Experimental design of a well cement slurry for rapid gel strength development

Hydration of calcium sulfoaluminate cement (CSA) yields mainly ettringite that supports high early -age strength. The hydration characteristics of CSA can help to control gelation of a Portland cement slurry such that fluid migration is mitigated. This paper reports on the performance of well cements incorporated with CSA and gypsum on gel transition time and Right-Angle-Set (RAS) property for utilization in plugging oil wells. Rapid gel strength development is highly dependent on ettringite formation. It is observed that gel transition time shortens with increasing additions of CSA. RAS property is more evident with higher dosage of CSA regardless of retarder content. (C) 2018 Elsevier Ltd. All rights reserved.