STUDY AND APPLICATIONS OF LOW DENSITY FURNACE SLAG CEMENT SLURRY SYSTEM

A furnace slag cement slurry with density of 1.48~1.63 g/cm3 composed of slag instead of hydrated materials, slag activators and a few amount of conventional cement, bentonite and. floating beads was innovated in Changqing Oilfield. The slurry has following properties-fluidity 20 cm, thickening time (at 45℃, 25 MPa) 180 min, resistance to pressure (at 45℃) equal to 5.4~10.8 MPa. It has very good compatibllity with pure cement slurry and meets the requirements of rig-site operations. The four well practices demonstrated that the cementing with this low density slag cement slurry against the formations above the pay zones and that with pure cement slurry against the pay zones guaranteed a smoothened cementing engineering with super quality and less cost than low density burned coal residual powder cement slurry. The physical-chemical specifications of the furnace slag and its activators and its working mechanism were also discussed.