2. Rheological properties of cement paste with ZOC-F44S dispersant

The rheological parameter of cement slurry is an important index to evaluate the drag reduction performance of dispersant. The workability and pumpability of cement slurry can be changed by adding dispersant. Under the standard water cement ratio, the rheological parameters of cement slurry, such as yield value, plastic viscosity, flow pattern index and consistency coefficient, are usually tested. The rheological properties of cement slurry with single addition of ZOC-F44S oil well cement dispersant under different conditions are shown in Table 3. 

Table 3 Effect of ZOC-F44S dispersant on rheological parameters of cement slurry

 No.   Dosage of     n               k(pa.s)          u(p)              ts(pa)

ZOC-F44S (%)  30℃   60℃   30℃   60℃     30℃   60℃     30℃   60℃

1    1.6         0.72     0.63      0.18   0.22   0.0255  0.0165   2.81   2.81

2    2.0         0.81    0.88   0.072   0.039   0.0195  0.0177   1.28   0.664

Table 3 shows that the rheological properties of the slurry can be effectively improved by adding the ZOC-F44S dispersant into the well cement. When the temperature increases, the agglomeration of cement particles caused by the rapid hydration rate can be eliminated by the dispersant of ZOC-F44S. It is shown that the structural stress of cement slurry is significantly reduced, thixotropic structure is weakened, and the plastic viscosity is small. Meanwhile, the cement slurry approaches power law fluid, and the n value tends to 1 obviously.