A New Nanometer Accelerating Early Strengthen Agent for Oil Well Cement

Accelerators used in conventional oil well cement cause casing to corrode, viscosify the cement slurry and cause the cement slurry to have weak early strength. To solve these problems, a new nanometer accelerating early strength agent A-1 is developed through solution synthesis. Study on the general properties and working mechanisms of A-1 indicate that A-1 can both improve the rheology of cement slurries and shorten the thickening time of cement slurries at medium and low temperatures, significantly accelerating the development of the strength of the set cement. The thickening time ratio reaches 0.33, the time for strength development can be shortened by 50%, the 6 h compressive strength can be 5 times higher than that of the base slurry, and the later strength improvement rate can still reach 29%. Moreover, this nanometer accelerating early strength agent can significantly shorten the transition time of the gel strength of cement slurries, showing good anti-channeling performance. Microanalysis results show that the nanometer accelerating early strength agent can alter the micromorphology of set cement through nucleation template effect, thereby accelerating the hydration of set cement, making the set cement denser and hence improving the mechanical performance of set cement.