How to Generate Relative Permeability Curve Data

[Feldy Riza]

Hi guys!
I new in the page so I hope you can help me.

I am working on a reservoir simulation project of a very old reservoir which missing a lot of important data. I am looking for a correlation to generate an oil-water relative permeability curve.I have the original SCAL data but it is considered unreliable since it is strongly oil wet while the production data show's that it produced more oil and less water.

The sets of data that I have are:
1. Sor, and Swc after displacement (SCAL).
2. Capillary Pressure set curve.
3. Routine core data

I dont have an access to donwload from SPE papers now, I really appreciate if you can help me.


Regards...

Feldy Riza

[vinomarky]

Start with your endpoints, assume range of corey exponents (oil wet & water wet) - put into your model and find the ones that come closest to matching your history

The problem is that you state you can't trust your SCAL, so you really are reduced to retrofitting (history matching) a set of curves that yields appropriate behaviour. Note: Depending upon aquifer strength, proximity & volume of production, just because you've produced mainly oil does not necessarily mean you have not got an oil wet system - it could simply mean that water is too far away, or you haven't produced enough volume to bring it in yet

[Yengineer]

Mehdi Honarpoeur is an authority in this field.

[link Point to another website Only the registered members can access]

[itag]

Advie to start with endpoints is sound.
I'd also suggest try to organise/analysis what data you have to decide if its reliable or not.

eg does the Swir implied from cap pressure match/agree with Swc used in SCAL kr tests ( if not why not /)
If you just wanted 1 rel perm curve - once way to start is to define:
S* = (Sw-Swc)/(1-Swc-Sorw) where Swc and Sorw are endpoints and
krw = Ew.S*^nw
kro = Eo. (1-S*)^no

Ew and Eo are relperm y-axis endpoints and nw, no the Corey exponents.
If your reservoir was strongly water wet - usually Eo=1, nw=4 and no=2 ( or thereabouts) and the kr crossover point is greater than Sw=0.5. Ew tend to be in range 0.2 to 0.4.
For strong Oil wet it flips around ( no=4 nw = 2 etc) and the crossover point Sw < 0.5.

THere are other cluses for water wetness ( Amott and USBM indexes - and/or looking at 2nd drainage & 1st imbibition Pc curves - if you've got them). It is 'normal' for lab cleaning to make samples water-wet - which is why aging/restoration processes are usually followed.

One of the biggest simulation cluses to wetness is whether you need to raise the krw endpoint ( for water injection) to get wellbore pressures in injectors to match. This may suggest mix to oil wet. If so then kro may need to be lowered.

Hornapours book is good - but the so-called modified Corey curves tend to be what engineers actually end up using ( and or fitting to data ).

hope this helps