Research on cement recipes for CCS application

Abstract

The technology of $CO_2$ sequestration is connected with the necessity of drilling wells, which construction is adapted to aggressive $CO_2$ rich environment. Recipes of cement slurries, used nowadays in carbohydrates production wells, are prepared without considering corrosion occurrence caused by affection of acidic environments originating from carbonate acid radicals. Although increased resistance to sulfates is typical for these cements, this does not guarantee any resistance to corrosive effects of $CO_2$. Density, fluidity, filtration, Marsh Funnel viscosity and rheological parameters measurements (with a twelve-ranged viscometer FANN) were carried out. Using Rheosolution Software, a proper rheological model for each recipe was matched. Corrosive effect on cement rock was obtained through keeping samples in pressure tanks containing compressed $CO_2$ for the period of 180 and 360 days. Directly after taking the samples out of the tanks, flexural and compressive strength tests were carried out with the use of hydraulic press. The results were compared and differences between the samples from $CO_2$ and samples taken from water environment according to API recommendations were presented. The corrosion effect on the samples from both environments was presented with microscopic images. Lengthening of the slurry thickening time and improvement of the slurry fluidity were obtained thanks to adding the third generation superplastifier produced by BASF Polska Sp. z o.o. As a research result a slurry recipe of the best strength has been developed. It can be used for proper sealing in $CO_2$ sequestration well technology.