液态 CO2压裂是采用液态 CO2作为压裂液进行增产改造的工艺技术，对储层无伤害，可替代水基压裂液，近年来在致密气藏、页岩气藏等非常规气藏的开发中受到广泛关注。液态 CO2压裂管流摩阻的合理预测及适于工程应用计算模型的建立对于压裂施工设计具有非常重要的意义。采用高温高压流体循环回路系统地测试了模拟施工条件下液态 CO2管流特征，液态 CO2粘温特征研究表明温度的升高会降低液态 CO2粘度，而压力的升高会增加液态 CO2的粘度，温度对液态 CO2粘度的影响相比于压力的影响要更为明显。同时实验测试了不同温度、压力条件下液态 CO2管流摩阻，表现为温度的升高会降低液态 CO2管流摩阻，压力的升高反而会增大管流摩阻，建立了液态 CO2管流摩阻系数与雷诺数之间的布拉修斯形式的计算模型，该模型与现有经验公式相比具有较高的计算精度以及工程实用价值。%Liquid CO2 fracturing technology has received widespread attention in that the use of liquid CO2 as a fracturing fluid has no damage to reservoir in tight and shale gas development in recent years. Pipe flow characteristics of liquid CO2 were studied experimentally under fracturing treatment condition,the vis-cosity-temperature characteristic results shown that the promoting effect of temperature on CO2 molecule free motion was greater than the inhibiting effect of pressure,and the effect of temperature on liquid CO2 viscosity was more obvious than that of pressure,and the calculation model of liquid CO2 effective viscosity was established by fitting the experimental results. Moreover,the pipe flow friction of liquid CO2 was tested experimentally under different temperature and pressure,and the results shown that the increasing temper-ature would decrease the liquid CO2 pipe flow friction,however,the increasing pressure would increase the friction,and the calculation relationship between liquid CO2 pipe flow friction factor and Reynolds number was established,which had a high precision compared with other empirical models and had practical wor-thiness.
展开▼
