同心管分层注气井筒温度场计算方法

Method for Calculating Temperature Field in Stratified Gas Injection Wells with Concentric Dual Tubes

凝析气藏注气井井筒温度场计算是循环注气工艺设计及参数优化的重要基础。根据能量守恒原理和井筒传热机理,建立了同心双管分层注气井筒温度分布计算模型,并对井口注入参数和内外油管尺寸进行了敏感性分析。结果表明,外油管直径和内外管环空注气量是影响井筒温度分布的主要因素,注气温度仅对井筒上部的温度分布有明显影响。当外油管直径一定时,内油管直径大小对井筒温度影响较小;当内油管注气量不变时,内外管环空注气量越大,井筒流温梯度则越小,井底温度也越低。

The calculation of wellbore temperature field for gas injection wells in condensate gas reservoir was an important foundation for technological design and parameter optimization of cyclic gas injection.On the basis of the principle of conservation of energy and the wellbore heat transfer mechanism,a calculation model of temperature distribution for injection wells with concentric dual tubes was established and a sensitivity analysis was made on wellhead injection parameters and inner/outer tube sizes.Results show that outer tube diameter and gas injection volume in annulus are the main factors influencing the wellbore temperature distribution,and the injection temperature has obvious influence on the upper wellbore only.If the diameter of the outer tube keeps constant,the inner tube size has a less influence on the temperature of the wellbore.Meanwhile,if the injection volume of the inner tube keeps constant,the bigger the injection volume in annulus is,the smaller the flowing temperature gradient in wellbore is and the lower the bottom hole temperature would be.