Research and application of high density guar gum fracturing fluid system

High pressure oil and gas reservoir hydraulic fracturing is a difficult problem in Blocks J29 and C71 in Huabei oilfield. Aiming at this, a high density fracturing fluid system was developed by choosing sodium bromide and sodium nitrate as mixed weighting agent. Research showed that the density of this fracturing fluid can adjust between 1.20~1.55 g/cm3; And its viscosity is more than 100 mPa·s after 90 minites shearing under the conditions of temperature 160 ℃ and shear rate 170 s?1. 4 wells field application in Huabei oilfield has showed that, compared with common fracturing fluid, the construction output increases 1.0~1.5 m3/min with the high density fluid, and proppant concentration climbs 5~16 percentage point with the decresing of well head pressure in 7~15 MPa. The fracturing effect significantly improves compared with wells in adjacent block.