Many gas reservoirs or "payzones" experience very low bottom hole formation pressures and gradients, and are marginal producers when drilled with a fluid based drilling system.

The economics of producing these wells becomes greatly hampered when done with conventional drilling fluids.

The use of air to drill thru these payzones prevents skin damage and overbalancing, both common with mud. The major advantage is the sensitive payzone is not exposed to any fluids. In addition, an inexpensive flow test can be easily conducted without pulling the drillstring out of the wellbore.

The "payzone" systems supplied by Total Wellhead & Rental Tools are readily adaptable to drilling and workover rigs to drill out of a cement shoe and into the payzone.