The secondary effects of lignosulfonate cement retarder on cement slurry properties

The primary function of retarders in cement slurry design is to increase the thickening time at higher temperature to allow time for placement of the liquid slurry. This has been the focus in the oil Industry on cement slurry design using retarders. However, test results from this research work using different retarder concentrations indicated that not only the thickening time was affected but the compressive strength, rheological as well as the free fluid properties. Increasing retarder concentration not only resulted to increase in thickening time, but a decrease in both rheological properties and early strength development as well as increase in free fluid results. It is therefore imperative that to optimize a cement slurry design to meet up with design objectives and all boundary conditions, the choice of optimum retarder concentration is critical.