多孔介质中凝析气衰竭及注水开发机理研究

【作者】 汪周华；

【导师】 郭平；

【作者基本信息】 西南石油学院 ， 油气田开发工程， 2004， 硕士

【摘要】 凝析气田已在我国气田开发中占有重要的位置，其开发已受到石油工业界的重视。凝析气田是一类极为特殊而复杂的气田；一方面由于能同时采出天然气和凝析油而具有重要的经济价值；另一方面，在开发过程中由于地层压力的降低会出现反凝析的现象，从而使凝析气藏开发变的更为复杂，如何提高凝析油采收率变的更难。 凝析气藏通常采用衰竭或循环注气的开发方式，虽然采用衰竭开发方式大量的液态烃由于反凝析而损失在地层中，但是由于投资费用低，该方式在我国仍然是主要开发方式。本文结合塔里木、中原以及大港岩心衰竭实验，对凝析气藏衰竭开发机理以及影响凝析气藏衰竭开发效果的因素进行了深入分析；采用实验方法测试了凝析气衰竭临界流动饱和度、凝析油气采收率及在多孔介质中平衡凝析油气相渗曲线；结果发现真实相渗与常规相渗差别很大，分析认为导致其差异主要是由于界面张力的影响。采用两种类型相渗曲线用CMG数值模拟软件对实验结果进行模拟和预测。研究表明，岩心衰竭实验比PVT筒中凝析油采收率高；采用新的相渗曲线对凝析油衰竭采收率预测结果更能代表实际长岩心中衰竭实验结果。 国内首次开展注水开发凝析气藏室内研究，分别从水驱机理、实验对其可行性进行了探讨。实验研究结合板桥中区板Ⅱ组废弃凝析气藏，对气藏流体进行了PVT分析以及不同的注水压力、注水速度的长岩心驱替实验。研究表明注水速度、注水压力、注水量不同，凝析气藏的采收率不同；废弃凝析气藏注水开发比衰竭式开发可以获得更高的凝析油、气采收率。更多还原

【Abstract】 Gas condensate fields are parts and parcels in the development of the gas field in China, the development of the gas condensate fields are lay store by the petroleum industry. Gas condensate fields are kinds of exceptive and complicated gas field; they assume key economic value because they both produce natural gas and condensate oil; the appearance of retrograde condensation because of the declining of the formation pressure during the development of those fields can make the development of this fields difficult, and because of it ,it is difficulty to improve the percent recovery of condensate oil.The conventional development fashions for the gas condensate fields are natural depletion and cyclic gas injection. Although a good deal of condensate oil is loss in the formation because of the appearance of retrograde condensation by the method of natural depletion, it is the main development method in China because of the lower investment cost. This paper closely researches the natural depletion mechanism for gas condensate fields and the factors affecting the effictiveness of developing the gas condensate fields by natural depletion with the help of the core experiments of Talimu ZhongYuan and DaGang; tests the critical flow saturation of condensate oil during the period of the depletion, the percent recovery of condensate oil and gas, the real relative permeability curves of equilibrium condensate oil and gas in porous medium . The results show that the real relative permeability curves are more different than the conventional ones, this paper thinks the IFT is the main reason leading the difference ; with two types of relative permeability curves, simulates and forecasts the results of experiments by CMG.. The research shows that the percent recovery of natural gas and condensate oil in core experiments are larger than one in PVT experiments; the forecasted percent recovery of condensate oil in depletion with the new relative permeability curves is more close to the result of depletion experiments in the real cores.This paper first conducts indoor waterflooding gas condensate system experiments in China, approaches the feasibility of waterflooding gas condensate from the aspects of the mechanism, experiment . The cores and the fluids in experiments are from the BanQiao abandoned gas condensate reservoirs. This paper conducts PVT analysis on the fluids and conducts different pressure and speeds waterflooding experiments. The research shows that different pressure, speeds and quantity of water injection can lead to different percent recover}’; water injection in abandoned gas condensate reservoirs can yield higher the percent recovery of natural gas and condensate oil than those in the natural depletion.更多还原