Explore advanced geomechanics concepts through this comprehensive university-level course delivered at The University of Texas at Austin. Master fundamental principles of continuum mechanics including stress tensors, principal stresses, Mohr circles, and deviatoric stress tensor invariants. Delve into elasticity problems by solving Navier equations for plane-strain scenarios and analyzing wellbore stability through sonic log interpretation for in-situ stress determination. Study the mechanics of saturated porous solids, covering particle-fluid interactions, poroelasticity theory, effective stress principles, drained and undrained loading conditions, and consolidation theory with applications to overpressure and stress path analysis during reservoir depletion. Examine inelastic behavior through failure criteria including Coulomb and Griffith models, plasticity theory with yield surfaces, post-peak behavior analysis, creep mechanisms, and grain crushing phenomena. Investigate open mode fracture mechanics using linear elastic fracture mechanics principles, PKN-KGD models, wellbore fracture testing, hydraulic fracture propagation in heterogeneous media, stress interference in multistage fracturing, and fracture behavior in unconsolidated sands. Analyze mechanical properties of various reservoir geomaterials including unconsolidated sands, shale, sandstone, limestone, and evaporites, while understanding scales and effective properties, heterogeneity and spatial variability, stress-dependent permeability, and laboratory measurement methods. Apply theoretical knowledge through practical projects involving stress log interpretation, fracture plane analysis, and mechanical earth modeling for real-world geomechanical challenges.

Syllabus

L01-1 Introduction to PGE 383, Overview Project 1: Stress Log
L01-2 Reading a Stress Log and the in-situ stress tensor
L01-3 Introduction to the stress tensor, principal stresses and principal directions
L01-4 Principal stresses and principal directions, Cauchy's equilibrium equations
L02-1 Principal stresses, tensor of effective stresses, lithostatic stress gradient
L02-2 General solution for vertical stress, vertical stress from logs and deviation survey
L02-3 Numerical integration for vertical stress, stress regimes
L02-4 Ideal hydraulic fracture orientation depending on stress regime
L03-1 Plotting a tensor? 3D Mohr circle
L03-2 Stress projection on fractures, stress decomposition in isotropic and deviatoric
L03-3 Stress tensor invariants, J2-I1 space, stress path concept, p`-q space
L03-4 Reservoir stress paths, 2D stress projection on plane
L03-5: 3D stress projection on plane
L03-6: 3D stress projection on plane (continued), shear and normal stress
L04-1 Summary Project #1, Intro Project #2: normal and shear stresses on fracture planes
L04-2 Transformation matrix from principal to geographical coordinate system
L04-3 Fracture and fault coordinate system, dip and strike
L04-4 Stresses on fractures, 3D Mohr circle and stereonet interpretation
L04-5 Placing a horizontal wellbore in a naturally fractured formation
L05 Project 3 1D MEM, solution to a continuum mechanics problem, kinematic and constitutive eqs
L06 Vertical Transverse Isotropy and isotropic elasticity, isotropic elastic 1D MEM
L07 1D MEM for hydraulic fracture containment, measuring Cij for VTI media,
L08 Anisotropic VTI 1D MEM, Solution to general continuum mechanics problem, FEM solution
L09 Plane strain solution of stresses around a cavity with FreeFEM++
L10 Wellbore stability, Poroelasticity: solid strain, porosity strain, energy of the porous solid
L11 Poroleasticity equations and the Biot coefficient, poroelasticity beyond effective stress law
L12 Drained problem of reservoir depletion: Total and effective stresses
L13 Undrained loading: diffusivity equation, examples and characteristic parameters
L14 Thermo-elasticity: application examples, theory, and uniaxial strain condition
L15 thermo-poro-elasticity and visco-elasticity
L16 Chemo-elasticity and introduction to plasticity
L17 Yield criteria and yield surfaces: Tresca, von Mises, Drucker-Prager and Mohr-Coulomb
L18 Failure surfaces: Coulomb and Lade; workflow for stability of deviated wellbores
L19 Plasticity theory: examples with Coulomb yield criterion and Cam-Clay model
L20 Introduction to plasticity with the Cam-Clay model
L21 Calculation of elastic and plastic strains with the Cam-clay model
L22 Wellbore breakdown pressure, ideal single and multi-stage hydraulic fracture geometry
L23 Linear elastic fracture mechanics and fluid-driven fracture models
L24 Fluid-driven fractures in porous media and multistage hydraulic fracture design
L25 Micro-seismicity, SRV, subcritical fracture propagation and hydraulic fractures in sand