If conventional LCM pills prove ineffective, a gunk squeeze may be attempted. The method utilises the swelling property of Bentonite in the presence of water. This method is not to be used for losses in reservoir section.
Allow four hours for the plug to set. The Bentonite will hydrate after the base oil is squeezed into the formation and it is allowed to come into contact with water from the mud.
1. Flush the cement pump and lines Thoroughly with diesel to remove all traces of water.
2. Prepare a gunk pill by dispersing 30 ppb of Bentonite in 25 bbl diesel.
3. Pump a 10 bbl diesel spacer downhole with the bit just above the lost circulation zone.
4. Pump gunk pill.
5. Follow this gunk mixture with another 10 bbl diesel spacer.
6. Proceed to displace to the bit using mud.
7. Pump simultaneously down drillpipe and annulus and apply a squeeze pressure of 100 - 300 psi.
8. Allow four hours for the plug to set. The Bentonite will hydrate after the base oil is squeezed into the formation and it is allowed to come into contact with water from the mud.