基于指数伤害模型的砂岩酸化模拟

在两酸三矿物模型及精细化模型基础上建立了符合地层尺度的砂岩基质酸化径向非均质流动反应数学模型。为了研究伤害带孔、渗分布差异对酸化模拟效果的影响,将伤害带渗透率合理地假设为指数型分布。通过将伤害带孔、渗分布常规模型与指数模型分别引入径向非均质流动反应模型中,重点讨论了不同伤害带假设对酸化模拟效果的影响。模拟发现,前者酸化后地层孔隙度沿径向呈递减规律;而后者酸化后地层孔隙度沿径向呈递增规律,径向上孔隙度起伏更为平缓,说明伤害带内渗流条件得到了均匀改善,其结果更符合真实情况。在相同注入条件下,指数模型较常规模型计算的酸化效果更显著,同时大排量有利于增加酸液深穿透距离,但与小排量相比,其酸化后的油井增产倍比相当。

Sandstone acidizing simulation based on exponential damage model

A mathematical model of sandstone matrix acidizing radial heterogeneous flow reaction which conforms to reservoir scale, is developed based on Heterogeneous Sandstone Reservoir Generalized Distribution Model and Fine Scale Sandstone Acidizing Model. In order to study the effect of pore and permeability distribution differences of damage zone on acidification simulation, the permeability of damage zone was assumed as exponential distribution. By introducing the model of pore and permeability distribution differences of damage zone and exponential model into radial heterogeneous flow mathematical model respectively, we focused on the influence of different damage zone assumption on acidizing simulation effect. Simulation results show that in the former case the formation porosity along the radial direction is diminishing after acidizing, while in latter case the formation porosity along the radial direction is still increasing after acidizing and porosity undulates more gently along radial direction, indicating that seepage conditions is improved evenly in the damage zone and the result conforms to the real situation. Under the same condition of injection, acidification effect of exponential model calculation is more significant. Compared with the small injection rate, the large one is helpful to increase acid penetration distance, but both of the stimulation ratios are almost same.