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Dynamic Data Analysis – v5.12.01 - © KAPPA 1988-2017 Chapte - p149/743
4.D.4.c Non-Darcy flow
As mentioned in the ‘Theory’ chapter, there are two main options to address non-Darcy flow:
using a rate dependent skin model or integrating the Forchheimer equation in a numerical
model.
Simulating non-Darcy flow with a rate dependent skin model
A rate dependant skin model may be used in the pressure and rate history simulation:
qdq ds S S
total ) / (
0  
The required parameters values are:
dq ds and S /
0
These values result from a necessary well test data analysis. The methods are developed in
the Chapter ‘PTA - General Methodology’.
Simulating non-Darcy flow with a numerical model
In a numerical model the (non linear) non-Darcy flow effect is included in the flow equation
through the value of the (non linear) non-Darcy flow coefficient,  which appears in the
Forchheimer equation:
2
u u
k x
P
    


 

It can be evaluated from the ‘Rate dependant skin’ linear assumption described above using
dq ds / with:
k
h r
dq ds w  

 
 
2
/
or from an empirical equation:
    5.0 5.5
1
005 .0
k Sw   
 