## 2 Methodology
### Operational Parameters for Each Inspection Technology  
For Guided Wave Ultrasonic Testing (GWUT), low-frequency guided waves (20-100 kHz) are employed for long-range inspections, enabling the detection of large-volume defects such as wall thinning, uniform corrosion, and weld anomalies. GWUT's effectiveness diminishes for small, localized defects (e.g., pitting corrosion), particularly at extended ranges or in pipelines with coatings and buried segments deeper than 1.5 m, where signal attenuation occurs. Soil factors, such as high moisture content, resistivity (<1000 \(\Omega\)-cm), and low pH (<6.0), exacerbate attenuation, reducing detection reliability.  
For Magnetic Metal Memory (MMM), variations in residual magnetic fields indicate stress concentration zones, which can signal early-stage cracks and localized corrosion. MMM's sensitivity is influenced by soil properties, particularly resistivity and moisture content, which can distort magnetic field signals in semi-buried or buried pipelines. The method is particularly effective in detecting stress concentrations caused by soil-induced load conditions, such as differential settlement or pressure points near joints and soil interfaces.  
In In-Line Inspection (ILI), Magnetic Flux Leakage (MFL) tools detect medium to large anomalies such as wall thinning, general corrosion, and mechanical damage with a sensor spacing of 2-3 mm. Ultrasonic Testing (UT) ILI tools achieve higher resolution with sensor spacing of 0.5-1 mm, enabling precise detection of pitting corrosion and stress-induced cracks. Soil-related factors, such as density, pH, and chemical composition (e.g., sulfates and chlorides), indirectly affect ILI performance by contributing to pipeline corrosion rates, which influence defect growth. To ensure optimal results, parameters such  
\begin{table}
\begin{tabular}{l l l l} \hline
**Criterion** & **Level** & **Score** & **Description** \\ \hline Aboveground Section Range & Low & 2 & Covers small areas or discrete sections (<10 m). \\  & Medium & 4 & Covers sections between 10 m and 1000 m. \\  & High & 6 & Covers extensive sections (>1000 m). \\ \hline Buried Section Range & Low & 2 & Covers small or discrete buried sections (<10 m). \\  & Medium & 4 & Covers buried sections between 10 m and 1000 m. \\  & High & 6 & Covers buried sections extensively (>1000 m). \\ \hline Market Accessibility & Low & 2 & Very limited availability, with minimal global presence. \\  & Medium & 4 & Moderately available, with limited competition. \\  & High & 6 & Widely available globally, with strong service support. \\ \hline Analysis Method & Qualitative & 3 & Provides location data but lacks precision in damage severity \\  & Quantitative & 6 & Quantification. \\  & & & Offers precise data, including severity assessment for informed \\  & & & decision-making. \\ \hline Inspection Procedure & Disruptive & 3 & Requires operational interruption or physical access adjustments. \\  & Non-disruptive & 6 & Can be performed without disrupting pipeline operations. \\ \hline Inspection Preparation & Minimal & 2 & Basic preparation such as calibration, with no additional steps. \\  & Moderate & 4 & Includes preparatory activities like cleaning or partial site \\  & Extensive & 6 & Requires significant preparatory actions, including infrastructure \\  & & & adjustments or site changes. \\ \hline \end{tabular}
\end{table}
Table 1: Rating Scale for Technology Performance Evaluation.  
as flow rate, pipeline configuration (e.g., consistent diameter), and piggability must be carefully specified.