Advanced method
- For vertical wells with the zenith angle of less than 3 degrees the null azimuth is filled in with the values ranging from 0 to 360 degrees with the interval of 45 degrees. In this case the wellbore will be spiral, but it will not fall outside the target area and the cone of uncertainty.
- The below table shows the details of filling in null azimuth values for deviated S-wells and low-angle horizontal wells.
|
Interval |
Zenith angle |
Depth |
Methods of filling in null azimuth values |
|
Top depth intervals |
<= 3 degrees |
|
from 0 to 360 degrees with interval of 45 degrees |
|
3-10 degrees |
Up to 100 m |
from 0 to 360 degrees with interval of 45 degrees |
|
|
|
Less than 100 m |
from 0 to 360 degrees with interval of 90 degrees |
|
|
Internal depth intervals |
|
|
Interpolation of the azimuth value from the first known azimuth value before the empty interval to the last known azimuth value after the empty interval. |
|
Bottom depth intervals |
<= 3 degrees |
|
from 0 to 360 degrees with interval of 45 degrees |
|
3-10 degrees |
|
Interpolation of values ranging from the last known azimuth value before the unspecified interval to the last point of the inclination measurement. |
|
|
>= 10 degrees |
|
The last known azimuth value before the unspecified interval is extended to the last point of the inclination measurement. |
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