注蒸汽水平井井筒内参数计算新模型

注入蒸汽在水平井筒内流动时,蒸汽沿着水平段的质量流量越来越小,且加速度压降不等于零,导致蒸汽的物性参数发生变化,而蒸汽物性对井筒内蒸汽的沿程参数分布有较大影响。依据质量守恒和能量守恒,建立了注入蒸汽干度沿水平段的变化方程,利用动量守恒原理,推导了沿水平井筒的蒸汽干度分布和压力分布计算公式,构建了摩擦力做功、湿蒸汽混合物密度、水平段吸汽量和井筒与油层之间的热传递计算模型,模型同时考虑了变质量流与蒸汽PVT参数的变化对计算结果的影响,采用按压力增量迭代的计算方法对模型进行求解。实例的模型计算结果与油藏数值模拟结果对比表明,新模型具有较高的计算精度。

A NEW PARAMETER CAUCULATING MODEL FOR STEAM FLOODING HORIZONTAL WELLBORE

When steam flows in horizontal wellbore,the mass flow rate will decrease with steam draining into the formation.Acceleration pressure drop will cause the change of steam physical parameters,which play an important role in the distribution of steam properties.Based on the rules of mass conservation and energy conservation,a model for steam quality variation along with the horizontal section length is built.Pressure drop and temperature distribution of injected steam along horizontal wellbore are deduced by using the principle of momentum conservation,and some models such as work done by friction,density of wet steam mixture,amount of steam absorption and the heat transfer calculation model between wellbore and formation are built,and the models are solved by the method of pressure increment iteration.The comparison between examplebased calculation results and reservoir numerical simulator shows that the new model has a higher accuracy.