The effect of cementing additives on the rheological properties, thickening time and compressive strength in drilling operation

Plastic viscosity (PV), yield point (YP), fluid loss volume, thickening time, and compressive strength of cement are the main parameters that are necessary for a successful operation. In this study, 25 tests were done to design different slurries and find the effect of various additives, including extenders (bentonite and sodium silicate), accelerators (calcium chloride and sodium chloride), retarders (calcium lignosulfonate and CMHEC), and fluid loss controller (FLC). Calcium chloride provides acceptable results up to 6% by the weight of cement. For more than 6%, it provides unpredictable results. The sodium chloride in high concentrations (30%) acts as a retarder. Calcium lignosulfonate slows down thickening timeless than CMHEC, while CMHEC can retard the slurry more and increase the closing time. The ratio of the increase in slurry setting time to the increase in calcium lignosulfonate is almost linear while for CMHEC this is not the case and this increase increases nonlinearly. addition of FLC on cement water causes water to be retained in the slurry system and this causes the increase of this additive in the slurry to increase the setting time of cement and reduce its short-term strength (24 hours).