Saturation height modelling

[yasiobasio123]

Hi.
I am doing masters thesis, i am using data from wells producing oil.

can one help me to know about:
1. how we determine the height above free water level (FWL)?
2. if capillary pressure data not available, how to find Pc?

An urgent reply needed.

Thanks.

[vinomarky]

2. Capillary pressure in the reservoir is a function of difference in fluid gradients and height above FWL, nothing to do with lab Pc

1. If you have lab Pc data, fitted to (for example) perm, then you compare your log derived Sw vs your calculated Sw from Pc relationship and vary FWL to get a match. It can also simply be a spill point depth or a point where (accurate) Sw logs show 100% water... Use judgement based on information you have at hand and estimated reliability

[yasiobasio123]

Thanks
You mean Pc=h(watr grad - oil grad) ?
Suppose the FWL is at 2500 MD. and top of oil pool is 2500 MD. How to find the height (h)?
Please be specific about to find h.
Thanks again and looking forward.

[vinomarky]

If FWL = 2500TVD and crest of oil pool is also at 2,500TVD, then you have no h and no oil pool

h is the difference in height between the FWL and the point at which you want to calculate the capillary pressure. What you are essentially calculating is buoyancy pressure. Think of it like the opposite of taking a empty drum under the water. As you take the drum deeper and deeper, there is more and more pressure on the drum

In your case, as you fill up more and more oil coumn, the pressure at the top of the column due to the surrounding water gets higher and higher.