稠油油藏溶剂辅助蒸汽驱前缘预测模型

为了描述注溶剂条件下蒸汽前缘的形状,首先提出蒸汽前缘气相内组分平衡状态计算方法,获得边界温度特征;其次列出前缘液相组分组成的计算过程,建立考虑三相平衡状态的蒸汽前缘形状预测模型;最后采用迭代法获得界面关键参数,并求解整个模型。结果表明:溶剂辅助蒸汽前缘形状以楔形为主,并且在较低注汽速度情况下,重质溶剂改善垂向波及系数效果明显优于轻质溶剂,对于较高注汽速度,轻质溶剂改善重力超覆现象的潜力明显大于重质溶剂。

A mathematical model for steam frontier prediction in solvent enhanced steam flooding process

In order to delineate the shape of the steam frontier during solvent enhanced steam flooding process, a computing method for two-component equilibrium was firstly proposed to acquire the temperature distribution of the water-steam interface, and then a whole composition model of the liquid phase was established to determine solvent enhanced steam flooding frontier. An iteration method was used to solve the model and the critical parameters of the interface can be calculated. The results of a case study for a specific heavy oil reservoir show that the steam frontier of the solvent enhanced steam flooding process is mainly of a wedge-shape, and heavier solvents perform better than lighter ones in terms of improving vertical sweep efficiency when the steam injecting rate is low, while the lighter solvents have a better capability to overcome the gravity induced steam override problem than the heavier ones when the injecting rate is very high.