Gas Reservoir AOFP - IPR

[Bang Gaol]

All,
I'd like to discuss about the methods we usually use in determining the AOFP or IPR.
1. C and n method
2. Forchheimer
3. Pseudo-pressure.

I still have no more knowledge than using these method based on the pressure. Is there anymore certain conditions to use on of those methods? Pressure, temperature, viscosity, compressibility factor??? Can somebody share the knowledge, please.

I believe you can share more in this topic. Thanks.

Regards

[bu7ammud]

C and n coefficint used in Emprical Methods and at same time thr is a & b for theoritical method.. for calculating future and current IPR,

this all methods used in Well Testing.. such as,, deleveribility test, isochonal & modified isochronal test, flow after flow test.. etc

[Bang Gaol]

I still have no clear idea about what kind of conditions we must use one of those equations? I think it's not clear anough by only using empirical or theoritical (analytical) method. Because there's no such condition in the field context.
Everyone?

Regards

[paolomaldini]

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[MIROINE]

C&N method is purely empirical ... you should use them once you have a very good step rate test (you should be carefull on the pressure you select to calculate the C and N as this method applied only on PSS state... try to calculate the stabilization time)
however the forcheheimer is more related to the Darcy equation where you have deltaP= AQ^2+bQ ... (B represent the Darcy flow and A represents the deviation from Darcy flow due to turbulence) .... so A and B (logically) could be obtained without having test data (if you have permeability and D factor)

One big difference between them is that C&N doesn t take into account the Pseudo pressure (in other words C &N do vary with time ... as the pressure is declining... mu and Z factor are changing) however the new feature in forcheheimer can be writen in m(p) ... which will make them fixed for the entire prediction .....


To make it easy ... Forchehimer Pseudo pressure is more accurate