Workbook
TYPE 1 - BUILD and HOLD
Figure 5-15: Type 1 (Build and Hold)
Figure 5-15: Type 1 (Build and Hold)
Features:-
Shallow kick-off point (KOP)
Build-up section (which may have more than one build up rate) Tangent section
Applications:
Deep wells with large horizontal displacements
Moderately deep wells with moderate horizontal displacement, where intermediate casing is not required
I KICK-OFF POINT
I KICK-OFF POINT
TANGENT SECTION
START of DROP
DROP SECTION END of DROP
HOLD
TARGET
Features: There are several variations:
Shallow KOP - Build, hold & drop back to vertical
Build-up section - Build, hold, drop & hold (illustrated above)
Tangent section - Build, hold & continuous drop through reservoir Drop-off section
Applications: Disadvantages:
Multiple pay zones - Increased torque & drag
Reduces final angle in reservoir - Risk of keyseating
Lease or target limitations - Logging problems due to inclination
Well spacing requirements
Deep wells with small horizontal displacements
KICK-OFF POINT k BUILD-UP SECTION
TARGET
Figure 5-17: Type 3 (Deep Kickoff and Build)
Features:
Deep KOP Build-up section Short tangent section (optional)
Applications:
Appraisal wells to assess the extent of a newly Repositioning of the bottom part of the hole or Salt dome drilling
Disadvantages:
Formations are harder so the initial deflection may be more difficult to achieve
Harder to achieve desired tool face orientation with downhole motor deflection assemblies (more reactive torque)
Longer trip time for any BHA changes required discovered reservoir re-drilling
On multi-well platforms, only a few wells are given deep kick-off points, because of the small slot separation and the difficulty of keeping wells vertical in firmer formation. Most wells are given shallow kick-off points to reduce congestion below the platform and to minimize the risk of collisions.
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