Horizontal air drilling

From Wikimarcellus

Drilling with air instead of mud has a strong economic advantage because of the increased rate of penetration. Since the total cost of drilling is related to the time it takes to do it, there is clear advantage to minimizing the time to finish drilling wells. Air compressors used for air drilling are still quite expensive. Nevertheless, air drilling is a cost efficient, thoroughly proven technology and may be rapidly deployed.

When it comes to using air for horizontal drilling one disadvantage is the lack of any Measurement-while-drilling (MWD) tool. There is an electromagnetic MWD which works in an air environment, but there are reliability issues with the device.