Help needed with IPR/VLP matching in PROSPER

[zelje]

Hello all,

I'm looking for advice from more experienced users, because I'm not sure about the results I'm getting.

Well testing was done on a continuous gas-lift well. There were three tests, injection gas was the same - only surface choke was changed (6 mm, 8 mm, 10 mm). So we've obtained three different production rates (wellchecker) and bottom hole flowing pressures (slick line, T + P).

After entering data into the PROSPER's VLP/IPR matching screen, doing the estimating U value (seems allright), corellation comparison (beside 6 mm, results are resonable), and finally matching the VLP (P1 & P2 looks fine), i got the VLP/IRP graph like this.

[link Point to another website Only the registered members can access]
Do these VLP lines look normal? It seems to me, like software did some serious line bending there, just to meet the criteria; because VLP usually doesn't look like this.

Or, is this right for gas-lift VLP?
Or, did i do something wrong?

Please, if someone could clarify this for me, because I don't know what is right anymore.

THANK YOU!

[bond07]

Hope you seperated the loft gas rate from formation gas when entering the test data...what of your FTHPs for the tests? how do they look?...Did you/what kind of modifications did you do to your test data to match your PI if any?...

Throw more light on these then we can better address the issue

Sent from my HTC One

[zelje]

Hope you seperated the loft gas rate from formation gas when entering the test data...what of your FTHPs for the tests? how do they look?...Did you/what kind of modifications did you do to your test data to match your PI if any?...

Throw more light on these then we can better address the issue

Sent from my HTC One

Mr. Bond07,

First, I would like to thank you for your reply!

So definitely, this curve doesn't make sense?

After sleeping overnight, and before reading your post, I had decided to rule out the most troublesome test, one with 6 mm choke, and went matching with 8 and 10 mm.
These are the results:

[link Point to another website Only the registered members can access]
What do you think about curvature of this VLP? Does it make any sense for a continuous gas lift well?

The reservoir pressure is lower than bubble point pressure (cca. 107 vs. 150 bar, data given by reservoir engineers).
I've inputed following data into IPR/VLP matching screen:

GOR as (Total GOR - Injected GOR),
GOR Free as nil <- is this right, hm?,
and Gas Lift Injection Rate, as i got from the wellchecker.


About FTHP, the results are pretty the same for all of three tests; varying from 5-18 bars in each test (this is a bit odd, or is it because of the surface choke?)

Modifications for PI, or IPR, were done by reservoir engineers, but are not quite accurate because they haven't had valid input data - i.e.static reservoir pressure wasn't measured in years, not even now during this tests, just FBFP was made. During the matcing VLP sequence I didn't alter IPR values in IPR screen.

I would like to apologize for over-complicating,
but I would appreciate your advice!

THANK YOU!

[zelje]

Double post