Borehole integrity evaluation utilizing coupled hydraulic thermal and mechanical analyses in robust and pre-optimized finite element simulator

Abstract

A thorough understanding of stress distribution around wellbores is crucial for maintaining wellbore stability, especially in deep wells with complex trajectories and subsurface formations exhibiting coupled mechanical behaviors. This study introduces a new finite-element-based modular simulator designed to address a wide range of challenging drilling and boundary conditions, including the presence or absence of filter cake, high over-pressure, inhomogeneous and anisotropic formations, non-linear constitutive behavior, and deviated wells. The simulator uses finite element modeling to provide accurate stress predictions without the overly conservative assumptions common in existing commercial tools. Each module is pre-tested and validated against published analytical solutions and features a user-friendly interface with minimal input requirements, allowing for quick and robust simulations in both 2D and 3D configurations. The simulator can analyze various phenomena, including time-dependent pore pressure diffusion, temperature-induced stress variations, and the impact of heterogeneous formations and layering on stress concentrations. All pre-tested modules run in <60 s on a mid-range workstation while matching analytical solutions to within 0.2 %. We present several case studies that demonstrate the simulator's advantages over existing commercial tools, with all modules made openly available to facilitate broader application.