Salt water drilling mud is the drilling fluid that has salt water as base fluid. We normally classify type of saltwater by chloride concentration. The list below demonstrates how much concentration of salt for each type of salt water.
Brackish water: Brackish water is water that has more chloride content than fresh water, less than seawater and it typically contains between 5,000 to 30,000 mg of salt per liter.
Sea water: It is water from the ocean and it has a salinity of +/- 35,000 mg of salt per liter.
Saturated salt water: The saturated salt water or you may call as “brine” contained a lot of chloride content until it reaches the saturated state. It has dissolved salt of > 50,000 mg of salt per liter.
The salt water mud is typically used for certain reasons such as preventing hydrate in deepwater application, and drilling into salt formations. Moreover, especially offshore drilling, using the salt water (seawater) as base fluid greatly reduces and operational cost for logistic.
Typically, the brackish water and sea water are used as base fluid to make spud mud, polymer mud, etc. They are cost effective and practical for drilling operation. Moreover, they still act as a shale inhibitor. I personally use them to make several kind of water base mud such as spud mud, low solid non-dispersed mud, polymer PHPA mud, high disperse mud, KCL mud, etc. They can be utilized effectively and meet your drilling objectives.
source : http://www.drilling-mud.org/category/water-based-mud-drilling/
