Abstract: In order to create long fractures and propped fracture height effectively,and improve the effect of fracturing,a combined sand fracturing technique was developed.Based on the analysis of the effect of fracture width and fluid density on proppant migration trend,we determined sand adding order from small size to large size and from high density to low density.Comparing different proppant ratio combinations in conductivity test,it was found that increase in sand size and proportion of low density proppant can raise fracture conductivity.This technique has been applied in Well L3,in which 20 cubic meters of 30/50 mesh 1.75 kg/L ceramsites was added first,followed by 30 cubic meters of 20/40 mesh 1.60 kg/L ceramsites.Net pressure matching and analysis after fracturing treatment show that hydraulic fracture length reaches 196.8 m and fracture height reaches 42.5 m meeting the design requirements.Well L3 produced 5.6 t/d of fluid and 3.2 t/d of oil after fracturing initially.The field operation shows that this technique can create long propped fractures and fracture height effectively,providing technical reference for fracturing in similar thin interbedded reservoirs.