Lost Circulation is not always a major problem; however, the procedure below should be followed when losses do occur:
1. Check surface equipment for leaks. If this fails to show any signs of leakage, proceed as usual in such cases, e.g. reduce mud weight if safe to do so.
2. When the level in the annulus is out of sight fill up the annulus with water to establish a fluid level.
CAUTION NEVER PULL OUT WHEN CIRCULATION IS LOST AND THE LEVEL CANNOT BE SEEN.
3. Do not slug the pipe with heavy pills for round trips when losses have been experienced, especially when static well conditions depend highly on a minimal overbalance. When losses occur during drilling in productive zones, first try decreasing the mud weight while still maintaining a sufficient trip margin, and optimise the mud rheology (e.g. lowest practical gel - yield - viscosity). If spotting of LCM pills is then still required, use acid-soluble materials such as "Snocal" to avoid formation impairment for future production.
Note: Minimising pressure surges by careful down-hole string handling, can reduce lost circulation problems.
Consider performing a casing pressure test using a packer, if the depth of the loss cannot be determined. This is to check whether losses take place through a hole worn in the casing. This is to be first discussed with Base.
Regularly check the ditch magnet for iron filings.
Also consider leaving out stabilisers, in order to avoid swabbing out LCM pills when moving the pipe, if it is anticipated that these pills will have to be spotted.
The depths where losses can be expected for each particular well, are usually mentioned in the Well Programme if such information is available.