RISK-BASED INTEGRITY AND FATIGUE ASSESSMENT OF HIGH-PRESSURE MULTIPHASE PIPELINES IN SAUDI ARABIA: INTEGRATING ADVANCED STRESS ANALYSIS, AIV/FIV SCREENING, AND ASME B31.4/B31.8 COMPLIANCE

Abstract

Saudi Arabia is expanding gas, liquids and industrial pipeline networks while existing high-pressure assets continue to operate under severe desert terrain, temperature gradients, flow assurance constraints and increasingly complex multiphase production. These conditions make integrity assurance a coupled problem rather than a sequence of separate code checks, because static stress margins, corrosion allowance, vibration fatigue, construction quality, pressure cycling and inspection confidence influence the same probability of failure. This review develops a risk-based framework for high-pressure multiphase pipelines that integrates advanced stress analysis, acoustic-induced vibration and flow-induced vibration screening, fatigue assessment, defect management and ASME B31.4/B31.8 compliance. The aim is to synthesise recent engineering literature and standards from 2020 to 2025 into a practical decision model suitable for Saudi pipeline operators, engineering contractors and asset integrity teams. The paper applies a structured narrative review, comparing design-code obligations, fitness-for-service methods, in-line inspection technologies, corrosion and cracking prediction, and vibration integrity practice. The review shows that code compliance remains necessary but insufficient when multiphase flow produces slugging, turbulence, valve noise, small-bore branch excitation and local dynamic stress amplification. A robust assurance strategy therefore requires early screening, finite-element stress modelling, fatigue life estimation, risk ranking, inspection verification and management-of-change feedback. The proposed framework emphasises traceable assumptions, conservative data treatment, human expert review and staged escalation from screening to detailed simulation. The study contributes a Saudi-specific synthesis that connects compliance, risk and operational integrity, and it identifies research needs in validated vibration datasets, field-calibrated digital twins, Saudi environmental loading and uncertainty-aware fatigue models.