Research On Well Cementation Technology In DaQing Block Of Qaidamensis

High pressure gas bearing reservoir and saline aquifer existed in DaQing block of qaidamensis, in this block, the common cement slurry couldn't satisfy the well cementation's demand, its complicated geological structure bringed huge difficulty for well cementation.Through the in depth study for the geologic characteristic in qaidamensis, the high density cement slurry system which had salt-resisting and channel-resisting ability was developed. This system had good channel-resisting ability and could meet multi-pressure layer system's cementation demand. The cement intensity was affected very little by the temperature's changing, and this system had long thickening time, good stability, high compressing strength, good rheological property and good salt-resisting ability, its displacing efficiency was very high. The flushing performance of the segregation liquid was very well. The segregation liquid's compatibility removed the emergence of coagulation, deposition and thickening, its salt-resisting ability is very well ,the segregation liquid had two effects: flushing and isolating. The difficulty encountered in cementation in the DaQing block of qaidamensis was resolved successfully by using the high density and salt-resisting cement slurry system and the segregation liquid, the effectiveness was very well.