Page 257 - Well Logging and Formation Evaluation
P. 257
Solutions to Exercises 247
The Field components should look as follows:
30
25
20
15
Ftot
F (micro T) 10 Fax
Fxy
Ftot meas
Fxy meas
Fax meas
0
0
2660 2680 2700 2720 2740 2760 2780 2800 2820 2840 2860 2880
–5
–10
Depth
It is seen that for AX dir and HS dir, good agreement is seen only in the
vicinity of the pole. This is because the directions become poorly defined
once the fields become weak far from the pole.
The asymmetric behavior below 2781.5ft may be attributed to a second,
weaker pole along the target well axis. It may be seen that the addition
of a second, north pole at 2147.5ft in the target well, having a strength of
1000mWb, could improve the match.
