Emergence of nano silica for oil and gas well cementing: application, challenges, and future scope.

Nanotechnology has opened up a plethora of opportunities and has acquired extreme importance in a myriad of fields to produce enhanced materials. Their special properties make them sustainable for industrial purposes. One of the most crucial processes in the petroleum and geothermal industries is cementing. Various classes of Portland cement are used according to API classifications. The conventional Portland cement fails to perform its function at high pressure and high temperature (HPHT) conditions. Hence, various admixtures are used to improve its properties. HPHT conditions not only have a bad impact on Portland cement by affecting its rheological properties but also reduce its strength, porosity, and permeability. So, additives like nano silica are used to improve its properties. Better compressive strength, low porosity and permeability, higher yield stress, and reduced setting time are some of the major properties that improve by the use of nano silica. This paper discusses in detail the different types of cement, cementing processes, failure of Portland cement, and effect of nano silica as an admixture on the compressive strength, rheology, porosity, and permeability of the cement. Furthermore, the upcoming challenges in cementing are discussed along with future potential in this field.