Multi-Component Cements for Sealing Casing Columns in Boreholes

Abstract

Ensuring proper and effective cementing of casing pipe columns in boreholes requires maintaining appropriate technological parameters for the developed slurry recipes. It is also necessary to use technology which guarantees effective displacement of the drilling mud for cement slurry injection into the annular space of the borehole. The most important factors that ensure high efficiency of drilling mud displacement by the cement slurry are, among others, the rheological properties of the liquids involved in the process of cementing the casing columns (drilling mud, cement slurry, buffer liquid). The introduced version of the European cement standard, PN-EN 197-1, includes new types of very economical multi-component cements CEM V/A and CEM V/B, which contain 20–40% Portland clinker with a relatively high content of hydraulic and pozzolanic constituents. They occur in the form of granulated blast furnace slag, natural as well as industrial pozzolans and silica fly ash from the combustion of hard coal. The article presents the results of laboratory tests on the technological parameters of both fresh and hardened cement slurries prepared on the basis of CEM V multi-component cement varieties A and B. These slurries meet the standard technological parameters to a demanding extent, which makes it possible to apply them to cementing columns of casing pipes in deep hole drilling. Their detailed properties can be modified by introducing other mineral additives and chemical admixtures to the cement slurry recipes.