Introduction
In this part we will consider two cases of pipelines carrying oil
- In the first case, we consider a single pipeline which is carrying oil from a platform to a terminal – Sub-sea Pipeline
- In the second case we will consider two cross country pipelines connected together by a short pipe – Cross Country Pipeline.
We will also introduce some of the basic ideas of manipulating graphs. This aspect is discussed in more detail later in this manual.
2. Sub-sea Pipeline Modelling
This example is based on some pioneering work done by ZADCO in Abu Dhabi. The paper based on this pioneering work is reproduced as the appendix to this part of the manual.
In this problem we demonstrate three aspects of modelling
· Creation of a user defined pipe schedule
· The effect of valve closure and closure time
· The effect of a pipe rupture
A summary of the data is shown below, along with dialog boxes and description of the results.
2.1. Network Data
Initialisation Data
Units Metric, with m3/hr for flow rate. As it is essentially a combination of units it is necessary to employ user defined units.
The actual units used are shown below:
\Simulation time 0 – 240 sec (this will be increased to 360 sec for simulations 4 and 5)
Pipe Schedule Data
Pipe Type In this problem we use a user defined pipe schedule. The user defined pipe schedule data in this case is shown below:
Pipe schedule name - Special steel
Pipe roughness - 0.0457 mm
Poisson’s ratio - 0.33
Young’s modulus - 227.9 Gpa
Pipe diameter data
Nom Size, mm
Inner Diameter, mm
Outer Diameter, mm
In order to input this data click on Libraries, Pipe Schedule and then double click on End of Data. Enter data into dialog box as shown below:
After completing the dialog box, click on OK, this will close the list box.
All the library files are stored in a separate file with an extension ‘.Lib’. The PIPENET VISION automatically saves the library file once the Sunrise Data File (.SDF) is saved. The name assigned to the Library file will be that of the name given by the user to the Sunrise Data File.
Initialisation Data (Fluid properties)
The liquid properties are shown below:
Density - 877 kg/m3
Viscosity - 6.8 Cp
Bulk modulus - 1.5GPa
Vapour pressure - -0.996263
Enter the fluid properties by selecting Fluid… under Init, and completing the dialog box as shown below.
Pump Data
The pump curve data to be used is shown below:
Flow rate, m3/hr
Pressure, bar
0
57
6000
52
8000
50
10000
47
12000
41
The dialog box for this is obtained by using the commands shown below:
The dialog box for the pump curve completed is shown below:
Network Data
The network in the schematic form is shown below. Make sure that you input the pipes in the same sequence in order to consistent with the data table for pipes.
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