nodal analysis of multi-layered commingled gas wells

[petelv]

Hello all,
I am currently trying to put together a new workflow for nodal analysis using prosper for multilayer commingled gas wells.
The analysis will only include wells that I have mplt data for so basically i know how much production is coming from each layer.
Has any one have ideas on how I may produce a workflow to identify the skin factor for each individual formation that has been measured in the mplt?
any insight/direction would be greatly appreciated!!

 

[zdas04]

You really have three choices: (1) send a really skinny guy downhole to look; (2) make up some data; or (3) run a spinner survey. The first one is not well received by the skinny guys of the world (or by the Health and Safety guys). The third one is pretty expensive and the data is a very small step better than a guess. It generally comes down to guessing. There are a lot of high-sounding terms for it, but at the end of the day the best you are going to do is a WAG. When you figure in the "accuracy" of the multi-phase flow correlations that Prosper uses, this particular guess doesn't really hurt the outcome much.

I reviewed the capabilities of the first nodal analysis program (SNAP developed by Amoco in the mid 1980's) and it was more of a Monte Carlo simulation than a deterministic model. It often led to very good decisions. Since then the industry has tried to make nodal analysis mechanistic. The interfaces have gotten much prettier, and the weasel words get shoved into smaller and smaller print, but the decisions I see people trying to make with the new programs leave me shaking my head. The more complex the wellbore, the more it is needed and the less value it really adds.

I have to add a disclaimer. The last version of Prosper I ran myself was in 2003. Since I retired, I've seen output from several runs but I can't be certain if the nonsense was inherent in the program or if it came from the users being less than expert in its use. It might have gotten better, but the math it is trying to do is kind of tough.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.