DRILLING ENGINEERING CHAPTER 8 Directional Drilling and Deviation

DRILLING ENGINEERING CHAPTER # 8 Directional Drilling and Deviation Control

7. 2 Build and Hold Trajectory Circumference = 2 pr S=rq q in radians max. inclination angle 1 radian = 180 o/p = 57. 29578 o 1 o = p/180 radians q = degrees per unit length = q/L = inclination angle build up rate • q = 1 o/100 ft • • • r = S /q • r = radius of curvature

S=gq (8. 1)

• q=W-T (8. 2) • To find angle T look at triangle OBA (8. 3 a) (8. 3 b) To find angle W consider triangle OBC (8. 4)

CO = g 1 (8. 5) q=W-T

(8. 6) Length of the arc section DC (buildup section) (8. 7)

Length of CB (Trajectory Path) Straight at constant inclination angle can be determined from BCO Total measured depth DM for TVD of D 3 is (8. 8)

Horizontal departure at end of build up (8. 9) True Vertical depth at end of build up section (8. 12)

Geometry for the build section

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)

New measured depth for any part of the build up (8. 13) New measured depth at TVD of (D*< D 3)(D 2<D*< D 3) (8. 16) Horizontal Departure X* (X 2<X*< X 3) (8. 18)

For r 1 < X 3 (8. 20)

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

Directional quadrants and compass measurements