Investigating the Propagation of the Colloidal Dispersion Gel (CDG) in Thick Heterogeneous Reservoirs Using Numerical Simulation

在过去几十年中，关于胶体分散凝胶（CDG）是否比聚合物驱更能提高扫油效率一直存在争议。本研究使用CMG-STARS模拟器构建了一个数值模型，研究了将0.1 PV的CDG注入一个倒九点法的四分之一区域的行为。该模型代表了一个由于高异质性和不利的流度比导致高含水率的厚层异质油藏。研究中实施了来自已发布文献的不同实验结果，以研究这些参数对CDG传播的影响。结果证实，CDG能够深入传播到高渗透层中，并比聚合物溶液更有效地降低其渗透率。此外，CDG的剪切变稀行为有助于其仅选择性地渗透到高渗透条带中，从而减少了通过机械方法隔离高渗透层的成本。结果还显示，润湿性对处理效果有巨大影响，水润系统比油润系统获得了更高的结果，并且对低渗透层的损害较小。研究还发现，当考虑CDG的不可逆吸附时，对后处理水的性能可能会被高估。然而，即使在可逆吸附的情况下，长时间注入后处理水也无法完全消除由CDG驱引起的渗透率降低。结果揭示了CDG降解程度越高，回收因子越低。研究还显示了考虑聚合物和CDG联合注入的重要性。此外，随着储层盐水和/或配制水的盐度增加，回收因子降低，而随着聚合物/交联剂比增加，回收因子降低，随着聚合物水解度增加，回收因子和残余阻力因子增加。

CMG软件的应用情况

在本文中，使用了CMG-STARS模拟器来构建和运行数值模型。该模型用于研究CDG在厚层异质油藏中的传播行为，特别是其在高渗透层中的传播和渗透率降低效果。模型考虑了多种因素，包括凝胶的形成、凝胶化时间、反应速率、凝胶动力学模型、阻力因子和残余阻力因子等。通过模拟，研究人员能够详细分析CDG的传播深度、选择性渗透能力以及在不同条件下的性能表现。CMG-STARS模拟器的使用为研究提供了强大的工具，使得研究人员能够深入理解CDG在复杂油藏条件下的行为，并为现场应用提供了理论支持。

中文作者单位

Tariq Khamees 和 Ralph Flori 美国密苏里科技大学地质、地球物理与石油工程系

Abstract: Over the last few decades, there has been a dispute regarding the ability of colloidal dispersion gels (CDG) to improve sweep efficiency more than polymer flooding. In this study, a numerical model was built using the CMG-STARS simulator to investigate the behavior of injecting 0.1 PV of CDG slug into one quarter of inverted nine-spot pattern. This slug was composed of 0.1 wt. % HPAM polymer solution with a polymer-to-crosslinker ratio (P/X) of 50/1. The model was represented by a thick heterogeneous reservoir with high water cut caused by high heterogeneity and adverse mobility ratio.

Different experimental results from published literatures have been implemented in the numerical model to study the effect of these parameters on the propagation of the CDG. The results confirmed that CDG could propagate deep into the thief zones and reduce their permeability more than polymer solution. Moreover, the results showed that the shear-thinning behavior of CDG could assist the selective penetration into the high-permeability streaks only, thus reducing the cost of isolating the thief zones by mechanical methods. In addition, the results showed that the wettability had tremendous effects on the treatment. Therefore, the water-wet system yielded higher results with less damage to the low-permeability layers compared to the oil-wet system. The results showed an overestimation of the performance of post-treatment water when considering irreversible adsorption of CDG. However, the prolonged injection of post-treatment water would not remove the permeability reduction caused by CDG flooding, even with reversible adsorption. The results revealed that the higher the degradation of the CDG, the lower the recovery factor. The results showed the importance of considering a combination injection of polymer and CDG. The results also revealed that the higher the salinity of the reservoir brine and/or the makeup water, the lower the recovery factor. In addition, as the polymer/crosslinker ratio increases, the recovery factor decreases, while as the polymer hydrolysis increases, the recovery factor and residual resistance factor increases.

Keywords: Colloidal Dispersion Gel, Heterogeneous Reservoirs, Numerical Simulation, In-Depth Treatment

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