Perpustakaan Digital ITB

Ensuring the long-term integrity of perforated cemented well sections is critical for the success and safety of carbon capture and storage (CCS) operations. This study investigates the structural performance of perforated cement sheaths in CO? injection wells using Finite-Element Analysis (FEA), with a focus on how perforation phasing influences tensile stress accumulation and crack formation. The Goldeneye Field in the UK North Sea is selected as a case study due to its suitability for long-term CO? storage. A 3D finite-element model of the casing– cement–formation system is developed and evaluated under five years of time-stepped injection pressures. Simulation results demonstrate that compressive stress remains safely below the 35.8 MPa capacity of API Class G cement across all cases. However, tensile integrity proves highly sensitive to perforation design. The 45°/5 shots-per-foot (SPF) configuration induces sustained tensile failure, with crack widths exceeding 20 ?m and no observed recovery. The 60°/5 SPF case shows partial recovery but still maintains critical apertures, while the base case (90°/4 SPF) remains below failure thresholds. The findings reveal that tensile damage, once initiated, is irreversible under injection pressures typical of CCS operations, and can pose long-term leakage risks through microannuli. Conservative perforation designs and advanced cement formulations are recommended to mitigate failure. This study contributes a predictive framework for assessing well integrity risks in perforated CCS wells and supports improved perforation planning and zonal isolation strategies.