Modern intelligent or 'smart' pigs are highly sophisticated instruments that include electronics and sensors that collect various forms of data during their trip through the pipeline. They vary in technology and complexity depending on the intended use and the manufacturer.
Intelligent Pig
Source : https://www.nord-stream.com/media/picture_library/rgb_small/en/2013/08/intelligent-pig_3488_20130827.jpg
The electronics are sealed to prevent leakage of the pipeline product into the electronics since products can range from being highly basic to highly acidic and can be of extremely high pressure and temperature. Many pigs use specific materials according to the product in the pipeline. Power for the electronics is typically provided by onboard batteries which are also sealed. Data recording may be by various means ranging from analog tape, digital tape, or solid state memory in more modern units.
The technology used varies by the service required and the design of the pig, each pigging service provider may have unique and proprietary technologies to accomplish the service. Surface pitting and corrosion, as well as cracks and weld defects in steel/ferrous pipelines are often detected using magnetic flux leakage (MFL) pigs. Other 'smart' pigs use electromagnetic acoustic transducers to detect pipe defects. Caliper pigs can measure the roundness of the pipeline to determine areas of crushing or other deformations. Some smart pigs use a combination of technologies, such as providing MFL and caliper functions in a single tool. Trials of pigs usingacoustic resonance technology have been reported.
During the pigging run the pig is unable to directly communicate with the outside world due to the distance underground or underwater and/or the materials that the pipe is made of. For example, steel pipelines effectively prevent any significant radio communications outside the pipe. It is therefore necessary that the pig use internal means to record its own movement during the trip. This may be done by odometers, gyroscope-assisted tilt sensors and other technologies. The pig records this positional data so that the distance it moves along with any bends can be interpreted later to determine the exact path taken.
Pipeline defects include:
• General Corrosion
• Grooving Corrosion
• Small Pitting
• Girth Weld Anomalies
• Hard Spots
• Laminations and Hydrogen Induced Cracking (HIC)
• Erosion Wall Thinning
• Ovality
Intelligent Piggs can detect defects to an extremely high degree of accuracy, with the more advanced piggs able to detect depth sizing to within ±0.5mm, depth of pitting or corrosion to within ±1.0mm, and GPS location of defects to within 1.5m.
Types of Intelligent or Smart Pigs
Magnetic flux leakage (MFL)
• High and low resolution axial
• Circumferential (TFL or transverse flux inspection)
Ultrasonics
• Normal beam (wall thickness)
• Angle beam (cracks)
Inspection and Data Analysis
Inspection is carried out by using advanced ultrasonic, GPS, and magnetic technologies; able to identify even minuscule defects in pipelines.
Once data collection is complete, advanced data analysis can begin.
Due to the accuracy of data collected, only the necessary excavations, remediation, or direct inspections are completed; eliminating needless maintenance costs. The analysis identifies future risks to the pipeline, allowing for forward planning of upcoming maintenance.
Inspection Report Based on Pig's Component
Source : http://www.energyglobal.com/media/content/williamsonpigQandA.jpg
References :
https://en.wikipedia.org/wiki/Pigging
http://www.contractresources.com/content/services/intelligent-pigging
http://osfm.fire.ca.gov/pipeline/pdf/conference/inlineinspection.pdf
Dega Damara Aditramulyadi
Student ID : 15512046
Course : KL4220 Subsea Pipeline
Lecturer : Prof. Ir. Ricky Lukman Tawekal, MSE, Ph. D.
Eko Charnius Ilman, ST, MT
Ocean Engineering Program, Institut Teknologi Bandung
No comments:
Post a Comment