2. Directional Drilling and Deviation Control
DRILLING ENGINEERING
CHAPTER # 8
Directional Drilling and Deviation Control

3. 7.2 Build and Hold Trajectory
Circumference = 2pr
S=rq
q in radians max. inclination angle
1 radian = 180 o/p = o
1o = p/180 radians
q = degrees per unit length = q/L
= inclination angle build up rate
q = 1o/100ft
r = S /q
r = radius of curvature

4. S = g q
(8.1)

5. To find angle T look at triangle OBA
(8.2)
q = W - T
To find angle T look at triangle OBA
(8.3a)
(8.3b)
To find angle W consider triangle OBC
(8.4)

6. CO = g1
(8.5)
q = W - T

7. (8.6)
Length of the arc section DC (buildup section)
(8.7)

8. Length of CB (Trajectory Path)
Straight at constant inclination angle can be determined from BCO
Total measured depth DM for TVD of D3 is
(8.8)

9. Horizontal departure at end of build up
(8.9)
True Vertical depth at end of build up section
(8.12)

10. Geometry for the build section

11. Measure depth and Horizontal departure before reaching maximum angle along any part of build up.
Consider  intermediate inclination angle 
XN=Horizontal Departure at C
DN=Vertical depth
Consider DOC
(8.10)
(8.11)

12. New measured depth for any part of the build up
(8.13)
New measured depth at TVD of (D*< D3)(D2<D*< D3)
(8.16)
Horizontal Departure X* (X2<X*< X3)
(8.18)

13. For r1 < X3
(8.20)

14. Build-hold-and-drop and hold (modified-S)

15. Directional quadrants and compass measurements