Cement is critical to well integrity. It provides hydraulic isolation, preventing fluid flow between producing zones, ground water aquifers, and the surface. In steam stimulated wells, such as for Steam Assisted Gravity Drainage (SAGD) or Cyclic Steam Stimulation (CSS), the heat-up period places severe mechanical loading on the cement sheath. Heat is transferred from high temperature steam, through completion strings and annular fluids, to the casing, cement and formation. Thermal expansion of the casing combined with axial constraint make radial expansion of the casing the most severe in the energy industry. Furthermore, with constrained expansion of the cement, the range of deformations that must be accommodated by the cement sheath while maintaining isolation is challenging. These deformations can cause shear or tensile failure of the cement and result in leakage paths through the cement (e.g. cracks or global changes in cement permeability), or leave a micro-annulus when recovery has been completed and thermal operations halt. This paper describes the impact of key thermal and mechanical properties on the structural performance of cement blends in thermally stimulated wells. The work is based on laboratory testing of thermal cement blends and the use of Finite Element Analysis (FEA) to examine cement performance under operating conditions. The findings provide insight into important cement behaviours that impact longterm integrity of cement and highlight the significance of conducting tests under field representative conditions. Results indicate the importance of compressive strengths, flexibility, and shrinkage/expansion characteristics to ensure the cement sheath remains structurally intact during initial heat-up.

Horizontal liners in extended-reach drilling (ERD) wells can experience severe loading during running. Sometimes, downhole loads approach the limits of the tubular system and must be actively managed to ensure long-term well integrity. This paper describes a Canadian thermal operator's approach to managing installation and service performance of slotted liner and wire-wrapped screen systems in a steam-assisted gravity drainage (SAGD) application with unwrapped reach ratios approaching 13:1, and the associated evolution of liner running practices. The Operator's approach combines well-characterized liner body installation loading limits and a rigsite digital solution that leverages available measurements and a real-time torque-and-drag and tubular integrity monitoring system to inform the drilling team during running. Surface loads and rates measured by the rig are used as input to top-down torque-and-drag analysis to estimate downhole load distributions. Those downhole load estimates are then compared to the local loading limits of the liner at all depths. These local loading states (and their associated uncertainties) are integrated into a safe surface loading envelope that is displayed to the drilling team and updated in real time to support running decisions. The evolution of the Operator's running practices has provided a strong basis for confidence in protecting a critical tubular system, and over 250 liner runs have been monitored to date using the digital system. Prior to implementing the system, a conservative approach to managing downhole loads during liner running was used. The integration of a strong engineering basis for the tubular structure with top-down torque-and-drag analysis and uncertainty characterization has provided a running optimization basis and measurable indicators of tubular health that can serve as an enduring quality record and be referenced for the remainder of the well life. Forecasting of running loads and liner limits to total depth has also enabled early recognition of running challenges and opportunities for optimization. Interestingly, the edge-deployed digital system has also led to operational efficiencies during the running process. Running stages involving higher risk to tubular integrity are recognized early and treated with due care, as are opportunities for increasing the efficiency of certain parts of the running process. As the Operator considers longer-reach wells, the system also provides insights into likely running challenges and provides strong history-match datasets that provide a field-calibrated basis for predicting running and tubular integrity limits. The Operator leveraged a novel digital methodology for monitoring liner system integrity during well construction. The ongoing use of this system has allowed optimization of planning, real-time, and post-run practices, and provides a well-conditioned historical dataset for future well planning. The methodology has enabled the Operator to unify work done by drilling engineers, consultants, and the rig crew for optimal liner system integrity and running efficiency.