注汽管柱管鞋下入深度对注汽动态的影响

Effects of injection pipe shoe setting depth on steam injection performance

针对蒸汽吞吐注汽管鞋放置在完井段顶部(模式A)和底部(模式B)两种模式,通过分析完井段水蒸气的变质量流特征建立了能量守恒方程,考虑随注入时间延长油层加热范围扩大对径向导热造成的影响,对时间函数进行了修正。以胜利油区单家寺油藏参数为基础,研究完井段蒸汽参数的变化特征。结果表明,管鞋模式A条件下,蒸汽流经完井段截面积突然增大以及变质量流动,会使汽液分离作用增大,重力效应增强,完井段的蒸汽参数变化比井筒的大;管鞋模式A完井段压力和蒸汽干度变化幅度比管鞋模式B的大,两种管鞋模式蒸汽干度变化方向相反,实际生产过程中,可以根据吞吐周期轮回改变管鞋下入深度,以改变完井段吸汽剖面;随完井段长度增加,射孔段顶底的蒸汽压差和干度差增大,注汽速度的选择应充分考虑注汽设备工作条件、油层破裂压力和油层的吸汽能力。

Two different shoe setting modes of locating at the top（A） and at the bottom（B） of well completion intervals for steam injection pipe were introduced. Energy conservation relationship in well completion intervals was developed by analyzing variable mass flow characteristic of the steam. Time function was modified considering the influence of reservoir heating area enlarging with the injecting time prolonging on radial heat conduction. The steam injection performances were calculated on the basis of the reservoir parameters of Shanjlasi reservoir in Shengli Oilfield. The results show that the steam parameters variation in well completion intervals is larger than that of wellbere because the cross-section area increases suddenly when steam flows through well completion intervals and the flow of steam is variable mass flow, and the separation effect and gravity effect of steam and liquid increase for mode A. The pressure and steam quality difference along well completion intervals for mode A are larger than those of mode B, and the variation trends of steam quality for two modes are opposite. Different injection pipe shoe setting depth can be changed periodically to improve steam injection profile of well completion intervals for steam soaking well. The difference of pressure and steam quality between top and bottom of the completion interval increase with the interval length increasing. The steam injection rate should be selected considering the steam generator, formation fracture and deliverability.