High-density cement slurry

摘要

Hydraulic high density cement slurry, especially for cementation of oil/gas-wells. The slurry contains 30-45 weight % microsilica based on the cement weight and water to a density of 1.9-3.5 g/cm3. If desired there can be added dispersant, retarder and weighting agent. Microsilica acts as a fluid-loss preventing agent. The addition of microsilica prevents strength retrogression at temperatures above 120 DEG C. and acts as a mechanical stabilizer for the cement slurries. A method for production of the cement slurry is also described.