Expandable Geopolymers for Improved Zonal Isolation and Plugging

Generally, the expansion of cementitious materials has been regarded as a promising avenue for better sealability. The sealability performance of an expanding geopolymer is compared to an expansive commercial cement in terms of the shear bond strength and the hydraulic bond strength at curing conditions of 25°C and 34.5 bar. A Neat Class G and a neat geopolymer were characterized alongside its corresponding expansive versions. The impact of these expansive agents on cement and geopolymers is evaluated in terms of linear expansion using the annular ring test. In terms of its performance for P & A operation, the push-out test was used to characterize the shear bond strength between the casing-cement interfaces, whereas the hydraulic bond strength is measured with a custom-made setup which eliminates any pressure and thermal shocks. These materials were characterized in terms of its shear bond strength, hydraulic bond strength and linear expansion. The shear bond strength of Neat G and expansive cement were estimated to be 22.37 bar and 22.76 bar respectively. Whereas that of the neat geopolymer and expansive geopolymer were recorded at 7.47 bar and 10.14 bar respectively. On the basis of the hydraulic bond strength, expansive cement had the highest followed by expansive geopolymer. Both the neat recipes were observed to have the same values in terms of the hydraulic bond strength. This study reveals that geopolymers can be deployed as an alternative to Portland cement upon optimization.