同心蒸汽驱环空管汽水两相流压降分析计算

Analysis and Calculation on Pressure Drop of Steam-Water Two-Phase Flow in Annulus for Concentric Steam Flooding

垂直环形管内气液两相流压降是稠油热采同心蒸汽驱井筒设计的关键参数。基于前人压降理论,综合分析井筒散热及气液间相对滑移,建立垂直环空管内汽水两相流压降与井筒散热耦合模型,验证持液率及压降计算的准确性。编程计算水蒸气压力、干度及焓值沿井深方向的变化规律,并分析环管结构参数和质量流率对其的影响。结果表明:注汽内管外径减少,导致压力降低、干度及焓值上升;质量流速增加使压力降低、干度及焓值增加。

The pressure drop of the gas-liquid two-phase flow in the vertical annulus is a key parameter for the design of the concentric dual-tubing steam injection wellbore for thermal recovery of heavy oil. Based on the previous pressure drop theories, with the comprehensive analysis of wellbore heat dissipation and relative slip between gas and liquid, a coupling model of pressure drop of steam-water two-phase flow in vertical annulus and wellbore heat dissipation is established,to verify the accuracy of calculation of liquid holdup and pressure drop. Calculation code for the change law of steam pressure, dryness and enthalpy along the direction of well depth is compiled, and the effect of annular structure parameters and mass flux on them is investigated. The results reveal that the decrease in the outer diameter of the injection inner tube leads to a decrease in pressure and an increase in dryness and enthalpy;an increase in mass flux causes a decrease in pressure and an increase in dryness and enthalpy.