Laboratory Studies on a Gas-check Cement Slurry

Gas-check cement was required for a high quality of oil well cement job in deep gas well in Qingshen area.A gas-check cement slurry was recently developed by introducing fiber and expansion agent into the latex cement slurry.This new cement slurry has a low rate of expansion and enhanced toughness.The concentrations of fiber and expansion agent were optimized through laboratory experiments.The addition of fiber at 0.5% and expansion agent at 1.5%~2.0% had no influence on the fluidity,free water and filtration of the cement slurry used,but the compressive strength of the cement set was increased.This cement slurry had an ideal right angle shaped consistency curve,with its thickening time being adjustable.Application of the cement slurry in 4 deep gas wells showed that no gas channeling was ever encountered,and a good cementing job quality was obtained.