44 PIPELINE TECHNOLOGY JOURNAL RESEARCH / DEVELOPMENT / TECHNOLOGY Stress Corrosion Cracking (SCC) is a well- known threat to the integrity of oil and gas pipelines. SCC is a damage mechanism that typically results in axial cracks on pipe- lines due to simultaneous action of tensile stress, potent environment (soil, coating, electrolyte etc.), and the pipeline material (poor microstructure). Small cracks are initially formed around the corroded area (Initiation) which tend to coalesce under the combined impact of applied stresses (pipeline hoop stress), cyclic stresses (pressure cycling) and residual stresses (bends, change in direction, and point of inflection). The coalescence process results in formation of large cracks also known as (crack colonies). The cracks propagate axially and radially under the action of poor environment (damaged coating, corrosive soil with electrolyte and insufficient CP to protect the external sur- face) and tensile stress (Growth). SCC remains a significant issue largely because the industry’s understanding of this phenomenon is still evolving and practical methods of ad- dressing SCC are not as mature as methods for addressing other failure causes. GENERAL SCC SUSCEPTI- 3. BILITY CRITERIA (ASME B31.8) SCC was found in Saudi Aramco pipeline network around 2006. Following this discovery of SCC, Saudi Aramco built on ASME B31.8S criteria for identifying SCC susceptible segments to prioritize its network to manage the utiliza- tion of the EMAT technology. The criteria were based on pipeline operating parameters, environment, age and con- dition. An Extensive Field Verification program was put in action that illustrated the capabilities of the EMAT ILI tools. Based on the ASME B31.8S criteria, 109 were selected for Crack Detection (CD) In line Inspection (ILI) in the period of 2009-2016. As a result, 26 pipelines only showed pres- ence of SCC. Based on the number of confirmed pipelines with cracks verses the inspected pipelines, Saudi Aramco identified a high need to enhance the SCC susceptible criteria to be more practical and applicable to SA pipeline network. This paper discusses in more detail how the Saudi Ar- amco enhanced the ASME B31.8S prioritization criteria. A statistical evaluation of the data compiled in the 1st phase of the comprehensive study was conducted along with the literature review. The Saudi Aramco used logistic regres- sions [1,2] to identify factors that increase or decrease the likelihood that cracking is present. The trends that were identified relate to coating type, pipe grade, pipeline age, diameter, thickness, metal loss, cathodic protection (CP) level, slope, and pipe type. The Saudi Aramco used the findings to profile crack susceptibility in the pipelines found with SCC and for the Saudi Aramco pipeline network as a whole to identify pipelines susceptible to cracking to include in the future ILI runs. PHASE 1 ESTABLISH A BASELINE The Saudi Aramco aligned a variety of data sets provided by Aramco against the centerline from the most recent in-line inspection (ILI) runs. The Saudi Aramco aligned multiple sets of ILI data by identifying girth welds within the datasets that match and then adjusting the locations of the features (rubber banding the data) based on their respective distances to those matched welds. Two align- ment spreadsheets were prepared for each study pipeline. The overlay spreadsheets were designed to quickly identify changes, such as an increasing or decreasing number of ILI calls over time, and correlations, such as the presence of metal loss near creeks and river crossings. The data aligned for the first spreadsheet (ILI overlay spreadsheet) included: • • • Elevation profile, locations of girth welds, casings, valves, sleeves, bends, and supports Cathodic protection readings ILI results from up to four of the most recent MFL, UT-wall, EMAT, UT-crack inspections (actual depths or depth classes for internal and external corrosion, mill related features, girth weld features, and crack-like features) The second spreadsheet (the general overlay spreadsheet) prepared for each of the study pipelines includes only the most recent crack and metal loss inspections (up to two total), the other information summarized above, plus the following information: Pipe diameter, wall thickness, grade, and coating type • • MAOP, cyclic pressure severity • Dig locations and dig summary information • • Field Verification Results (summaries of dig informa- tion) Topography information (locations of depressions, slopes, undulating areas, calculated from elevation profile) • Available Field/Operational data (e.g., soil type, when available) Figure 2 is an example of the first type of overlay spread- sheet (Figure 3 provides a legend), while Figure is an ex- ample of the second type. In the ILI overlay, the four in-line inspections included in the plot are results from a 2013 ultrasonic crack detection (UTCD) inspection in the top row, a 2014 MFL inspection in the second row, a 2011 ultrasonic wall thickness (UWD) inspection in the third row, and a 2008 corrosion detection pig (CDP) in the fourth row. The fifth row includes the elevation and cathodic protection data. The Saudi Aramco also created a dig summary spreadsheet that tabulates findings from the field and nondestructive testing (NDT) reports. Here, each entry in the spreadsheet lists the results from one set of NDT examinations in the field. The purpose of the dig summary spreadsheet was to provide