Optimization Design and Performance Evaluation of New Type Low Temperature Early Strength Cement Slurry

摘要

In recent years, exploration and development of gas hydrate in deepwater has become more and more important. The problems encounteredin gas hydrate cementing are low temperatures, short sealing segment,and large annulus. The strength of normal portland cement developstoo slowly at low temperatures to support the wellhead.With compounds of organic and inorganic materials, the reinforcedagent is developed to improve the strength of portland cement. Theexpansion agent and low density lightening material were optimized tomeet the low temperature requirement.New type low density low temperature early strength cement slurry isdesigned based on high packing theory. PVF (packing volume fraction)of the five-element system is more than 0.80. The slurry density can beregulated between 1.30g/cm3 and 1.50g/cm3. When the thickening timeof the cement slurry is more than 150 minutes at 30°C, the compressivestrength of cement can reach 6.5MPa after 24h of curing at 4°C. Thecement slurry has excellent comprehensive performance such as: goodrheology and good stability.