多元热流体吞吐水平井热参数和加热半径计算

多元热流体吞吐已成为海上稠油的主要热采方式。为优化注入参数,对水平井井筒沿程热力参数和加热半径进行预测。考虑井筒流动与油层渗流的耦合,建立水平段井筒中多元热流体流动和换热的数学模型。计算多元热流体水平段沿程压力、干度和加热半径分布,分析气体含量、注入速度等因素的影响。结果表明:在注入过程中,水平段沿程压力和蒸汽干度逐渐下降,加热半径呈先下降后上升的"U"型变化;保持其他条件不变,适当降低非凝结气体含量、增大注入流量,有助于扩大加热范围。

Modeling of thermodynamic parameters and heating radius for multiple thermal fluid stimulation in horizontal wells

Thermal stimulation via injecting hot fluids in horizontal wells has become a main thermal recovery technique for offshore heavy oils. In order to optimize the injection parameters, it is necessary to predict the thermodynamic parameters and heating radius along horizontal wellbore. Mathematical models, considering flows in wellbore (pipe flow) and in oil reservoir (flow in porous media) were established to simulate the process of hot fluids injection and heat transfer in horizontal wells. The hot fluids used compose of water and non-condensed gases. The pressure, temperature and steam quality of the injectants along the horizontal wellbore can be calculated. The effects of injection rate and the fluid compositions on the thermodynamic parameters and heating radius along the horizontal wellbore were investigated. The simulation results show that the pressure, temperature and steam quality of the injectant will reduce gradually along the wellbore during the process of injection, while the heating radius along the horizontal well decreases initially and then increases gradually. Increasing the injection rate and reducing the gas content can increase the heating radius.