oil well performance, well creating during restart

[anuradha]

Hey all,

Can anybody help in evaluating oil well performance & water production.
When we starting oil wells its creating problem.Moreover when its start producing, oil and water production is decreasing.Earlier water used to increase & oil productyion was decreasing.
pls suggest any paper or book so that i can understand what an why exactly happening in this oil well.

[ELgharib]

Ur Pb is not well stated. Assume it is a water coning, what will happen when u shut the well in in and u restart it again.
Now assume water is produced through a fracture....what will happen if you shut the well in and u restart it again

Try to explain clearyly the kind of pb u have.

[anuradha]

thanx for ur response,
okie leme explain..
We have oil field and siw wells are there, out of which two wells are high water producing ( high water production has started after one and half year of oil production).
Earler when well was producinh oil and water, oil production used to decrease and water production was increasing.
but now oil and water production both has started decreasing.
I want to understand this behaviour.

[ELgharib]

Sound a bit clear now. The Increase of WCT associated with decrease of oil is a normal phenomenon.
The Reservoir/Sandface/Well is a system. If you have a production problem you should locate the origin start from the top (Well head=> choke) to identify if u have no restriction in the well. Assume you dont have any restriction, now you have the reservoir/sandface. You may have scale/fines at the sandface, and fines usually migrate with the onset of water production.
Look at the elements of your PI formula to help identify the pb that can easily affect the production. Reservoir pressure decline affects the Perm curves, and you will reach a mininmum where krw and kro crossplot. You need to go through this, and finally decide to perform a Pressure Built up test to find the skin and end up stimulating the well if the skin is high.

My first statement above deals with trend you observe every time your well is shut in, depending on the origin of the water your well sill start with higher or lower WCT.
Hope I have helped,

[anuradha]

hey thanx...

We do have scales in our oil reservoir, but i m not sure that scale formation theat payzone can be determined.These wells are getting water loaded due to high back pressure may be.Two three wells are flowing thru same riser.As u said i have to check the parameters.Actualy we dont have any individual metering for oil wells.Which equation can be used to identify water porduction and oil production from oil wells.So that in that increase or decrease in oil/water can be calculated.


Anu