Capillary Pressure calculation/estimation

[Bilal Amjad]

Is there any way to estimate Pc curves for Oil/water and Gas/oil , n 3 phase system if relperm set is provided.

[FANARCO]

Yes you can. Even i you don't have Relative Permeability set.
From open hole logs you can estimate the Pc.

How ?????

In the transition zone Between Water and oil apply the equation Pc= (water sp. gr - Oil Sp. gr.) x H

Consider the value of H is zero in the free water level which is 100 % water saturation at that level and below.
And H in feet is the hight for each point above the OWC

H in feet and P in Psi

If you have your Log data you can share so, we can investigate further

[Bilal Amjad]

thanks alot , but i already know this method and J-function,
What for hypothetical model from scratch?

[Bilal Amjad]

I dont have any log data, just have Rel perm set

[FANARCO]

Is it including Pc curve ?

[Bilal Amjad]

no Pc curve, Just krw, krowg, krog, krg

[FANARCO]

Okay, you cannot generate Pc from relative permeability curves.

[Abdelkader]

Bilal,
I would follow the advise of Fanarco, having not the saturation data especially for water you won't be able even to use the J function equation as it needs the Swirr for calculations.
If you have have the Sw distribution along with your Rel Perm values you can do the computation by estimating the surface tension to 23,7 dyne/cm (or mN/m) which is an average value for most of reservoirs (85

[alif98]

Is there any way to estimate Pc curves for Oil/water and Gas/oil , n 3 phase system if relperm set is provided.

I never see any "direct" method of doing it. But you can use network model to match you relative permeability and it will produce capillary pressure curve set. It's a bit tricky with 3-phase system as the effect of hysteresis will add the complication.

[FANARCO]

Is there any way to estimate Pc curves for Oil/water and Gas/oil , n 3 phase system if relperm set is provided.

I never see any "direct" method of doing it. But you can use network model to match you relative permeability and it will produce capillary pressure curve set. It's a bit tricky with 3-phase system as the effect of hysteresis will add the complication.

Could you please explain what do you mean by Network?

[Abdelkader]

I guess Alif was thinking of neural network as numerical method to predict Rel Perms.

Regards,
Abdelkader

[alif98]

Is there any way to estimate Pc curves for Oil/water and Gas/oil , n 3 phase system if relperm set is provided.

I never see any "direct" method of doing it. But you can use network model to match you relative permeability and it will produce capillary pressure curve set. It's a bit tricky with 3-phase system as the effect of hysteresis will add the complication.

Could you please explain what do you mean by Network?

What I mean with network modelling is a way to represent porous media as a collection of pore and throat and using Young-Laplace equation, we can simulate a pore displacement in pore scale, enable us to calculate relative permeability and capillary pressure curve.

A lot of work has been done in network modelling basically in two direction:
1. Pore modelling, using thin section and computer modelling to create a 3D pore network.
2. Displacement mechanisms: three-phase flow, polymer flooding, irreducible saturation etc.

A good work from McDougall, Cruickshank and Ken Sorbie can be read from SCAWEB which basically anchoring network model to lab measurement.

[Bilal Amjad]

thanks all, I need Pc curve just for hypothetical study purpose, the way alif telling to estimate Pc sounds expensive, but applicable. thanks again.
the first post by Abdelkader is very helpful in my case.