页岩储层CO₂泡沫压裂液摩阻特性研究

Friction Characteristic of CO2 Foam Fracturing Fluid in Shale Reservoir

李松 桑宇 周长林 王业众 罗向荣

LI Song SANG Yu ZHOU Changlin WANG Yezhong LUO Xiangrong

CO2泡沫压裂液在管流等过程中的压力降计算关系到整个压裂施工过程的可靠性。模拟现场施工条件，通过室内管流实验研究了高温高压条件下CO2泡沫压裂液的摩阻特性，分析了压力、温度、泡沫质量和流速对CO2泡沫压裂液摩阻特性的影响规律。建立了CO2泡沫压裂液未发泡和发泡状态下的摩阻系数数学计算模型，预测了CO2泡沫压裂液在不同泵注排量下的管柱摩阻。结果表明，CO2泡沫压裂液摩擦阻力系数随温度升高、剪切速率和压力的增加而减小，随泡沫质量的增加而增大，当泡沫质量分数大于75%时，摩阻系数降低。压力对摩擦阻力系数的影响较小。通过摩阻系数数学计算模型，计算得到CO2泡沫压裂液在层流条件下具有较好的增黏效果，紊流条件下的降阻效果较好。相同排量下31/2″油管对应的摩阻小于27/8″油管的摩阻，CO2泡沫压裂的管柱应选择31/2″油管。认识和评价CO2泡沫压裂液摩阻特性对现场压裂施工设计具有重要意义。图15参19

The pressure slope calculation of CO2 foam fracturing fluid in conduit flow was the key to reliability of whole fracturing process，which influenced the effect of formation stimulation. The friction characteristic of CO2 foam fracturing fluid was investigated at high temperature and pressure by conduit flow experiment which simulated field condition，and the effect of pressure，temperature，foam quality，and flow rate on friction characteristic of CO2 foam fracturing fluid was analyzed. The mathematic model of friction resistance coefficient was established，and the friction resistance of CO2 foam fracturing fluid in turbulent flow was predicted. The results showed that the friction resistance coefficient of CO2 foam fracturing fluid declined with increasing temperature，flow rate and pressure，and increased with increasing foam quality. Once the foam quality exceeded 75%，the friction resistance coefficient would reduce. The effect of pressure on the friction resistance coefficient was not obvious. The calculating result of mathematic model of friction resistance coefficient indicated that CO2 foam fracturing fluid had viscosity increasing effect on the condition of laminar flow，and that had friction reducing effect on the condition of turbulent flow. On the condition of same delivery rate，the friction resistance of 31/2″ tube was less than that of 27/8″ tube，and 31/2″ tube was usually applied for CO2 foam fracturing. The investigation on friction characteristic of CO2 foam fracturing fluid was helpful to design parameters of field fracturing.

10.19346/j.cnki.1000-4092.2018.01.010