Design and application of high density cement slurry in Shengtuo region

Research on high density salt tolerant cement slurry is carried out to solve the problems of the high initial layer pressure of oil and gas wells and the gas migration while cementing in Shengtuo region.According to the principles of high packing and granularity,microsilica and iron ores are used for grain composition,iron ores and additives produced by the World Company are selected to develop high performance and high density cement slurry.What’s more,laboratory evaluation on the stability,thickening time,preventing gas-channeling properties,and rheological properties of this cement slurry is conducted.The experimental results show that the high density cement slurry has properties of stable sedimentation,adjustable density ranging from 1.90 g/cm3 to 2.60 g/cm3,no free liquid,good rheological property,low fluid loss,high strength,adjustable thickening time,and excellent preventing gas-channeling properties.It has been successfully applied to Tuo720 well of Shengtuo region as well as well cementing operation of high pressure oil and gas reservoirs in Shengli Oilfield and Xinjiang,etc.,The field application shows that the indexes of the system such as rheological property,initial consistency,fluid loss,thickening time,and compressive strength fulfill the demand of construction.Good cementing results have been achieved and it is possible to be more popularized and applied.