How To Free Stuck Pipe (Oilfield)

This article is a summary of how to free stuck pipe caused by three main mechanisms which are wellbore geometry, differential sticking and packing/bridging off. It will give you some ideas which you can apply for your operation.

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Free Stuck Pipe Caused By Wellbore Geometry

These following instructions are guide lines on how to free the stuck drill string caused by wellbore geometry.

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 drill string while jarring down. Be caution 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 high flow rate because it will make the stuck situation became worse and you will not be able to free the pipe forever.

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How To Free Stuck Pipe Caused By Wellbore Geometry

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.

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.

 

Undergauge Hole Causes Stuck Pipe

Undergauge hole can  happen when drilling in hard and abrasive formations where it wears down a drill bit. When the bit is undergauge because the abrasive formation wears a bit and stabilizes, a hole size becomes smaller. When the new BHA is run in hole, the new bit/BHA gets stuck into the undergauge hole section. Additionally, if coring is performed with a smaller core bit than the next bit, the new bit can get stuck at the top of the coring section.

Undergauge hole is caused by abrasive formations

Undergauge hole is caused by abrasive formations

The drill string gets stuck at the undergauge section

The drill string gets stuck at the undergauge section.

Warning signs when you get stuck due to Undergauge Hole

  • Drilling into abrasive formations.
  • A bit and stabilizers are undergauge.

Stuck identification for Undergauge Hole

  • This type of stuck pipe occurs only when tripping in hole.
  • Sit down weight suddenly increases.
  • The bit gets jammed off bottom.
  • Circulation can be established.

What should you do for this situation?

  1. This stuck pipe always happening while the drill string is being moved down, therefore you need to jar up with maximum trip load without applying any torque in the drill string.

Preventive actions:

  1. Properly gauge bit/stabilizer after it is pulled out so you will know the possibility right away.
  2. Do not stage weight in order to pass the tight spots. The more weight you put on top, the harder to free the pipe.
  3. If the undergauge bit/stabilizer is observed, you need to ream down at least 1-2 stands off the bottom.
  4. Reaming at least 1-2 stands above the top of the coring section.
  5. Trip in hole with controlled speed prior to going to possible problematic areas.

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.

 

Stuck Pipe Introduction

This topic will give you an overview of stuck pipe and how people classify stuck pipe.

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Definition of Stuck Pipe

 

Stuck pipe is a situation when the drill string cannot be moved from the well. The drill string may be partially moved and circulation & rotation may or may not be possible. Personnel on the rig must be able to identify the cause of stuck pipe in order to figure out the right way to free the pipe.

Stuck pipe categories

There are 3 categories of stuck pipes as follows:

Pack off and Bridging

Pack off and bridging are occurred when there is something in the wellbore, such as formation cutting, junk, etc. accumulating around the drilling string/BHA and that stuff blocks the annulus between the drill string and the wellbore. You should remember that either big or small debris can stick in the pipe.

According to statistics around the world, pack off and bridging is the most frequent cause of stuck pipe situations in the world. It normally occurs when the mud pumps are off for an extended period of time, such as when pulling out of a hole. It is quite a tough job to free the pipe in case of packoff or bridging and the chance of success is lower than differential or wellbore geometry sticking mechanism.

Differential Sticking

Differential sticking happens when drill string is pushed against permeable formations by differential pressure between hydrostatic and formation pressure. The frictional force between drill string and formation is so high that you will not be able to move the pipe. The differential sticking tends to easily happen when drilling through a depleted reservoir is conducted. Moreover, this stuck mechanism almost always happens when the drill string has  stopped moving for a long time.

Wellbore Geometry

Wellbore geometry stuck pipe mechanism occurs when the shape of the well and the bottom hole assembly (BHA) don’t match each other. Therefore, the drill string is not able to pass through that section.

Note: All of the details about stuck pipe mechanism will be described in later chapters.

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].