Back pressure oa wells caused by a new Tie-In

[memo94]

Hello,

Our company has drilled some new wells and decision is made to connect the flowlines of these wells to a common header and this new header will be tied-in to an existing pipeline that is collecting the production of the existing wells.

I hae been asked to evaluate the back pressure that this new tie-in will impose on the existing wells.

I have simulated the case in HYSYS and in the PIPESYS extension added the SIDE-STREAM to Pipeline-Unit, but I can not get any effect on pressure, it just show some changes in tempreture and pressure upstream and downstream of Tie-In is the same.

Am I doing a mistake to use side-stream for this case?
Anyone had this kind of back-pressure simulation before?
How should I do this simulation?






Thank you,
Mehran

 

[zdas04]

How big are the wells (what percentage of the flow in the trunk)? Are they gas or oil wells? What was the velocity in the trunk prior to adding the wells? What is the velocity after adding them?

What you describe is possible, and happens fairly often in low-pressure gas when the trunk is running at less than 30 ft/s and you add enough gas to increase it to less than 40 ft/s you probably won't see a measurable change in the dP.

"Reasonableness" is one of the most important parts of hydraulic modeling. Computer guys used to say "if it is on green and white [paper] it is right", meaning that people tend to accept computer output uncritically. It is crucial to take a look at the results and ask "is this possible/reasonable?" Often the answer to that question requires considerable experience with piping systems and with models.

There have been many threads in these fora talking about the effectiveness of using HYSYS for pipeline modeling. I fall in the camp that HYSYS is great for process simulation, but the piping modules are more interested in getting the fluids from process to process and are generally good enough for plants but fall short in reproducing cross-country pipeline hydraulics. I'm not familiar with PIPESYS so I don't know if it is a reasonable tool or not.

David

 

[BigInch]

Sounds like you are modeling the pipeline system, but not modeling the well. You should be able to enter the pressure-flow curve for the wells, if you have that information. If you don't have the well flow curve, you must model the wells to get it for input into the pipeline hydraulic analysis.

http://virtualpipeline.spaces.msn.com