EOR - CO2 Injection: Does it really benefit the enviroment? 1

[Radionise]

CO2 injection is becoming more and more famous as an enhanced oil recovery (EOR) method. If I'm not mistaken, CO2 also dissolves in the oil, reduces its viscosity hence easing the extraction process.

But wouldn't this mean that the CO2 would come back to the surface again? And as a consequence of this:

1. Wouldn't the concentration of CO2 in the oil be effectively increased, hence requiring an addition necessity of having a CO2 removal unit on the topside?

2. Since CO2 is being brought back to the surface, what logic would this method possess in terms of global warming mitigation then? After all, even if the CO2 concentration in the oil is negligible and facilitation of a CO2 removal process is not necessary, it will still be released during combustion of the fuel.

Cheers!

 

[SJones]

It's a recycling process. Yes, a proportion of the injected CO2 will come back; but, where does the injection CO2 generally come from in the first place? So, the more CO2 coming back, the more CO2 available for reinjection (if required). It won't prevent the products of combustion but it will keep the extracted CO2 out of the atmosphere.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[ppata]

There are two different types of CO2 injection: technological and residual. The residual injection is not an EOR method (is just for environmental purposes). The technological injection (EOR) is a function of the miscibillity pressure. If the injecton is at a higher pressure you will have the effect you just describe, at a lower pressure the CO2 will remain separated (will not be dissolved).
With SJones answer and this one you have a complete image, but if you want to go further, you can read “Practical Aspects of CO2 Flooding”, By Perry Jarrell, Charles Fox, Michael Stein, Steven Webb from SPE library.


Best regards,
Andrei

 

[Radionise]

Ppata,

I browsed through the elibrary and I can't find any information on the above quoted title. I found that it is actually a short course. Do they normally put it as a reading material in the elibrary?

I'm interested to know more about the surface facility design and operation.

 

[ppata]

Radionise,

“Practical Aspects of CO2 Flooding” is a book from SPE monograph series. I have that book from:

https://www.spe.org/mbrservices/Sho...mpanyPassed=SPE&ProdCdPassed=SPE-PROD-MONO022

Surface facility design and operations you can find in chapter 5.

Best regards,
Andrei

 

[JLSeagull]

Isn/t CO2 injection used primarily to help maintain the reservoir pressurebeing brought back to the surface, and only secondarily to eliminate atmospheric venting of the produced CO2? Perhaps this contributes to mitigating greenhouse gas emissions but surely the objective is to enhance oil recovery.

 

[ppata]

Dear gents,

I'm a reservoir engineer and from professional point of view my interest in this is as an EOR method. But as a human being, I think nothing is more important than environment. The previous reply was just a technical answer to a technical question.

Best regards,
Andrei

 

[Ashereng]

CO2 injection is primarily developed as an EOR. The success at Weyburne by Encana means that more people are looking at CO2 as a viable solution to extending the life of existing and formerly thought to be tapped out fields. I am seeing new test sites in very established fields.

If it has an environmental benefit, I am sure the producers will definitely highlight it. Ultimately, if it is not useful for EOR, most procuders would not be doing it.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[SJones]

We seem to be getting a bit confused with our terminology here. I'm only a simple materials & corrosion engineer but working on a miscible gas EOR project, I understand the following: CO2 injection can be used for reservoir pressure maintenance (secondary recovery) or as a miscible agent for the hydrocarbon helping to flush it from the formation (tertiary recovery - classed as EOR Enhanced Oil Recovery)

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[DrillerNic]

Most of my (limited) experience with CO2 in jection has been on WAG (Water Alternating Gas) projects, where the CO 2 mobilises the oil and the water moves it along- ie using the miscible properties of CO2. I guess you could use it as simple pressure maintenance gas, but wouldn't it be very expensive? Especially when there's all that associated gas available?

Recently, there are a couple of projects where CO2 is being injected as sequestration or disposal (ie the BP Miller Peterhead power station thing), where the EOR aspects are a bonus, but the majority of the CO2 will stay in the reservoir.