Enhanced recovery

EOR Operations-2021

Our industry has been the custodian of subterranean reservoirs. We are the experts in managing and developing them. Why not use that expertise to find solutions for climate change by capturing and removing carbon and being part of the solution?

EOR Operations Introduction with abstract waves

A long time ago, my mentor, Farooq Ali, wrote a thought-provoking paper on the unfulfilled promises of enhanced oil recovery (EOR). His essential summary: EOR had not lived up to its hype and full potential. There were more than a hundred methods and techniques proposed, but only a few had succeeded commercially. Fast-forward a few decades and into the new century, and the message and conclusions have not changed.

EOR has definitely not lived up to its promise, especially from the big-picture perspective of daily oil production rates. Before the COVID-19 pandemic, the world was producing close to 100 million BOPD. Of this, only approximately 4 million BOPD was coming from EOR, and the bulk of this was from thermal. The numbers pale even when compared with shale oil, which has dominated US oil production during the past decade.

So why has EOR failed so spectacularly? The answer is complex—mostly economic, less technical. It is difficult to compete against water (flooding), where the cost of the injectant is practically free. Compare this with EOR, where you have to inject something other than water—either heat, a gas or solvent, polymer, surfactant, or something exotic such as microbes. These techniques cost money and make EOR inherently expensive. They have become the Achilles’ heel of EOR.

So, what is the message for those of us working in EOR? Make EOR cost-competitive, improve waterflooding, or join the sustainability bandwagon that is sweeping the world? That is the call of the hour, and for decades to come.

While other EOR methods such as thermal and chemical will have a limited future, injection of carbon dioxide (CO2) for EOR will be a win/win proposition. It provides a way to sequester CO2 and produce additional oil at the same time. The oil revenues provide the “U” in “CCUS” (carbon capture, utilization, and storage) that will play a vital role in the removal of CO2. CCUS is considered by most to be an essential part of the climate-change portfolio of solutions.

The papers in this feature are examples of CO2 sequestration either with EOR or in saline aquifers. One provides the EOR and storage potential in the Norwegian continental shelf. Another is a case study of improving asset performance in marginal pay regions. The third is an example that capitalizes on the US government’s 45Q tax credits for incentivizing CO2 injection.

Our industry has been the custodian of subterranean reservoirs. We are the experts in managing and developing them. Why not use that expertise to find solutions for climate change by capturing and removing carbon and being part of the solution?

This Month’s Technical Papers

Modeling Evaluates CO2 EOR,Storage Potential in Depleted Reservoirs

Advances in Midland Basin Expand Boundaries of CO2 EOR in Marginal Pay Areas

Joint Optimization of Well Completions and Controls for CO2 Use and Storage

Recommended Additional Reading

SPE 200363 Economic Assessment of Strategies for CO2 EOR and Storage in Brownfield Residual Oil Zones: A Case Study From the Seminole San Andres Unit by Bo Ren, The University of Texas at Austin, et al.

OTC 30157 Effects of CO2/Rock/Formation Brine Parameters on CO2 Injectivity for Sequestration by Muhammad Aslam Md Yusof, Universiti Teknologi Petronas, et al.

SPE 202276 Is Chemical EOR Finally Coming of Age? by Eric Delamaide, IFP Technologies


Sunil Kokal, SPE, is a principal scientist and a focus area champion of enhanced oil recovery on the Reservoir Engineering Technology team of the Exploration and Petroleum Engineering Center—Advanced Research Center at Saudi Aramco in Dhahran, Saudi Arabia. During the past 4 decades, he has been involved in applied-research projects on sustainability, enhanced/improved oil recovery, reservoir fluids, hydrocarbon phase behavior, crude oil emulsions, and production-related challenges. Kokal has spearheaded the implementation of the first CCUS and CO2-EOR demonstration project that has received many firsts and eight international awards. He is also working on an initiative on energy sustainability and circular carbon economy, a framework for reducing CO2 emissions from oil and gas. Kokal has written more than 150 technical papers and has authored two chapters for the SPE Petroleum Engineering Handbook. He has served as associate editor for the Journal of Petroleum Science and Engineering and the SPE Reservoir Evaluation & Engineering peer-reviewed journal. Kokal is a fellow of the Energy Institute, an Honorary Member of SPE, and the recipient of the prestigious 2018 IOR Pioneer award and several other international awards. He also served as an SPE Distinguished Lecturer during 2007–2008. Kokal holds a PhD degree in chemical engineering from the University of Calgary and a BS degree in chemical engineering from the Indian Institute of Technology, New Delhi. He can be reached at sunil.kokal@gmail.com.