why do we do pipeline inspection
a pipeline is the main equipment in the oil and gas industry. the pipeline functions to channel a fluid (e.g hydrocarbon) from one station to another station. at the start of the design, the pipeline engineers analyze the possibility of corrosion and other possible failures that can occur in this pipeline. then the pipeline engineer added a corrosion allowance to anticipate the corrosion that would occur during the operation of the pipeline. at the time of operation, the asset integrity team created a pipeline inspection program to determine the actual corrosion that occurred, whether it was in accordance with the initial estimate or not.
ultrasonic pipeline inspection
The asset integrity team worked together with the inspection team to blind inspection plans and determine the inspection method that was most suitable for each pipeline. This inspection program is stored in software that we know as a CMMS. There are many pipe inspection methods, for example, ultrasonic pipeline inspection, ILI, visual inspection, LRUT / GWUT, and others. the easiest method to use is ultrasonic pipeline inspection using UT handheld to determine the thickness of the pipeline. UT is a non-destructive testing technique based on the propagation of ultrasonic waves in the material tested. Usually, very short ultrasonic pulse-waves with center frequencies ranging from 0.1-15 MHz, is transmitted into materials like carbon steel to detect material thickness or to find internal defect inside the material.
advantages of Ultrasonic pipeline inspection by UT handheld
- Sensitive to discontinuity on the material being tested
- have a better or higher range for discontinuity detection than other NDT methods
- simple access from one side of material being tested
- High degree of accuracy in determining defect position,
- High degree of accuracy in determining estimated shape and size of the defect
- Simple equipment and easy to use, even for a new employee.
- Gives instant test results. No need to wait like on Radiographic testing
- can obtain a detailed description of test results
can be used as a measurement of material thickness, like pipeline wall thickness, pressure vessel wall thickness or Tank wall thickness.
Ultrasonic Flaw Detection
Ultrasonic Flaw detection is used to determine a defect in the pipeline, such as a crack on a weld joint. Most ultrasonic flaw detection applications use frequencies between 500 KHz and 10 MHz per second. At frequencies in the megahertz range, sound energy travels easily via most common materials and liquids but does not pass efficiently via air or similar gasses. Also, sound waves of different types travel at a different rate of velocities. For ultrasonic flaw detection, standard transducers employ an active element that is made of either a polymer, composite, or piezoelectric ceramic. When an electrical pulse of high voltage is applied to this element, it vibrates through a particular spectrum of frequencies and produces sound waves. When an incoming sound wave vibrates this element, it produces an electrical pulse.