calcium carbonate plug

1. n. [Well Completions]
A temporary plug formulated with graded granules or flakes of calcium carbonate that are generally circulated into place as a slurry and allowed to settle out. Calcium carbonate plugs commonly are used to isolate lower production zones, either to enable a column of well control fluid to be placed, or to provide some protection for a lower zone while treating upper zones. Because of their high reaction rate with hydrochloric acid, calcium carbonate plugs are easily removed using common acidizing materials and equipment.