What Does Pneumatic Drilling Fluid Mean?
Pneumatic drilling fluid (or gas-based mud; air-based mud) is used to drill in areas where the use of conventional drilling fluids is not feasible. They are used to drill in depleted zones, areas with low reservoir pressures, and where a loss of circulation is predicted.
Pneumatic drilling fluid basically consists of dry gas, such as air, natural gas, carbon dioxide or nitrogen, and is best suited for formations that have less amount of water.
Trenchlesspedia Explains Pneumatic Drilling Fluid
Pneumatic drilling fluids are useful where conventional drilling fluids can cause complications and damage to the formation. It requires a few basic chemicals such as surfactants - as detergents or foaming agents, corrosion inhibitors and drying agents.
Formation damage can be caused by invasion of pore spaces by mud filtrate and solid particulates, clay hydration within the reservoir, flushing of hydrocarbon, the formation of chemical precipitates within the reservoir, and by emulsion blocking.
Formation damage can happen due to an overbalance of pressure resulting from chemical incompatibility between the invading filtrate and the reservoir fluid, and high hydrostatic pressure of the mud column. Since pneumatic drilling fluid does not hydrate the clay and form precipitates, the damaging causes are diminished considerably.