Production Allocation Method

[vinomarky]

I'd strongly advise GETTING more data

You may not have the data historically, but if you can arrange to have some orifice plates installed and/or conduct some allocation tests in your wells it will vastly aid the accuracy

The problem you face is that even if you characterize your VLP curves etc, you still need to make assumptions about the local reservoir pressure and kh around each of your wells - both of which are usually quite different between wells

Perhaps you can go to logs and (gu)estimate kh per well, then assume average reservoir pressure per well is the same - armed with this info you can draw an EWAG (Engineered Wild Ass Guess) as to an appropriate production allocation based upon WHP's. Start with WHP and observed fluid cuts, assume a rate (if friction is significant), from VLP curves calc FBHP, from (gu)estimated kh and Pr calc flow rate from Darcy (iterate if friction is significant). Because the absolute value is not as important as the relative values between your wells this would probably be a reasonable method to use - I am assuming here that your wells are flowing naturally. If you are pumping them then go to your pump parameters for allocation.

Another thing to check is that usually wells are occasionally shutin for periods. While they generally are not shutin for long enough for a true buildup, if you choose a standard shutin period (ie 12 hours/24 hours etc) that is often met, then plot the WHP of your shutin wells over time (you may well have to make estimates of the fluid cuts in the tubing) you may glean more information about connectivity, kh and pressure support in each of your well - your better kh wells will build up more rapidly, and your higher Pr wells will extrapolate a sqrt time plot to a higher point.