The relationship between S_l and P_cap is not consistent with the van Genuchten function

Hi,

I am using ECO2N for simulating CO2 storage. I wanted to verify that the relationship between the liquid saturation, S_l, and the capillary pressure, P_cap, is consistent with the van Genuchten function used. In my model,

lambda = 0.457, S_lr = 0.0,  1/P_0 = 5.1e-5,  and S_ls = 0.999.

Then I tested their relationship using the following formula: 

P_cap = -1 / (5.1e-5) * ( (S_l/0.999) ^ (-1.0/0.457) - 1.0 )  ^  (1.0 - 0.457);

However, the resulted P_cap is not identical to that in the output file, and the P_cap becomes complex when S_l = 1.0.

I would be grateful if someone can help me on this issue?

Attached please find the model input/output files,  and an output file of the post-processing software ext.exe.

Best regards,

Jin