Results - Pipeline 2 Times Longer

Turndown Curve

We do the same simulation for drawing 3 turndown curve as we did in the base case, and compare the turndown point  in these two different pipeline length geometry.

Here is the table of the position of turndown point  between two different pipeline length geometry.

    Base case (Pipeline L)     Pipeline 2L  
Turndown point 1 (1.26314, 0.77) (1.2228, 0.777)
Turndown point 2 (0.8634, 0.517) (0.8634, 0.522)
Turndown point 3 (0.5792, 0.332) (0.5792, 0.341)

By comparing the turndown points for these two different pipeline length, it is clear that these points are basically the same.

The following figure gives us a distinct seeing by joining two turndown curve (Turndown Curve 1) together.  

Although the left part of the turndown curve including the turndown point is almost the same, the transition point always need to be checked ( Turndown point =? Transition point or Transition point moves to left or right ).  


Looking for transition point

  1. Run simulation for each transition point, if it is not severe slugging, directly move to the left point, if it is not sure, run the simulation for the left point and right point.
  2. Export all the data in Ledaflow to Matlab and do the same comparison as the base case.
  3. Determine the transition point.


Drawing the flow map and comparing

Here is comparison of the transition line for two different pipelines, it is clear that the transition line of pipeline 2L moves to the right, and when we check the transition points with the turndown points, almost all the turndown points are transition points.

Why the transition line moves to the right when compared with the base case (pipeline 1L)?  Longer pipeline, which increase the gas buffer volume, and lower the gas/liquid ratio's, which reduce the pressure buildup rate in the pipeline, increase the possibility of severe slugging.