Further improvement of Magnetic Tomography Method (MTM) has led to the creation of a principle new approach in assessing the integrity of pipelines especially non-piggable or difficult to inspect (Syahnaz Azlin Razlan, Mohd Izuwan Ilmi et al., 2005). The analyzing of the developments and assessing the potential of the new technology in terms of the best compliances with market demands, the associates of the Magnetic Gradient Tomography Method and devices based on it have expanded the horizons of application of existing technologies. MTM-G has been developed with the objective of customization on the stress assessment through 3D data acquisition or 3D space measurement [Fig.1] and with further analysis that provide the ability to classify the mechanical stresses by types into the hoop, longitudinal and other various complex combinations (bending, twisted, shear stresses etc.) (Yong Bai, Qiang Bai et al., 2005). By having MTM-G, it will help the asset owner to know details about the pipeline behavior and its actual state under in-situ operation conditions.
MTM technology is well known as the approach of inspecting the technical condition of a pipeline by scanning and detecting magnetic field changes reflected from a combination of stress and defects without contact (S S Kamaeva, I S Kolesnikov, N A Eremin, L A Khusnutdinov et al., 2009). As part of the evolvement of existing technology, Magnetic Gradient Tomography Method (MTM-G) has been introduced to the market where it provides more benefit to the end user (Oilfield Offshore Services Sdn Bhd, Centre of Excellence (COE) – Petronas Carigali Sdn Bhd et al., 2022).
The technology retains all advantages of non-contact external inspection, is designed to assess the actual current pipeline state and risks evaluation and prognosis with more reliability and higher confidence.
MTM technology is a non-destructive method for inspecting and determining the technical state of ferromagnetic pipelines based on the evaluation of risk-factor (F) of anomalies - stress-strain state in the cross-section with respect to the changes in the magnetic field. The MTM method is founded based on the physics principles of ferromagnetism and the Villari effect or also called the magnetoelastic effect (RD 102-008-2002 et al., 2002; OOO "R&D CENTER" TRANSKOR-K et al., 2004).
