Well ballooning (wellbore breathing or micro fracture)

This topic describes about well ballooning. You may hear several terms besides well ballooning as wellbore breathing or micro fracturing phenomenon.

What is well ballooning?

The well ballooning effect is a natural phenomenon occurring when formations take drilling mud when the pumps are on and the formations give the mud back when the pumps are off.

What is mechanism of well ballooning?

While pumps are on, if Equivalent Circulating Density (ECD) exceeds formation fracture, micro fractures are created and drilling mud will lose into small induced formation fractures. The micro fractures can be propagated and it may cause a lot of mud volume losses down hole. Micro fracture will not cause severe losses or totally losses.

When pumps are off, the ECD will reduce because annular pressure loss becomes zero. The induced micro fractures will close and the drilling mud will flow back into a wellbore.

The ballooning can happen into any weak formations, not only at the casing shoe. Sometimes, mud flow back from formations can bring gas or formation water with the mud therefore you may see gas peak or mud contaminated with water while circulating bottom up.

Reference books: Well Control Books

 

Related Post

Effect of Frictional Pressure on ECD while Forward... You may now already that the equivalent circulating density is a combination between current mud weight and frictional pressure. However, this post I ...
Shut-In Procedure while Drilling VDO The steps , called "3S" shut-in procedures, demonstrate how to properly shut the well in while drilling. You can learn about it via this VDO ...
How to Predict Formation Pressure Prior to Drillin... Formation pressure can be predicted from 3 information sources prior to drilling as follows; 1. Seismic Data Seismic is the way to predict forma...
Oilfield Acronym Spreadsheet You may get confused when you see a lot of oilfield acronym used for oil and gas industry so we would like to make your life easier by collecting oilf...
Share the joy
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  
  •  

About DrillingFormulas.Com

Working in the oil field and loving to share knowledge.
Tagged , , . Bookmark the permalink.

2 Responses to Well ballooning (wellbore breathing or micro fracture)

  1. Pingback: How to Identify Well Ballooning‎

  2. What are the techniques involved in cementation of wells where Balloning problem exists

Leave a Reply

Your email address will not be published. Required fields are marked *