It is widely accepted that oil recovery during waterflooding can be improved by modifying the composition of the injected brine, typically by depleting the total salinity or altering potential determining ions (PDI) such as: Ca²⁺, Mg²⁺, and SO₄²⁻ concentration. Numerous laboratory experiments and field tests have demonstrated this effect in both clastic and carbonate rock Samples and reservoirs. However, some authors have found alternative ions, such as phosphate (PO₄²⁻) and borate (B(OH)₄^-) which, in some cases, presented additional recovery and have thus opened the discussion for potential alternative ions to enhanced oil recovery. With this in mind, copper ion's potential for enhanced oil recovery (EOR) was studied, combining different conditions usually employed on smart water experiments, such as depleting the total salinity and removing the PDI to highlight the real effect of copper on additional oil recovery. The investigation was carried out with Brazilian pre-salt reservoir Samples in imbibition experiments using Amott cells at ambient pressure and 63 °C. The evaluation of the copper effect on oil recovery for coreflooding was proved in a previous paper by Bernadinelli et al. (2021), however the analysis with imbibition experiments in this study aim to clarify the effect of copper on the capillary pressure, by analyzing the eventual additional oil production. These Samples were prepared and aged, and the oil production was monitored during the experimental time. The experiments were carried in four sequences to evaluate the effect of copper on oil recovery, consisting first of salinity reduction from 0% of sodium chloride to 100% of the original amount in the seawater (SW), followed by the removal of PDI salts, the study of the production mode (secondary or tertiary), and the analysis of the copper chloride concentration on the final recovery. The results using copper at the secondary recovery showed remarkable increases (from 6.3% to 10.0%) of the original oil in place (OOIP) compared to the oil recovered from the formation water (FW). In tertiary mode, the best recoveries occurred at salinities between 8 and 18 kppm and copper chloride (1 g/L), and presented increasing recoveries 3.9%, 5.8%, and 9.3% of OOIP. This work presents an initial investigation on the use of copper as an active ion for the smart water effect and sheds light on its effect on both secondary and tertiary modes for strategies of recovery that use soaking methods and also for fractured reservoirs.

人们普遍认为，可以通过改变注入盐水的组成来提高注水期间的采油率，通常是通过降低总盐度或改变电位决定离子 (PDI)，例如：Ca ²⁺、Mg ²⁺和 SO ₄ ^{2 -}浓度。许多实验室实验和现场测试已经在碎屑和碳酸盐岩样品和储层中证明了这种效果。然而，一些作者发现了替代离子，例如磷酸盐 (PO ₄ ^2- ) 和硼酸盐 (B(OH) ₄ ^-)，在某些情况下，它提供了额外的采收率，因此开启了关于提高石油采收率的潜在替代离子的讨论。考虑到这一点，研究了铜离子提高石油采收率 (EOR) 的潜力，结合了智能水实验中通常采用的不同条件，例如耗尽总盐度和去除 PDI，以突出铜对额外石油采收率的实际影响。该研究是在巴西盐下储层样品的吸胀实验中使用 Amott 池在环境压力和 63°C 下进行的。Bernadinelli 等人在之前的一篇论文中证明了铜对岩心驱采油效果的评价。(2021)，然而，本研究中的自吸实验分析旨在阐明铜对毛细管压力的影响，通过分析最终的额外石油产量。制备和老化这些样品，并在实验期间监测产油量。实验分四个顺序进行，以评估铜对石油采收率的影响，首先包括将海水 (SW) 中的盐度从 0% 的氯化钠降低到 100% 的原始量，然后去除 PDI 盐，生产模式（二级或三级）的研究，以及氯化铜浓度对最终回收率的分析。在二次采收中使用铜的结果表明，与从地层水中采收的油 (FW) 相比，原始地层油 (OOIP) 显着增加（从 6.3% 到 10.0%）。在三级模式下，最佳回收率发生在 8 至 18 kppm 盐度和氯化铜 (1 g/L) 之间，并呈现 OOIP 的 3.9%、5.8% 和 9.3% 的回收率增加。这项工作对使用铜作为活性离子来实现智能水效应进行了初步研究，并阐明了铜对使用浸泡法的采收策略以及裂缝油藏的二次和三次模式的影响。