D- Oil Base & Synthetic Mud

((Is that mud with oil as its continuous phase with not more than 1 – 5% water)).

Advantages of oil base mud:-

1- protection of production horizon,

2- drill water sensitive formations; salt, clays..

3- allowing longer bit runs than water base mud of the same weight.

4- less viscosity problems in deep hot holes.

Disadvantages

Cleaning Drill Pipe