Stage Tool In Oil & Gas Well Cementing Full Guide
Stage cementing tool, consisting of stage collars and port collars, is placed within any types of casing string to provide an intermediate passage to the annulus (Fig. 1). The collars are generally made of match-grade steel. They may be available in special weight ranges to optimize strength and internal dimensions.

Stage cementing tool is generally used to:

- Protect weak formations from excessive hydrostatic pressure
- Cement widely separated zones
- Reduce mud contamination from cement.
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