Rock typing in Petrel

[petengr]

hello All,

can some please give me an example how to an equations in the "calculator" in petrel, let suppose there is 3 rock types.

thanks a lot!

[vinomarky]

You have to be able to formulate an equation that distinguishes them

It may be as simple as a porosity cutoff for example assigning SATNUM array 1,2,3 to porosities <0.05, 0.05<PORO<0.15, and >0.15;
SATNUM=if(PORO>0.05,2,if(PORO>0.15,3,1))

It could be as complex as some sort of binned flow zone indicator index

Figure out the equation and program it. If you can write excel equations I'm sure you'll be able to figure out how to do it.

[petengr]

hi,

Please see the attached picture. If you got 3 rock types like the ones in the attached picture, and you got an equation representing every rock type, how can this equations be written in the calculator in Petrel, not Eclipse. Because as it can be seen in the picture, all the lines are covering the same range of porosity.

Thanks!

[vinomarky]

If you are trying to assign rock type /facie based upon poro/perm information such as that plot, then it's not too difficult, you just have to use more than porosity alone. Each of the curves for a given porosity are still unique if you factor in permeability

The image looks like classic FZI (flow zone indicator) type approach, which entails calculating FZI for each piece of rock (a function very similar to calculating J), then grouping values of similar FZI values. You never actually get a number of clearly defined lines like in the plot. Normally you plot your lognormal poro/perm information, and overlay it by colour defined by FZI value and look for groupings. From this you bin the FZI values into the major groups and classify them each as GHE's (global hydraulic elements) - sort of like facies based upon flow characteristics. You can find some background info at

[link Point to another website Only the registered members can access]
So, back to your initial question;

If you have poro & perm information and want to calculate FZI;
FZI = 0.0314 x SQRT(PERM/PORO) / ((PORO/(1-PORO))

If on the other hand you are given the values of FZI and porosity, then simply rearrange to get the appropriate perm for the FZI (see equation on page 4)

[petengr]

Thanks for the paper, very helpful one. However, the purpose of this RT is to populate a static model with horizontal permeability, based on already distributed porosity in the model. so with 3 rock types, 3 equation will be k fn(phi, and FZI), what condition in petrel calculator should be forced to avoid that the calculated k from each equation won't replace the values obtained from the other equations.

Thanks a lot!

[vinomarky]

IF(FZI=X1,PERM=Y1,IF(FZI=X2,PERM=Y2,PERM=Y3))

Substitute X1/X2/X3 with your values of FZI, and Y1/Y2/Y3 with the relevant equations.

If you indeed have values of FZI, then you dont even have to do the above, just calculate Perm directly as a function of porosity and FZI as already state in my previous post

[petengr]

IF(FZI=X1,PERM=Y1,IF(FZI=X2,PERM=Y2,PERM=Y3))

Substitute X1/X2/X3 with your values of FZI, and Y1/Y2/Y3 with the relevant equations.

If you indeed have values of FZI, then you dont even have to do the above, just calculate Perm directly as a function of porosity and FZI as already state in my previous post

Thank you very much!

[greathelp2]

Petrel 2010.1 c=r=a=c=k required in return abaliable , Peterel2009.1,Ki-n-g-do-m,Opendtect,interactive petrophysics,petromod