Comparison of Stress Initialization Methods in 3D Reservoir Geomechanics Models

ABSTRACT: Three-dimensional (3D) geomechanical models are crucial for subsurface characterization and engineering studies, including coupled reservoir geomechanics models, caprock integrity analysis, and compaction studies. Accurate stress initialization is essential for these models, as errors in initial stress states can negatively impact subsequent modeling steps. This paper reviews various stress initialization methods and highlights their application in both the oil and gas (O&G) and mining industries. We present a workflow that transitions from 1D geomechanics models using well logs to 3D models using numerical simulators. This stress initialization method involves applying "stress" (load or traction) boundary conditions or "strain" (deformation) boundary conditions and using a numerical simulator to calculate an equilibrated initial stress state. Case studies demonstrate the effectiveness of these methods in achieving calibrated initial stress states across different geological settings. Examples include the Lower Cretaceous Minagish Oolite reservoir in West Kuwait, the naturally fractured Matachín Field in Colombia and shale gas prospects in North America.