What type of cement is not acceptable for mixing seals?

The selection of dry cement with water as the inappropriate choice for mixing seals stems from the fundamental requirements for effective sealing materials in drilling applications. When creating a seal, the cement must achieve the right consistency and bonding properties to ensure it effectively bonds and fills gaps. Dry cement lacks the liquidity needed for proper mixing and application; when combined with water at the point of use, it may not achieve the desired properties necessary for a reliable seal, including workability and adhesion.

Focusing on the other options, wet cement without additives can successfully achieve the necessary bonding and seal characteristics, as it is mixed to the appropriate consistency for application. Loose gravel cement is typically not used in sealing applications due to its inability to form a solid, impervious barrier, while thickened epoxy cement is often recommended for demanding sealing situations because of its superior adhesion and durability against environmental factors. All these alternatives provide properties that align better with the requirements for effective sealing compared to using dry cement mixed with water.