Non-Aqueous Fluid (NAF)
Definition - What does Non-Aqueous Fluid (NAF) mean?
Non-aqueous fluid (NAF) is a drilling fluid that is not water-based. Commonly used NAF systems are diesel oil, mineral oil, or invert emulsions that are based on synthetic fluid.
In NAF systems, the water phase is emulsified in a continuous oil phase, also known as a water-in-oil emulsion or invert emulsion. These drilling fluids adapt easily to variation in pressure, temperature, and wellbore conditions, and are stable when faced with high temperatures, soluble gasses, and high electrolyte concentrations.
Non-aqueous fluid is also referred to as non-aqueous drilling fluid.
Trenchlesspedia explains Non-Aqueous Fluid (NAF)
Non-aqueous drilling fluid is used for drilling sections of oil and gas wells where problems such as wellbore instability, shale sloughing, and stuck pipe are encountered.
Their superior performance (compared to water-based drilling fluid) when faced with technical challenges in offshore drilling, has made NAF a necessary asset. NAF has the required high performance, lubrication, and stability that is required in conditions such as directional drilling and where extended reach is required.
However; since these fluids dissolve formation gas, early gas detection and thereby well control can be challenging, especially in deep offshore wells where large amounts of gas can be dissolved under conditions with high pressure and temperature.