Abstract: The property of class G cement mainly affect the performance of the cementing quality. The property of four different class G oil well cement was tested and the effect of these property on the performance of the cementing slurry, such as thickening time, rheology and compressive strength was studied. The results show that the following items. The fineness and mineral composition of the class G oil well cement mainly affect the rheology of the cement slurry. The aluminate phase ( C3 A+C4 AF) is the key reason of the compatibility of cement and additive. The type and content of gypsum severely affect the thickening time of the cementing slurry.

Key words: oil well cement;thickening;rheology