Smart pigs are intelligent by design. They are equipped with electronics and different kinds of sensors used to answer various questions such as, "are there any defects in this pipe we should know about?"
The overall process of a smart pig operation looks something like this: Goal Setting (Figuring out what questions need to be answered), Preparation (picking components needed to achieve the goal such as which sensors will be used as well as choosing the type of pipeline pig), Pig Launch, Data Collection, Pig Retrieval and Data Interpretation.
It's important to note that data is not transmitted in real-time. The combination of thick steal and being underground most of the time doesn't allow for communication while in operation, which also prevents satellites from picking up a signal if they were to utilize GPS. Data is generally interpreted after a successful smart pig launch and retrieval.
There are a couple of ways a team would interpret the location of problem areas. Data may be interpreted from odometers and tilt sensors to determine exactly where a defect may be. They would then be able to tell a defect may be located at mile 4 and turn 72. Problem locations can also be identified by external sensors which can use magnets to detect the time a smart pig may pass.
What kinds of sensors and electronics might you find in a smart pig? It is important to note that depending on the goal, different sensors and mixes of sensors can be attached to perform the needed tasks.
Pigs travel through the pipes freely using the natural pressure inside the pipelines that move the materials like crude oil through the line. Pressure boosters along the way help maintain pressure through the long journey.
- Calipers (detect roundness)
- Tilt Sensors
- Capacitive Sensors
- Ultrasonics - the same technology found in Ultrasound Equipment.
Smart pigs are deployed through devices aptly named, Pig Launchers. Essentially, there is a pipe that holds the launcher branched off from the main pipeline. The launcher barrel is drained and then sealed off. The pig is then loaded through a hatch at the end of the pipe and closed. Through some fancy control settings they unseal the pipe and the flow of oil and pressure helps carry the smart pig to the next station where it is captured by a piece of pipe very similar to the launcher pipe. As you can imagine, this pipe works similar to the pig launcher, but is where the smart pig is unloaded. This section is called the pig trap.