Immiscible CO2 Flood

Can a CO2 flood be run at low pressure? If so, how will successful will it be?

One operator proposed modifications to an immiscible CO2 flood. In his application, he reported on the progress of the flood and claimed additional recovery by several means even without miscibility.

Understanding the intelligence contained in this application is important to anyone wanting to try a gas flood.

You can see his application documents in moments by clicking on the button below labelled 'Buy these application documents now.'

Experimental status over

With the approval of this application, the earlier experimental status was removed. This allows you to review the application and then check out the performance in Accumap.

All applications are ground truthed to real UWIs. You won't find that in SPE papers.

And you won't find SPE papers that deal with CO2 flooding below minimum miscibility pressure.

Below minimum miscibility pressure

In EOR courses, you'll be taught that CO2 mixes with oil only above a certain pressure. This minimum miscibility pressure (MMP) is almost always much higher than virgin pressure.

Some operators boost the pool pressure to the MMP. But increasing the pool pressure to 20-30% above original pressure is costly and presents some operational risks.

These days, many more operators are injecting at below MMP because it's easier. The application that's subject of this blog post was very scientific in its study of injection below MMP. And they believed incremental oil reserves were about 10%.

Oil swelling

The operator believed that incremental oil recovery was a result of oil interactions with the reservoir fluids causing oil swelling, decreased interfacial tension, and reduced oil viscosity.

Traditional CO2 floods count on miscibility reservoir fluids. The resultant mixture is lighter and thinner allowing better drainage.

Gas lift

This flood, like many other gas floods get some of their cost advantage from auto-lift and unique type of gas lift. In auto-lift, gas from gas cap is perforated in each wellbore and allowed to lift the liquid column in a tightly controlled manner.

This type of lift is very inexpensive to set up and maintain. A reduction of lifting costs further adds to the economic viability of gas floods.

Tags: Gas Injection, Flood

Granger Low   15 Feb 2017

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