Which of the following are types of drilling fluids?

The correct answer identifies a well-established category of drilling fluids, which are essential in the drilling process to facilitate various functions, such as cooling the drill bit, removing cuttings, and maintaining hydrostatic pressure.

Water-based fluids are commonly used in drilling operations due to their favorable properties, such as cost-effectiveness and environmental compatibility. These fluids primarily consist of water and can include additives to enhance their performance.

Oil-based fluids, on the other hand, are designed for specific applications where greater stability and performance are required under challenging conditions, such as high temperatures or pressures. They offer advantages such as reduced hydration of the formation and improved lubrication.

Gas-based fluids, typically involving the use of gases like air or nitrogen, are utilized in particular drilling scenarios, such as when drilling in unstable formations or for certain types of shallow well operations.

This combination of water-based, oil-based, and gas-based fluids represents the diverse range of drilling fluids that can be employed, depending on the drilling environment and specific needs of the operation. The other options listed do not accurately reflect commonly accepted categories of drilling fluid types, which is why they do not represent the correct answer.