Micro dogleg occurs in areas where there are several corrections in inclination and azimuth and it most likely happens in hard/soft interbedded rock. If there are micro dogleg areas in the well, the bottom hole assembly can get stuck.
Micro Dogleg Causes Stuck Pipe
Warning signs when you get stuck due to Micro Dogleg
- Hard and soft streak formations are drilled. You can easily observe from the changes in ROP.
- Inclination and azimuth are frequently changed.
- Drilling the well with a mud motor causes this issue because of rotating and sliding operations.
Stuck identification for Micro Dogleg
- Drilling torque and drag are erratic.
- It can happen while tripping or drilling.
- Circulation can be established without any restriction.
What should you do for this situation?
- If the drill string is stuck while moving up, jar down with maximum trip load. Torque can be applied with caution while jarring down.
- If the drill string is stuck while moving down, jar up with maximum trip load without applying any torque in drill string.
- If the drill string is free, you may need to consider back reaming to clear micro dogleg.
Preventive actions:
- Minimize changes in inclination and azimuth
- Back ream operation should be performed when hard/soft streak is drilled.
- Slow down tripping sleep when entering possible problematic zones.
References
John Mitchell Drilbert Engineering, 2002. Trouble-Free Drilling Volume 1: Stuck Pipe Prevention. Edition. Drilbert Engineering Inc.
Fanarco.net. 1999. Stuck Pipe Prevention Self-Learning Course. [ONLINE] Available at: http://www.fanarco.net/books/drilling/stuck-pipe.pdf. [Accessed 21 June 2016
Steve Devereux, 2012. Drilling Technology in Nontechnical Language, 2d Ed.. 2 Edition. PennWell Corp.
