rate, gas
  injection rate)

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Volume Requirements

• Using the minimum volumetric flow rates, estimate
  the bottom-hole pressure, surface injection
  pressures, and compressor power
• Predict the pressure underbalance at the pay zone
  f the objective of using UBD is to minimize
  formation damage
• Peform borehole stability analysis

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Volume Requirements

• Select a contractor whose compressors will
  provide the drilling operation with the
  appropriate pressures and flow rates
• Estimate the approximate volume of fuel required
  by the compressors to drill the well.

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Example Problems
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Example 2.1
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Example 2.1
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Example 2.1
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Example 2.1
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Example 2.1
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Example 2.1
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Example 2.2
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Example 2.2
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Example 2.2
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Example 2.2
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Example 2.2
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Example 2.2
t is in Deg F
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Example 2.3
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Example 2.3
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Example 2.3
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Example 2.3
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Example 2.4
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Example 2.4
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Example 2.4
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Example 2.4
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Example 2.4
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Example 2.7 Vertical/Deviated/Slant Holes
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Example 2.7
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Example 2.7
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Example 2.7
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Example 2.7
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Example 2.7
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Example 2.7
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Example 2.7
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Example 2.7
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Example 2.8 Reverse Circulation
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Example 2.8
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Example 2.8
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Example 2.8
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Example 2.8
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Example 2.9 Gas Volume Correlations
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Table 2.2
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Example 2.9
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Example 2.10 Deviated Hole
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Table 2.3
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Example 2.10
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Example 2.10