GOR and pipeline pressure drop
GOR and pipeline pressure drop
(OP)
Hello everyone,
I was analyzing a pipeline design from a wellhead tower to a recipient separator. The objective was to see whether the GOR increase can lead to overpressure the downstream facilities as it will see more gas eventually (flare system).
However, the analysis indicated something quite interesting; increasing the GOR lead to increasing in the pressure drop (i.e.: downstream facilities would face lower pressure each time!). This was against my intuition as I thought the opposite may occur. Anyway, when looking at the two-phase flow regime map, it seems that having high GOR pushed the wellfluid beyond the slug flow regime (bubble flow regime). Still I am trying to make sense out of it, but I am having difficulty analyzing this.
Could anyone help me with this?
Thanks
I was analyzing a pipeline design from a wellhead tower to a recipient separator. The objective was to see whether the GOR increase can lead to overpressure the downstream facilities as it will see more gas eventually (flare system).
However, the analysis indicated something quite interesting; increasing the GOR lead to increasing in the pressure drop (i.e.: downstream facilities would face lower pressure each time!). This was against my intuition as I thought the opposite may occur. Anyway, when looking at the two-phase flow regime map, it seems that having high GOR pushed the wellfluid beyond the slug flow regime (bubble flow regime). Still I am trying to make sense out of it, but I am having difficulty analyzing this.
Could anyone help me with this?
Thanks





RE: GOR and pipeline pressure drop
It is all about the energy, and the energy at a given point will change many times a second on a random sequence. CFD models do a slightly better job at representing this non-steady-state flow, but they are still +/-50% of actual pressure drops. It is very enlightening to set up a flow loop and inject enough gas and water to give a meaningful GOR. The chaos is inspiring.
The model you ran is possibly sometimes in the right direction, but it is also very possible that there will be periods during a given minute when the model is exactly wrong. Putting any faith an in CFD of multi-phase flow is quite risky.
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.
RE: GOR and pipeline pressure drop
Thank you for your quick reply. The model I ran was an OLGA model FYI
So what you are trying to say is that there is no general trend with the GOR versus pressure drop relationship?
RE: GOR and pipeline pressure drop
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.
RE: GOR and pipeline pressure drop
For all its worth i think you are being too pesimistic! The company i works for runs several long sub sea multiphase tie-back, and the accuracy of these models we find to be sufficient for pipeline sizing and solving ceratin operational problems. The OLGA model is not SS although a SS version do exists.
So aalshaiba now you have two different opinins from either side of the spectrum. Although, i would never say that the model is pefect and that you can use it for predicting the exact flow and pressure at a given time. But it will give an indication of design parameters and operating envelope.
Best regards
Morten
RE: GOR and pipeline pressure drop
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.
RE: GOR and pipeline pressure drop
Best regards
Morten