11 OLGA Exercise-3

1 Ex Exer ercis cise e 4 GAS GAS COND CONDENS ENSATE ATE PIPEL PIPELINE INES S In this exercise, a gas-condensate pipeline through hilly terrain will be simulated. The fluid property file is condensate00.tab.  The pipeline elevation profile has been tabulated as x-y coordinates in the the file file “geo “geo.x .xy” y”.. Fo Forr this this part part of the the exer exerci cise se,, the the buil builtt-in in Gr Grid id Generator will be applied to generate the geometry input for the OLGA input file. 1 Task ask 4. 4.1 Us Using the Gr Grid Gen Generat erator or Start OLGA-2000, load the prepared input file ex4.inp and start the Grid Generator. When the file is loaded you start your work by pres pressi sing ng the the XY butt button on in the the Gr Grid id Gene Genera rato torr main main wind window ow.. Generate a new pipeline geometry based on the measured xydata data cont contai aine ned d in the the file file “geo “geo.x .xy” y”.. How? How? Fo Foll llow ow the the cour course se instructor step by step.  The information you will need in the Grid Generator session is as follows: Geometry designation SIMPLIFIED Pipe I.D. 19 inches Pipe roughness 0.0018 inches Wall label WALL_1 Maximum length of pipes 2000 m Maximum section length 1000 m Min. number of sections per pipe 2  The following steps will guide you through the fastest way to generate a new pipeline profile. 1 1. Select Select the “XY” “XY” option option in in the the Grid Grid genera generator. tor. 2 2. Read Read the xy data data file file ”geo.xy ”geo.xy”. ”. Click Click “Next” “Next” to procee proceed d to the next step in the process. You can zoom in on parts of the profile by selecting shift-left-click once, dragging the mouse across a part of the profile to define the zoom area and repeat the shift-left-click operation. One shift-right-click will bring you one zoom level back. 3 3. Insert Insert 4 fixpo fixpoints ints so so that that the xy profi profile le is divid divided ed into into 5 segments. Proceed with the “Next” button. 14. Simplify “Profile Segment 1”. You are now starting the process of setting up a simplified pipe profile for the first profile segment. - Click on "Insert Default Values" - Enter 2000 in "Use Pipe Length" (which is not the default) - Click on "Run" and check the angle distribution - Select "Full Calculation" and click on "Run" again 1 -W Whe hen n the the pipe pipe simp simpli lifi fica cati tion on is comp comple lete ted, d, you you can can remo remove ve the the algorithm-input window by pressing "Close". 1

5. Repe Repeat at step step 4 for for prof profile ile segmen segmentt 2, 3, 4 and 5

2 3 4 5 6

6. Select “Next” twice and create an OLGA Geometry with the input data as listed above 7. Select “Create” – you have created a simplified geometry 8. Select “Finish” 9. Select “File – Exit” 10. Wait in the GUI for the message "Grid gen finished"

Task 4.2 Gas condensate base case rates A geometry file has been generated for the “geo.xy” data, and an OLGA input file has been created based on this geometry. The file is named “ex4.inp” and the geometry is named SIMPLIFIED. The pipeline outlet pressure is 1015 PSIA. The fluid inlet temperature is 120 _ F. The wall thickness of the pipeline is 0.5 inches, the pipeline is buried and the ambient temperature is 3 _ C. The burial is modeled by adding two 1 ft thick layers of soil to the wall. Open ex4.inp and perform simulations with inlet flowrates of 20, 40, 60, 80 and 100 kg/s. Tabulate the inlet pressure and total liquid inventory of the line at each rate. The parametric study option is very useful for this task. Make a graph of the inlet pressure and the liquid inventory as function of flowrate (Excel). Try to explain the form of the inlet pressure curve.

Task 4.3 Pigging simulations Starting from the restart file for Task 4.2 at 20 kg/s, run a simulation of pigging the pipeline at 20 kg/s. Run the simulation for 100,000 seconds. Use the PLUG keyword to enter information about the pig. Input information required for the pig is shown below. Pig Data:

 TYPE = SHORT DIAMETER = 19 inches MASS = 275 KG STATICFORCE = 19000 N LINEARFRIC = 0. QUADRATICFRIC = 4750 WALL FRICTION = 9500 LEAKAGEFRACTOR = 0 INSERTTIME = 100 s Hints:  The pig launch and trap positions are defined trough the POSITION keyword. Define a launch position in the second section of the first pipe and a trap position in the second section of the last pipe. Add the plotting variables UPIG and ZZPIG to the TREND plot file. Questions:

1 1) Determine the volume of slug pushed by the pig, and determine if the speed of the pig is acceptable. 22) What pigging frequency should be used if a 7000 BBL finger-type slug catcher  is available?