多点注汽水平井井筒出流规律数值模拟

Numerical simulation of the outflow performance for horizontal wells with multiple steam injection valves

基于多点注汽水平井管柱结构,考虑注入蒸汽在水平井筒内的变质量流特性及注汽阀节流压差的影响,建立了多点注汽水平井井筒与储层耦合数学模型,并采用迭代方法对其进行了求解;以此为基础,系统研究了多点注汽水平井井筒出流规律。结果表明:多点注汽水平井注汽过程中,水平段油管内压力、温度和蒸汽干度从水平井跟端到趾端逐渐降低,但压力和温度降低幅度并不显著,蒸汽干度降低幅度较为明显;蒸汽注入量与注汽阀节流压差沿水平段均呈不对称的"U"型分布,且随着时间的增加,蒸汽注入量沿水平井段的不均匀性越来越严重,蒸汽注入量不均匀系数越来越大;通过调整注汽阀沿水平井段泄流面积可以在一定程度上减缓蒸汽沿水平井筒的不均匀注入。

Based on the string structure of horizontal wells with multiple steam injection valves and in consideration of the variable mass flow of injected steam in horizontal wellbore as well as the impacts from throttle differential pressure of steam injection valve,a coupled reservoir-wellbore model of horizontal well with multiple steam injection valves were established and solved using an iterative method.On this basis,the outflow performance of horizontal wellbore with multiple steam injection valves were systematically studied.The results show that the pressure,temperature and steam quality in the tube of horizontal section gradually drop from the wellbore heel to toe in the multipoint steam injection process of horizontal wells.Moreover,the decrease of pressure and temperature is insignificant,while that of steam quality is more obvious.The steam injection rate and the throttle differential pressure of steam injection valve present the＂U＂-shaped asymmetrical distribution along the horizontal section.In addition,with the time increasing,the non-uniformity of steam injection rate along the horizontal wellbore is intensified,and the non-uniformity coefficient is becoming greater.The non-uniform injection of steam along horizontal wellbore can be slowed down to a certain extent by adjusting the drainage area of steam injection valves.