Design and select of resisting corrosion cement slurries by carbon dioxide for high temperature deep well

On the base of analyzing corrosion action process of oilwell cement by carbon dioxide at high temperature, effect law of corrosive conditions on corrosive depth were studied and effect characteristics of corrosive depth on the drop rate of compressive strength were analyzed. The basic composition of cement slurry was selected. The following conclusions are obtained: With the increase of temperature, CO2 deferential pressure and corrosion time, corrosive depth was increased. On the relationship of linear, logarithm and extract the square root between corrosive depth and corrosion time, temperature, CO2 deferential pressure, the corrosive depth prediction model was established. With the increase of corrosive depth, drop rate of compressive strength was increased for cement slurries without Resisting Corrosion Tampon Materials（RCTM）, when the cement slurries were added RCTM, compressive strength drop rate of corrosion cement stone were increased at early curing time, but decreased at later curing time. The resisting ability for cement corrosion by CO2 cloud be enhanced by reasonably designing composition of cement slurry, improving microstructure, increasing original compressive strength. No.6 cement slurry designed by this paper is effective for deep well cementing of temperature 120~150 ℃ to resist cement corrosion by CO2 in Daqing oil field.