凝析气井井筒动态分析方法及软件研制

BOREHOLE PERFORMANCE ANALYSIS AND SOFTWARE DEVELOPMENT OF CONDENSATE GAS WELLS

常规凝析气井井筒动态分析仍多沿用单相气井的节点分析进行经验修正的方法去近似分析,忽略了井筒中流体相态变化和组成变化的影响。特别对于富凝析气井,更应该考虑井筒中相态变化的影响。文章在常规方法基础上,按流态的不同综合利用垂直管流公式,根据井筒内气液比高低将凝析气井井筒动态分析分为高气液比和低气液比两种情况,结合流体相平衡热力学闪蒸计算,运用状态方程模拟,对其中的偏差因子、气液界面张力、粘度等进行修正,该预测方法就比常规方法更适用于凝析气井。同时根据文章给出的凝析气井井筒动态预测方法和计算模型,采用VB语言结合Access数据库,编制了相应的凝析气井井筒动态计算软件包,运用该软件,可以准确预测凝析气井的井筒动态,改善数值模拟一体化动态分析效果。现场应用取得了较好的效果。

The borehole performance analysis of condensate gas wells usually uses the modified method of nodal analysis for single-phase gas wells, which ignores the variation of phase behavior and composition of the borehole fluid. The effect of the variation of phase behavior should be more considered especially for the gas wells with rich condensate. Based on the conventional ways, the formula of vertical-pipe flow is applied comprehensively according to the difference of flow behaviors. The borehole performance analysis of condensate gas wells is divided into 2 cases: high gas/liquid ratio and low gas/liquid ratio according to the gas/liquid ratio in the borehole. Integrating the flash calculation of phase-balance thermodynamics and using the simulation of EOS, the compressibility factor, gas/liquid superficial tension, viscosity and so on are corrected. The method is more suitable for condensate gas wells than the conventional ways. According to the method and calculating mode given in the paper for borehole performance prediction of condensate gas wells, and using VB language with Access database, the-software package of borehole. performance calculation of condensate gas wells is developed for corresponding condensate gas wells. With the software, the borehole performance of condensate gas wells can be detected accurately, and the whole performance analysis results of numerical simulation can be improved. Good results have been achieved in the field application.