Development of New Oil Recovery Process Controlling Formation of Polymer Gel in Reservoirs

CAG （CO-D22-Water Alternating Gelant Injection Process）是一个新的方案。它由两种解决方案的替代注射组成：饱和的碳二氧化物和凝胶（聚丙烯酰胺、NaAlO-D22-D2和NaOH的组合溶液）。要设计和评估CAG实验室实验进行了性能。Polyacrylamide， NaAlO-D22-D2和NaOH in gelant were selected from beaker tests。该实验表明，使用玻璃珠包装的核心进行了实验，即CAG能够形成凝胶，并通过大约1/60到1/360的原始渗透性来减少核心渗透性。在平行展示中安装了带有线性核心的洪水实验和带有不同永久性核心的两个线性核心的不同永久性核心，因为CAG也对提高石油的回收产生了影响。用玻璃珠包装的两个尺寸模型是建造的，以调查各层之间的交叉流的影响。当存在强大的交叉流时，凝胶放置的控制被发现是困难的。一个适当的注射方案，考虑到渗透率，当CAG应用于不同渗透性层的保留层时，必须选定;对建模研究进行监管，开发了一个数字模型，以预测流动行为在色情媒体中实现凝胶形成。模型计算可以通过匹配速率常量的凝胶生成。提议的CAG是一种简单而建议的方法，用于恢复从matured reservoirs中恢复石油的简单和建议的方法。建议对注射方案进行进一步的研究以控制凝胶形成，供其实地应用使用。

CAG (COィイD22ィエD2-Water Alternating Gelant Injection Process) is proposed as a new scheme of in-situ polymer gelation in reservoirs. It is comprised of alternate injection of the two solutions : saturated aqueous carbon dioxide and gelant (aqueous solution of polyacrylamide, NaAlOィイD22ィエD2 and NaOH).To design and evaluate the CAG laboratory experiments were performed. The optimum concentrations of polyacrylamide, NaAlOィイD22ィエD2 and NaOH in gelant were selected from beaker tests. The experiments using glass-bead packed cores revealed that the CAG was able to form gel and reduce the core permeability by about 1/60 to 1/360 of its original permeability. Flood experiments with linear cores and with two linear cores of different permeabilities mounted in parallel showed that the CAG was also effective to increasing oil recovery. Two-dimensional models packed with glass beads were built to investigate the effect of crossflow between layers on the CAG. The control of gel placement was found to be difficult when strong crossflow existed. An appropriate injection scheme considering the permeability ratio must be selected when the CAG is applied to reservoirs consisting of different-permeability layers.Regarding to modeling study, a numerical model was developed for predicting flow behavior accompanying gel formation in porous media. The model calculations were able to reproduce the experimental results by matching the rate constant of gel formation.The proposed CAG is a simple and promising method to recover remaining oil from matured reservoirs. The further study on injection scheme to control gel formation is recommended for its field application.