Microblock® is a liquid cement additive made from a finely divided, high surface-area silica. It can be used as an extender for lightweight cements and a compressive-strength enhancer for low-temperature, lightweight cements. This product also imparts thixotropy to some cement slurries and acts as a low-temperature accelerator for salt slurries. Microblock cement additive can be used in wells with bottomhole circulating temperatures (BHCTs) between 60°F and 400°F (16°C and 204°C). It can help prevent high-temperature strength retrogression. However, an additional retrogression additive should be included in cementing designs for temperatures above 280°F (138°C). Because Microblock cement additive imparts thixotropy to the slurry, it can help control lost circulation and gas migration. In addition, this product can provide a degree of fluid-loss control.
Microblock® cement additive is a product from Elkem AS. Microblock is a registered trademark owned by Elkem AS.