THERMO-POROELASTIC NUMERICAL MODELING OF CEMENT SHEATH STRUCTURAL INTEGRITY IN OIL WELLS

Abstract

This study proposes a thermo-poroelastic numerical modeling approach to evaluate the structural integrity of the cement sheath in oil wells. Positioned between the casing and the surrounding formation, the cement sheath is responsible for casing support and hydraulic isolation between permeable zones throughout the well’s lifecycle. Although thermoelastic models are commonly used in design practice, recent studies highlight that the porous behavior of hardened cement significantly affects its mechanical response under thermal and pore pressure variations. Analytical models provide valuable preliminary insights, but rely on simplifications that limit their applicability to real-world conditions. In contrast, numerical modeling enables more accurate representations of operational scenarios and stress distribution in the casing–cement–formation system. In this context, the methodology includes: (i) idealization of the physical model; (ii) characterization of the case study based on literature data; (iii) thermoelastic and thermo-poroelastic numerical modeling; and (iv) comparison of numerical results with analytical solutions. The results show excellent agreement with analytical predictions, with relative errors below 1.5\%, confirming the accuracy of the adopted numerical approach. Therefore, the proposed numerical model represents a significant advancement in the structural integrity assessment of cement sheaths, supporting safer and more efficient well designs.