KCl is added to cement slurries for application in water-sensitive shales and clays. By preventing clay swelling, it helps improve the cement/formation bond. For these applications, KCl is effective at temperatures between 50°F and 380°F (10°X and 193°C). Typical KCl concentrations are 2 to 5% by weight of water (BWOW). KCl slightly decreases the effectiveness of fluid-loss additives and dispersants, and it slightly accelerates cement slurries.
The benefits of using KCl include:
- Helps control clay swelling in the presence of water and helps minimize fines migration.
- Helps promote a better bond between the cement and the formation.
- Slightly accelerates slurry setting time.