CO2泡沫压裂液在裂缝中的两相流动研究

CO2泡沫压裂液具有油层伤害低、滤失量小、返排能力强等特点，不仅能在高渗透地层压裂中应用，在低渗透油气田的开发中也起到了关键性的作用。通过矩形裂缝实验系统研究了不同流体特性、不同流速、不同泡沫干度条件下CO2泡沫压裂液的两相流阻力特性，提出了两相流阻力的泡沫干度修正系数。在低粘度下，CO2泡沫压裂液在矩形裂缝中的两相流动阻力随流速和泡沫干度的增大而增大；在高粘度和高泡沫干度下，两相流阻力特性曲线相当于低流速区阻力特性曲线沿流速坐标轴向高流速区的平移，表明在该条件下的CO2泡沫压裂液在裂缝中能更好地满足高摩阻悬砂、低摩阻返排的压裂工艺要求，为泡沫压裂液性能的评估以及合理选择钻呆压裂参数提供依据。

Study on Two-Phase Flow of CO2 Foam Fracturing Fluid in Fissures

CO2 foam fracturing fluid is characterized by its low formation damaging effect, reduced filtration loss and increased flowback therefore it can be applied not only in fracturing operation in high permeability wells but also in low permeability wells. This paper described the research work conducted on the two phase flow characteristics at varied flow rate of foam fluids of different driedness and presented a rectification coefficient of foam driedness for calculation of two phase-flow resistance using a rectangular fracture testing system. In the low viscosity range, the two-phase flow resistance increases as the flow rate and foam driedness increase. In the range of high viscosity and high foam driedness, the two-phase flow characteristic curve is just like a parallel one to the curve in the low flow rate region moved along the flow rate coordinate and this demonstrated that CO2 foam fracturing fluid can meet the requirements of the fracturing technology on high suspension ability of sand at high resistance and good flowback character at low resistance that may provide references for evaluation on the properties of the foam fracturing fluid and rational selection of the parameters of fracturing operations.