GWC determination using pressure gradient method

[alali]

Dear All
I want to determine the Gas-Water contact in a reservoir but I don't have any pressure gradient data in this interval
I have a DST test (pressure point) just about 5000 ft above this reservoir!
my Question is that how can I find GWC in this reservoir using gradient method and what is the methodology in these cases?
and what is the role of pore pressure and fracture gradient in this method?
because I may have these two (pore pressure and fracture gradient) values.
Thanks in advance.

[vinomarky]

You need at least one pressure point in each of the connected hydrocarbon and water columns, even assuming gradients.

Ideally you'd have two or more pressure points in each in order to reduce the uncertainties associated with assuming gradients

[vinomarky]

Dear Vinomarky
thank you for your attention in this matter
actually I have a pressure point @ 3550 m with 5760 psi in gas zone (pore pressure for gas I think!)
assume a water gradient about 0.48 & water density about 0.67
assume a gas gradient about 0.01
assume fracture gradient about 0.8

how can I find a contact in another reservoir in about 5000 m?

please help me in this matter
Regards

As stated already, you need a pressure point in the water leg. There is a reason that a big part of appraising a field is finding where the water leg is. Failing that, the best you can hope for is assume the water leg is in hydraulic connection to a regional aquifer for which you know where the water pressure gradient lies.