Problem - Gypsum or Anhydrite
Symptoms
High viscosity, high flat gel strengths, and increase water loss, filtrate calcium and sulfate.
Solution
Pretreat for small quantities or remove chemically with soda ash. For drilling massive anhydrite change to mud
which will tolerate anhydrite.


Problem - Salt Rock
Symptoms
High viscosity and high gel strengths; increase in water loss and salt content. Grainy appearance to mud.
Solution
Adjust mud properties with organic thinners and water loss control agents, or convert to saturated salt system.