Using gradient multi-setting cement slurry in long isolation section

Gradient multi-setting cement slurry system can take the place of double stage cementing in long isolation sections in certain degree, and it displaces many advantages.An effective cement system which has different density and consistency gradient was developed for different cementing conditions.Field using in two wells showed that the system has such properties as preventing the happening of gas channeling, lost circulation and casing corrosion.It can decrease cementing pressure, reduce costs of drilling and cementing, and cut down the construction cycle, etc..Excellent cementing qualities were achieved in the two wells using this cement slurry system.