Custom-Engineered Solutions
for Underbalanced Drilling

Dry Air-Gas Drilling


This technique is commonly called "dusting” and is
used for drilling dry formations or where any water
influx is slight enough to be absorbed by the air-gas stream. Drilling through unstable formations with straight air is not advised, because air cannot carry wellbore stability additives. When water-saturated formations are encountered, problems occur:

• Wet cuttings form slugs that can plug pipe
• Intermittent passing of slugs effects surface 
   equipment
• Fluid build-up in the annulus can wet water-
   sensitive shales
• Borehole walls can become unstable

As the water influx increases, a number of warning
signs are observable at the surface:

• Loss of returns
• Pressure buildup
• Slugs of fluid at the blooie line

If the hole cannot be dried, mist drilling should be used.

Underbalanced Drilling

Air-Gas Drilling Techniques

Dry Air-Gas Drilling

Mist Drilling

Foam Drilling

Aerated-Fluid Drilling