Citric Acid

It is commonly used as a pH control to reduce alkalinity and also plays an important role in transporting cuttings and removing calcium from drilling fluids. It can also help reduce the need for water and the backlog of oil well cements.
Citric acid in drilling gas and oil wells is used to neutralize cement in mud. It removes calcium ions from the drilling mud.
It helps to reduce the level of hydrogen (pH) in drilling mud and has anti corrosion properties. Reduces the risk of polymer mixing (xanthan gum, etc.) by interacting with equipment alloys and prevents the breakdown of highly molecular polymer networks during mixing.
It also acts as a polymer stabilizer.