Numerical simulation of lateral mechanical characteristics of subsea wellhead in deepwater with novel expandable surface conductor

In deepwater oil and gas drilling operations, increasing water depth significantly diminishes shallow-soil bearing capacity while compromising mudline stability of surface conductors. Analytical findings indicate that lateral displacement and von Mises stress in surface conductors are predominantly localized within 15 m below the mudline. A novel expandable surface conductor design is proposed to enhance the lateral mechanical performance of subsea wellheads. A rock-soil mechanics-based analytical model was developed to evaluate lateral mechanical interactions between the conductor and surrounding soil, with particular emphasis on mudlineadjacent regions. ABAQUS numerical simulations investigated the influence of expansion material parameters (length, thickness, and position) on wellhead stability and soil disturbance. Results demonstrate that the expandable conductor reduces wellhead lateral displacement by more than 8 %, decreases von Mises stress concentration by 5 %. Parametric studies reveal that increasing the expansion material's length and thickness significantly enhances lateral stability. Optimal performance is achieved when expansion material is deployed within 10 m below the mudline. Field implementation guidelines suggest tailoring expansion material placement and dimensions to specific operational requirements, enabling cost-effective and safe deepwater well construction. This innovation improves bending resistance of surface conductor by 5-10 % while maintaining installation efficiency, providing a robust solution for deepwater challenges.