Onboarding: What is EOR and how is it done?



Jul 07, 2023


A fresh graduate is looking for information on Enhanced Oil Recovery. Let's try a starter prompt.

How does enhanced oil recovery (EOR) work, and what are the different types?


EnerGPT gives us a great overview, with six different methods of EOR! Followup questions would help the newbie refine and explore further. Remember - the more information you give, the better the information you get back.

Enhanced oil recovery (EOR) is the process of increasing the amount of oil that can be extracted from an oil reservoir. There are different types of EOR methods, including:

1. Thermal EOR: In thermal EOR, heat is applied to the reservoir to reduce the viscosity of the oil and make it easier to produce. This can be done through steam injection (steam flooding), in-situ combustion (burning of oil in place), or the use of heated fluids.

2. Chemical EOR: Chemicals are injected into the reservoir to alter the properties of the oil, rock, or fluids. This can include the use of polymers to increase the viscosity of injected water, surfactants to reduce interfacial tension and improve oil displacement, or alkali agents to reduce acidity and improve oil recovery.

3. Gas EOR: Different gases, such as natural gas or carbon dioxide, can be injected into the reservoir to increase pressure and displace the oil. This can be done through processes like gas miscible flooding, gas displacement, or gas injection into fracturing formations.

4. Miscible EOR: In miscible EOR, gases or liquids that are miscible (capable of mixing uniformly) with oil are injected into the reservoir to mix with the oil and improve displacement. This can include the use of carbon dioxide (CO2) or hydrocarbon solvents.

5. Microbial EOR: Microorganisms or biodegradable chemicals are introduced into the reservoir to alter the properties of oil and improve recovery. These microbes can enhance oil recovery by various mechanisms, such as biosurfactant production, gas generation, or altering rock properties.

6. Electrical EOR: Electrical methods involve the application of electric currents or fields in the reservoir to improve oil recovery. This can include techniques like electrokinetics or electrothermal processes.

These different EOR methods may be used individually or in combination, depending on the specific characteristics of the reservoir and the desired outcome. They aim to overcome the limitations of primary and secondary recovery methods and increase the ultimate recovery factor of oil reservoirs.


Remember - this didn't require Google or reaching for a book. Our new user being onboarded can drill down into any of those sections by just asking the bot more questions.

Let's try a quick followup question - Electrical and Thermal EOR seem similar, why choose one over the other?

Why would I use electrical EOR over thermal EOR?

EnerGPT gives us a quick article to read in reply:

The advantages or benefits of using electrical enhanced oil recovery (EOR) methods compared to thermal EOR methods for increasing the oil recovery factor in an oil reservoir include:

1. Targeted heating: Electrical heating allows for targeting a specific area of the reservoir instead of heating the entire bulk reservoir. This allows for more effective heating of that specific area and can lead to lower heat losses. This targeted approach makes electrical methods more efficient and cost-effective compared to conventional thermal EOR methods.

2. Applicability in heterogeneous reservoirs: Electrical methods can be applied in heterogeneous reservoir environments, where the geology or characterization may vary. This means that electrical EOR techniques can be utilized in different reservoirs with different formation depths, porosity, permeability, temperature, pressure, and thickness, without being limited by these variations.

3. Faster operations: Electrical EOR methods typically have significantly faster operations compared to thermal EOR methods such as steam-assisted gravity drainage (SAGD). EEOR operates during hydrocarbon production, which avoids a differential in reservoir and wellbore pressure, thus minimizing the risk of formation damage.

Overall, electrical enhanced oil recovery methods offer the advantages of targeted heating, applicability in heterogeneous reservoirs, and faster operations compared to thermal EOR methods, making them an attractive option for increasing the oil recovery factor in an oil reservoir.


Compare and contrasts like this are a great way to learn about the advantages of an approach when you're building a plan for the field. Even the greenest engineers can use EnerGPT to help refine their plan for tricky situations - like choosing the right EOR method for the field!