Use of low-frequency transmitters and locators in pigging and diagnostic of pipelines

Low-frequency electromagnetic transmitters and locators operate at a frequency of 22Hz. These devices are tuned in resonance with each other. The signal which they emit and receive can be described as a slowly fluctuating magnetic field which pass through pipeline wall , soil , wateror concrete structures practically without weakening by these substances. This paper describes low-frequency transmitters and locators principle of work and their usein tracking and searching of in-line smart and utility PIG moving inside oil and gas pipelines. It also shows the results of computer simulation for distribution of magnetic field by low-frequency transmitter in a variety of conditions. Some practical recommendations for installation of the transmitters to the PIG used in pigging and diagnostics of different pipelines. This paperalso contains description of main technical solutions used in the low-frequency equipment of Russian company "APRODIT" L.L.C. to adapt this equipment to different climatic conditions and to the specific conditions in the pipelines.
Materials and methods
Magnetically soft ferromagnetic materials, distribution of the magnetic field indifferent environments, computer modeling, electromagnetic resonance, analog and digital filtering of the useful signal from noise magnetic dipole field, Earth magnetic field
Results
In-line diagnostics and pigging are widespread in all countries with extensive network of pipelines. Low-frequency electromagnetic transmitters and locators are widely used in enterprises performingpigging and commissioning of different pipelines. These devices are designed, certified and manufactured to meet the requirements of explosion protection, reliability and serviceability.
Сonclusions
Properly installed low-frequency transmitter to Pig can monitor the movement and search stopped Pig almost any conditions. Modern low-frequency transmitters and locators to find and maintenance pigging are multi- functional devices that significantly improve the quality and reliability of the work onin-line clean-up and diagnostics.