Which mineral having wall-building property, thus used in drilling oil wells

A. Bentonite

B. Kaolinite

C. Smectite

D. Illite

Answer: Option A

Solution(By Examveda Team)

Bentonite is a mineral having wall-building property, thus used in drilling oil wells. The bentonite in the flush fluid lubricates and cools the cutting tools while protecting against corrosion. As the drilling fluid generates hydrostatic pressure in the borehole, it hinders fluid and gas penetration.