Lost Circulation Material In Drilling
Formation losses usually account for most of the additional costs when actual drilling fluid costs exceed estimated figures, which is why so much effort goes into preventing down-hole losses in the first place. If offset data is known, then wells can be designed to isolate lost-circulation zones behind casing before drilling deeper formations that require higher mud densities. However, this is not always possible and a range of Lost Circulation Material (LCM)
https://bit.ly/3Hxbd61