adv of Capillary pressures.

[ELgharib]

Hi,

Please can somebody explain to me the advantages and disadvantages of capillary pressures during a water flood process.

Thanks..

[vinomarky]

To say there are advantages & disadvantages of capillary pressure is not really correct. Capillary pressure exists, and it has effects - those effects may help, hinder or be negligible to the process depending on the situation.

Probably best if you have a think about it yourself - what happens if a rock is water wet? What about one that is oil wet? What would happen when you try to displace oil out with water in each case?... hint, you'll generally have better response in one over the other....

Bonus question to ponder - in waterflooding operation, is the imbibition or drainage capillary curve controlling the behaviour?

[ELgharib]

Thank for your help....Are you a lecturer? I did some research with SPE series EOR(chap2) but will be happy if you can clarify this to me. I am not a lasy boy by the way..Just want to make it clear in my mind forever.

Regards

[vinomarky]

I'm not a lecturer - these are (IMHO) pretty fundamental concepts that the practicing reservoir engineer needs to have clear in their head, and the best way to do that is to think them through rather than memorize - hence my hesitance to immediatley give the answer

Think of what happens when a rock preferentially 'likes' water over oil, in a situation where you are trying to displace oil out of pore spaces - do you think water will imbibe into the rock easier and/or be less likely to finger/bypass oil than if the rock preferred being coated in oil?

[ELgharib]

Thanks for your time once again.
In fact, I was confused by the microscopic and macroscopic waterflood process. The water tends to trap oil as ganglia and at the same time oil have a good relative permeablity in a water wet rock. So in IOR we need to reduce the IFT and in a Waterflood the capillary forces helps with a good Relative permeability, avoiding fingerings. The 2 effects are almost opposite at a microscopic and macro....

Correct me if I am wrong.

[soman703]

In a waterflood its predominantly, Imbibition!