大川中沙溪庙致密砂岩储层支撑裂缝导流能力的影响因素OA北大核心

Objective Increasing the fracture conductivity of tight sandstone and thus improve the fracturing effect to increase and stabilize the production.Methods In order to investigate the adaptability of sand-added fracturing technology in the reforming of the Shaximiao tight sandstone reservoir in central Sichuan,the influence of proppant type and particle size,sand concentration and closure pressure,and fracturing fluid type on the fracture conductivity was investigated using the API fracture conductivity tester.Results The results showed that the proppant fracture conductivity of ceramic grains with the same grain size was greater than that of coated quartz sand and quartz sand,but the conductivity of coated quartz sand was least affected by closed pressure.The decrease of proppant conductivity of different combinations of grain sizes(1∶4,1∶1 and 4∶1)of 0.106-0.212 mm quartz sand and 0.212-0.425 mm coated quartz sand was more moderate compared with that of single proppant.The fracture conductivity of proppant combination 4∶1 was higher than that of the 1∶4 and 1∶1 combinations and approached that of the single proppant for 0.212-0.425 mm coated quartz sand at high closed pressure conditions.The increase in sand laydown concentration resulted in a significant increase in the infiltration capacity at low closed pressure.At high closed pressure,this effect gradually decreases.With 4∶1 proppant combination of 0.106-0.212 mm quartz sand and 0.212-0.425 mm coated quartz sand,when the closing pressure was 41.4 MPa,the flow conductivity tested with breaker fluid(prepared from fracturing fluid prepared with clear water)was 25.43％lower than that of 3 wt％KC1,and the flow conductivity tested with breaker fluid(prepared from fracturing fluid prepared from backflow fluid)was 58.34％lower than that of 3 wt％KC1.Conclusion The experimental results guided the selection of construction parameters such as fracturing proppant type,grain size,and sand spreading concentration in the field.They were applied in the field of tight gas reservoirs of the Shaximiao Formation in the central Sichuan Basin,obtaining better fracturing and production enhancement results.