I have the opportunity to discuss a wide variety of drilling scenarios and downhole issues around the world. I am always surprised when I ask, “Did you try drilling with foam?” and the driller says, “No, foam is too complicated.” Ironically, that statement has come from both mud drillers and air drillers. Foam drilling combines the best characteristics of both air and mud drilling. Drilling foam increases the ability to lift cuttings with air, while creating borehole stability similar to mud. As drilling formations change, the color of the foam will also change giving a key indicator of geological changes to the driller. Foam does not have to be complicated if you follow these four guidelines.
Foams allow a rig operator to lower the required air volume from the compressor to lift cuttings. The goal with foam is to drill deeper boreholes with a smaller compressor. However, there is a difference between using household or industrial soap and an NSF-certified Standard 60, designed for groundwater approved foaming agents. First off, NSF-approved drilling fluids are designed to prevent groundwater contamination; non-NSF approved soaps can contain phosphates, which are a known nutrient source for bacteria. Maybe you are thinking, “I am not drilling potable water wells and I do not need to worry about NSF-approved materials.” If that is the case, you need to reconsider and understand we are all responsible for protecting our groundwater. Yes, non-NSF-approved soaps can create bubbles, but not all bubbles are created equal. NSF-approved foams for drilling are engineered with a specific job in mind: to create a tiny, strong bubble capable of withstanding rigorous downhole conditions and carry drill solids from the bit to the surface.