Abstract

Controlling unwanted water has been major objective of oil and gas producers. Our theoretical and experimental studies demonstrated that treatment with a preformed particle gel (PPG) of poly(AAm-co-AA) is a successful approach to control unwanted water in oil fields. The swelling capacity of the gels in salt water (formation water) is one of the most crucial criteria in the selection of hydrogel types. In this study an efficient series of gels of acrylamide and acrylic acid, as P(AAm/AA) copolymers, were synthesized by a free radical method. A central-composite Design of Experiments (DOE) approach was employed to design the experiments and to optimize the desired properties of the copolymers. The mole ratio of AAm/AA, mole percentage of the crosslinker agent (N,N'-methylenebisacrylamide, MBA) and swelling time were simultaneously examined as key factors affecting the swelling behavior of the hydrogels. The results showed that these three factors were the dominate factors and were useful for prediction of the swelling process. The predicting model indicated that the optimized ranges of AAm/AA ratio, MBA mole percentage and swelling time, causing the maximum swelling percentage of PPG samples, were 6.77 to 8.54, 9.92 to 11.6% and 170.7 to 179.99 min, respectively. The maximum swelling percentage of the PPG samples was found to be 390% in the optimum ranges of AAm/AA, MBA mole percentage and swelling time. Additionally, it was evident from the results that the predicted results were in good agreement with the experimental data.

摘要

控制不需要的水一直是石油和天然气生产商的主要目标。我们的理论和实验研究表明，用聚 (AAm-co-AA) 的预制颗粒凝胶 (PPG) 进行处理是控制油田中不需要的水的成功方法。凝胶在盐水（地层水）中的溶胀能力是选择水凝胶类型的最关键标准之一。在这项研究中，通过自由基方法合成了一系列有效的丙烯酰胺和丙烯酸凝胶，作为 P(AAm/AA) 共聚物。采用中心复合实验设计 (DOE) 方法来设计实验并优化共聚物的所需性能。AAm/AA的摩尔比，交联剂的摩尔百分比（N,N'-亚甲基双丙烯酰胺 (MBA) 和溶胀时间同时被视为影响水凝胶溶胀行为的关键因素。结果表明，这三个因素是主导因素，可用于预测溶胀过程。预测模型表明，导致PPG样品溶胀百分比最大的AAm/AA比、MBA摩尔百分比和溶胀时间的优化范围分别为6.77~8.54、9.92~11.6%和170.7~179.99 min。发现在 AAm/AA、MBA 摩尔百分比和溶胀时间的最佳范围内，PPG 样品的最大溶胀百分比为 390%。此外，从结果中可以明显看出，预测结果与实验数据非常吻合。