Abstract:The condensate reservoirs in an oilfield of Hainan Fushan exploration area, Petrochina, have problems of complex fault block structure, strong reservoir heterogeneity, poor contrasts between the layers, the developed thin interbeds, complex oil, gas and water relations, and high formation temperature, the reservoir fracturing effects are not obvious with the conventional fracturing fluid system. To improve the fracturing effect, the guar gum fracturing fluid system with ultralow concentration was developed which had the advantages of high temperature resistant performance, strong sand carrying ability, complete gum breaking, little damage to the reservoirs and low cost, the mass concentration of thickening agent is 3.5~5kg/m³, which is 30% to 50% less than the conventional guar gum, the temperature resistant capacity is up to 150℃, the liquid residue content is 30%~40% less than the conventional system formula with the same temperature, solving the problems of difficult sand fracturing, low fluid flow-back rate after fracturing and much damage to reservoirs of deep wells in high-temperature condensate reservoirs. Field application showed that stimulation results were significant after reservoir fracturing with this fracturing fluid system.