德克萨斯大学奥斯汀分校(UT)的研究人员提出的一种新的提高石油采收率(EOR)方法在建模研究中显示出良好的结果——比传统的提高石油采收率方法生产更多的石油、储存更多的碳，而且更安全。

这三重效益源于德克萨斯大学正在领导的替代碳载体技术研究。
 
替代碳载体是专门设计用于在地下地层中储存大量碳分子的化合物。当这些化合物由二氧化碳(CO₂ ₎合成时，它有助于优化这种温室气体的运输、使用和储存。

在一项将该技术应用于 EOR 场景的研究中，德克萨斯大学杰克逊分校地球科学学院和科克雷尔工程学院的研究人员发现，与传统的 EOR 方法相比，新的碳载体方法可多回收 19.5% 的石油，并多储存 17.5% 的碳。

“这项技术背后的想法是最大限度地提高石油采收率，同时增加碳储存的数量和安全性，”该研究的主要作者、杰克逊学院经济地质局研究助理教授阿布扎尔·米尔扎伊-帕亚曼 (Abouzar Mirzaei-Paiaman) 说。

研究结果发表在美国化学学会期刊《能源与燃料》上。

几十年来，石油和天然气公司一直在利用提高石油采收率 (EOR) 技术从油藏中榨取更多石油。基于二氧化碳的 EOR技术利用_二氧化碳气体从岩石孔隙中驱出残余石油，并将二氧化碳封存_在地下。

借助碳捕获与封存技术，企业可以利用碳氢化合物燃烧产生的二氧化碳_排放来开采更多石油——这有助于减少石油的净碳足迹，因为部分排放物不会进入大气。然而，为了最大限度地提高储层空间的碳排放量，最好将二氧化碳作为合成更有效碳载体的起点，该_研究的共同作者、科克雷尔学院希尔德布兰德石油与地球系统工程系的教授 Ryosuke Okuno 表示。

“我们其实不必使用二氧化碳_；我们可以找到更好的方法，”他说，“我们的想法是捕获二氧化碳_，并将其转化_为甲酸盐，例如甲酸钠或甲酸钾。”

甲酸盐是一种碳基分子，可以由二氧化碳气体合成_。奥野表示，在相同条件下，甲酸盐_比同等数量的二氧化碳更容易储存在岩石孔隙中。

此外，甲酸盐化合物的水基溶液也比二氧化碳更粘稠_，这有助于提高剩余油的采收率和地层中碳的封存效率。

研究人员测试的EOR方法是交替使用二氧化碳气体段塞驱_油，以及水基甲酸盐溶液段塞，以帮助将油输送至生产井。研究人员将该方法与两种传统的EOR方法进行了比较：一种是仅使用二氧化碳_气体，另一种是交替使用二氧化碳气体和水。

所有三种 EOR 方法都在一个模拟油藏中进行了测试，该模拟油藏是使用来自西德克萨斯州二叠纪盆地真实油田的数据创建的。

研究人员发现，新型碳载体方法与单独注入二氧化碳相比，原油采收率提高了19.5% _{，与二氧化碳}和水联合注入相比，采收率提高了1.9% 。对于碳封存，碳载体方法与单独注入_二氧化碳相比，碳封存率提高了2.5% ，与_二氧化碳和水联合注入相比，碳封存率提高了17.9% 。

除了石油采收和碳封存外，研究人员还分析了碳在储层中的封存安全性。他们发现，甲酸盐-二氧化碳_交替注入是最安全的方案，因为它最大限度地减少了可能从储层中逸出的自由流动二氧化碳的量_。此外，它还创造了一个化学缓冲环境，可以更好地保护储层岩石的完整性。

总体而言，这项研究表明，使用碳载体进行EOR（提高石油采收率）的效果良好。然而，奥野表示，要使其在工业上进一步精炼和发展，还需要采取更多措施。首先，目前利用二氧化碳生产的甲酸盐_数量还不足以维持EOR生产。

Mirzaei-Paiaman 研究了针对碳载体技术的潜在碳储存财政激励措施。他表示，调整政策以最大化碳储存效益，有助于激发碳载体市场。

他说：“只要政策和法规支持某项技术，公司就会朝着这个方向发展。”

这项研究由德克萨斯州先进资源回收计划资助，该计划隶属于经济地质局，旨在最大限度地提高德克萨斯州地球资源的产量和盈利能力，同时鼓励负责任的经济发展，支持教育和环境管理。地下能源与环境中心的Energi模拟工业附属项目（碳利用与封存）也为这项研究提供了支持。

A new method for enhanced oil recovery (EOR) proposed by researchers at The University of Texas at Austin (UT) is showing promising results in modeling studies — producing more oil, storing more carbon, and doing so more safely than conventional enhanced oil recovery methods.

This trifecta of benefits stems from alternative carbon carrier technology research being led at UT.
 
Alternative carbon carriers are chemical compounds specifically engineered to store larger quantities of carbon molecules in subsurface formations. When these compounds are synthesized from carbon dioxide (CO₂), it can help optimize the transportation, use, and storage of this greenhouse gas.

In a study that applied the technology to EOR scenarios, researchers at the UT Jackson School of Geosciences and the Cockrell School of Engineering found that the new carbon carrier method recovered up to 19.5% more oil and stored up to 17.5% more carbon than conventional EOR methods.

“The idea behind this technique is to maximize oil recovery while also increasing the amount and security of carbon storage,” said the study’s lead author, Abouzar Mirzaei-Paiaman, a research assistant professor at the Jackson School’s Bureau of Economic Geology.

The results were published in Energy & Fuels, a journal of the American Chemical Society.

Oil and gas companies have been using EOR to squeeze more oil out of reservoirs for decades. CO2-based EOR works by using CO₂ gas to dislodge the residual oil from pores in the rock and traps the CO₂ underground in the process.

With carbon capture and storage technology, it’s possible for companies to use CO₂ emissions produced by burning hydrocarbons to recover more oil — which helps reduce the net carbon footprint of the oil by keeping some of the emissions out of the atmosphere. When it comes to maximizing the amount of carbon emissions stored in a reservoir space, however, it’s better to treat CO₂ as a starting point for synthesizing more effective carbon carriers, said study co-author Ryosuke Okuno, a professor in the Cockrell School’s Hildebrand Department of Petroleum and Geosystems Engineering.

“We don’t really have to use the CO₂; we can find a better way,” he said. “Our idea was to capture the CO₂ and to convert the CO₂ into a formate species like sodium formate or potassium formate.”

Formate is a carbon-based molecule that can be synthesized from CO₂ gas. It’s more readily stored in the rock pores than a comparable quantity of CO₂ gas in the same conditions, according to Okuno.

Moreover, water-based solutions of formate compounds are also more viscous than CO₂, which helps improve efficiency in recovering remaining oil and storing carbon in the formation.

The EOR method tested by the researchers involved alternating slugs of CO₂ gas to dislodge the oil with slugs of the water-based formate solution to help sweep the oil toward a production well. The researchers tested their method against two conventional EOR methods: One using CO₂ gas alone, the other alternating slugs of CO2 gas and water.

All three EOR methods were tested in a simulated reservoir that was created using data from real oil fields in the Permian Basin in West Texas.

The researchers found that the new carbon carrier method increased oil recovery by 19.5% compared with exclusive CO₂ injection and by 1.9% compared with combined CO₂ and water injection. For carbon storage, the carbon carrier method increased carbon storage by 2.5% compared with exclusive CO₂ injection and 17.9% compared with combined CO₂ and water injection.

In addition to oil recovery and carbon storage, the researchers also analyzed how securely the carbon was stored in the reservoir. They found that the formate-alternating-CO₂ injection was the most secure option because it minimized the amounts of free-flowing CO₂ — which can potentially escape from the reservoir. It also created a chemically buffered environment that could better preserve the integrity of the reservoir rock.

Across the board, the study shows promising results for EOR with carbon carriers. However, making it a reality for industry to refine and develop further will require more steps, Okuno said. For one, formate is not yet being produced from CO₂ at the quantities needed to sustain EOR production.

Mirzaei-Paiaman has studied potential financial carbon storage incentives for carbon carrier technologies. He said that aligning policy so that it maximizes carbon storage benefits could help spark a market for carbon carriers.

“Whenever policy and regulations support a technology, companies move toward that direction,” he said.

The research was funded by the State of Texas Advanced Resource Recovery program, a research program at the Bureau of Economic Geology focused on maximizing the production and profitability of earth resources in Texas while encouraging responsible economic development, supporting education and environmental stewardship. The Energi Simulation Industrial Affiliate Program on Carbon Utilization and Storage in the Center for Subsurface Energy and the Environment also supported the research.