Section 4 - Pig Launching Facilities

Question 1

What is the main purpose of a Squeegee Pig?

Answer 1

For separation of different liquids or gases when pipelines are being filled or emptied, or when the same pipeline is being used for different products.

Can also be used for lightweight cleaning duties and dewatering gas pipelines.

Question 2

What is the main purpose of a brush pig?

Answer 2

For cleaning and dewaxing pipelines.

Question 3

What is the main uses of a sphere pig?

Answer 3

The sphere pig is used mainly to de-water gas pipelines, but is occasionally used for very light cleaning work on oil pipelines.

Question 4

What is the main purposes of the foam pig?

Answer 4

The foam pig is most often used for the initial de-watering and cleaning of pipelines. Any hard substances like welding rods are embedded as the pig passes by.

Question 5

What is the purpose of the foam brush pig?

Answer 5

The foam brush pig is used in lightweight cleaning services, usually on gas pipelines.

Question 6

What is the Kaliper or Linaiog Pig?

Answer 6

This pig uses two odometers to measure distance and a finger array to measure wall thickness or denting in pipeline sections.

Question 7

What is the correct Pig launching sequence?

Answer 7

1. Isolate Pig Launcher
2. Drain and Vent Pig Launcher
3. Insert Pig (Door Open)
4. Close Door.
5. Refill pig launcher and pressurise.
6. Set Pig Launch Indicator.
7. Open Main Pig Valves and Close Main valve slowly.
8. Pig Launched flag activated.
9. Reisolate Pig Launcher and resume main flow.

Question 8

What issues can be encountered when launching a pig?

Answer 8

1. Pig reluctant to launch.
2. Pig Breaks Up.
3. Stuck Pigs.
4. Foam pigs can leapfrog.
5. Pig launch and receive transmitter issues.
6. Huge incident potential.

Question 9

What are some key rules of pig launching?

Answer 9

1. Stick to procedure.
2. Double check assumptions.
3. Pig sizing must be correct.
4. Pig positioned correctly in launcher.
5. Reset the pig launch device.

Question 10

Where is the pig launching facility usually situated in an oil export system?

Answer 10

This is typically located as the last stage of the crude oil production facility and is the final item of equipment in the installation before the oil enters the main oil pipeline.