If you already know that the stuck pipe is caused by wellbore geometry, these following instructions are guide lines on how to free the stuck drill string.
What should you do to free the stuck pipe caused by wellbore geometry?
- If the drill string gets stuck while moving up, jar down with maximum trip load and torque can be applied into the drill string while jarring down. Be cautious while applying torque, do not exceed make up torque.
- On the other hand, if the drill string gets stuck while moving down, jar up with maximum trip load.DO NOT apply torque in the drill string while jarring up.
- Flow rate must be reduced while attempting to free the drill string.Do not use a high flow rate because it will make the stuck situation become worse and you will not be able to free the pipe ever.
- To free the string, a jarring operation may take a long time, so please be patient.
- If a formation that gets stuck is limestone or chalk, acid can be spotted to dissolve cuttings around the pipe.
- If the drill string is stuck in a salt formation, spotting fresh water is another choice to clear the salt in the annulus.
- Please always seriously consider the situation regarding well control prior to spotting lightweight stuff (acid or fresh water) around the drill string. You must ensure that you are still over balance formation pressure otherwise you will be dealing with well control too.
What should you do after the string becomes free?
- Increase flow rate and circulate to clean wellbore. Flow rate must be more than the cutting slip velocity in order to transport cuttings effectively.
- Reciprocate and work pipe while cleaning the hole.
- Ensure that the wellbore is clean prior to continuing the operation.
- Back ream or make a short trip to the section that caused the problem.
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.