The oil and gas industry demands robust integrity assessment methodologies to ensure safe and efficient well operations throughout their life cycle. Casing and completion tubulars are critical barrier components that provide structural stability and containment, protecting both the wellbore and surrounding formations. These steel tubulars are subject to significant degradation mechanisms, including casing wear during drilling operations and corrosion caused by aggressive fluids such as CO₂ and H₂S during production or injection phases. These processes lead to wall thickness reduction and may compromise the structural performance and integrity of the well. This work assesses the structural integrity of corroded and worn tubulars through three-dimensional finite element analysis (FEA) integrated with ultrasonic inspection (USI) logging data, with simulations conducted using Abaqus, supported by Python scripting. The proposed modeling captures the interaction between different damage morphologies – such as uniform and localized corrosion – and their effect on the structural response under combined loading conditions. USI data is utilized to identify critical sections by characterizing corrosion damage along the inner wall [1]. These measured data are incorporated into nonlinear 3-D FEA models to evaluate resistance envelopes under combined loading conditions, including internal and external pressure, and axial loads, capturing instability and failure mechanisms. An elastoplastic formulation with nonlinear hardening is adopted to describe the material response, and the Riks method is used for the nonlinear analysis. The models are validated against API/TR 5C3 [2] design equations for intact tubulars and benchmarked against DNV-RP-F101 [3] and ASME B31G [4] for corroded conditions. A consistent 3-D representation of combined corrosion and wear is proposed, addressing a gap in the literature for casing and tubing applications. The framework enhances the identification of critical zones and supports lifecycle integrity assessment and decision-making from design to life extension, well reuse, and CCUS applications, contributing to safe offshore well operations.