All surfactants used in hydraulic fracturing adsorb a thin film on the surface of coal within its cleat structure. Foaming agents have been known to persist in produced fluids for long periods of time post-treatment. When methane gas trapped in the coal's matrix begins to desorb and flow through the cleat network in the presence of water and a surfactant film, foam bubbles can form blocking flow of gas to the cleat system and the propped fracture. The net effect is a decrease in the relative gas permeability. The direct result is less gas production.
A novel surfactant or foaming agent has been identified as being much less damaging to relative gas permeability. This paper documents the move from the laboratory to the field of this foaming agent in the first known field trial to validate its potential to improve gas production.