Sensor to Bit Calculations. LWD 1

1. LWD 1

Sensor to Bit Calculations
March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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2. Calculating and Using Sensor to Bit Distance

March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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3. Sensor Measure Point

• Used to calculate sensor to bit
distance
• Surveys referenced to where
measurements made, not to bit
• Gamma referenced to where
measurements made, not to bit
March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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4. Identify Sensor and Probe Type

• Directional Only
– DEP, DEP2, PCD
• Gamma
– PCG
March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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5. Sensor Measure Point – DEP2

March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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6. Sensor Measure Point - PCD

March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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7. Sensor Measure Point - PCG

March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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8. Bottom Ring to Probe Bottom Distance

• Measure the distance from the
Bottom Ring Assembly to the
bottom of the probe.
(6.3’)
March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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9. Obtain BHA Tally

Bit
Motor
Stabilizer
NMDC
HOS
X-over sub
NMCD
March 7, 2001
8 ½”
6 ¾”
6 ¾”
6 ¾”
6 ¾”
6 ¾”
6 ¾”
0.75’
24.35’
5.72’
29.87’
6.21’
2.37’
28.53’
© 2001, Halliburton Energy Services, Inc.
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10. Obtain Bore Depth from Spacer Stack Calculations

54.25”
54.25”
March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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11. Calculations

•Add lengths from bit to top of
MWD mounting sub or collar
66.9’
•Subtract HOS Bore Depth
62.38’
•Subtract distance from bottom
ring to bottom of probe
56.08’
•Add sensor measure point (PCD)
56.94’
March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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12. Enter Distance in Tool Parameters

56.94
March 7, 2001
© 2001, Halliburton Energy Services, Inc.
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