A ultra-high density salt torlerant cement slurry.

In western areas, when cementing high-pressure oil/gas layers or adjustment wells in mature oilfield, well blowout or gas channeling often occur. In an effort to avoid these problems, a ultra-high density salt tolerant cement slurry system composed of ferrilite powder, fluid loss reducer CJF-200L, dispersant FDN, retarder CJR-200L and suspending agent(micro silicate) was developed. Evaluation on the slurry system showed that, when prepared with both clean water and 10% NaCl solution, the slurry has stable properties, good fluid loss control, easily adjustable thickening time, and the cement stone exhibits high compressive strength. Stimulating tests onsite brought excellent results, and requirements of flowability, initial consistency, bump time, thickening time, fluid loss, free water and compressive strength were all satisfied. For the slurry of 2. 42 g/cm3, tank pressure of 0. 15-0. 18 MPa is enough for regular supply to get the density required, and for the slurry of 2. 60 g/cm3, the needed tank pressure is 0. 15-0. 18 MPa. All the data indicated the ultra-high density salt tolerant cement slurry is suitable for ultra-high pressure oil/gas wells cementing operation.