Drilling mud has several important functions and one of them is hole cleaning which I will discuss today. Transporting cutting from the wellbore is fundamental part of drilling operation and you will not be able to successfully drill the well if you do not pay attention to this basic concept.
Nowadays people have more focusing on new technology about drilling mud and try to improve drilling fluid properties to achieve hole cleaning because many wells drilled in the world are more difficult which means hotter and deeper. Hole cleaning issue must be discussed since beginning in the planning phase. You need to ensure that mud formulas will give you good carrying capability and you also need to emphasize best practices to clean the wellbore. When implementing in the field, personnel show follow best practices when initially starting operation and adapt some practices to suit the operation. Please remember that best practices from other fields may not match your area.
It is very critical that good hole cleaning must be achieved because failure to effectively clean the wellbore will cause several drilling problems as listed below:
• Lost circulation
• Stuck pipe
• Hole pack-off
• High equivalent circulating density
• High torque and drag
• High over pull while pulling out of hole
• Decrease in rate of penetration
• Trouble while running casing and completion string
• Bad cement bond around casing and formation
Additionally, if you look at the production point of view, poor hole cleaning can also damage reservoirs and reduce wellbore productivity.
Ref: Importance of Hole Cleaning
topic on drilling mud