D437 Geomechanics for Unconventional and Tight Reservoirs (Distance Learning)

The first portion of the course will address the fundamentals of oil-field geomechanics, including stress, mechanical properties and failure. Common near-wellbore and reservoir-scale geomechanics applications will be introduced. The second part of the course will focus on the characterization of unconventional reservoirs (heterogeneous rock masses with the presence of discontinuities and weakness planes) and present the tools and models that can be used to optimize single- and multi-well hydraulic fractures in these intervals. Examples from a variety of unclonventional plays will be discussed. 

Part 1: Geomechanics Fundamentals

Module 0. Introduction to Unconventional Geomechanics

• What makes a good play – geomechanics point of view
• Unconventional Play scenarios
• What is geomechanics? Definitions, history, relevance

Modules 1 - 2. Principles of Stress and Strain - Field Stress Measurements

• Basic of stress-strain and Mohr circles - application of natural fractures
• Effective stress concepts, role of pore pressure
• Field stress variations, structural effects
• Stresses around boreholes
• Stress determinations

Module 3. Pore Pressure Evaluation

• Basic concepts and causes of overpressure
• Pore pressure analysis – Eaton, Bowers’, NCT, effective stress methods
• Analysis workflow
• Challenges in unconventional, field examples.

Modules 4 – 5. Mechanical Rock Behavior

• Mechanical properties, elasticity plasticity, poroelasticity, viscoelasticity.
• Failure in rocks, failure criteria
• Influence of faults and fracture, anisotropy
• Laboratory testing, measurements, interpretation
• Use of logs for mechanical properties, calibration, correlations.

Module 6.  Geomechanical Modeling and Workflows

• Concepts and tools
• 1D, 2D and 3D models
• Geomechanics workflows in unconventionals

PART II:  GEOMECHANICS FOR UNCONVENTIONALS

Module 7 - 8. Hydraulic Fracturing Fundamentals

• Basic, objectives, parameters
• Frac containment, net pressure
• Injection testing, DFITs
• Horizontal wells
• Perforating, Proppants – 100 mesh and proppant transport,
• Fracturing fluids
• Role of natural fractures. Injection zone selection

Module 9. Stress Shadows - Multi-stage Multi-well

• Mechanics of stress shadows
• Effect on multi stages and clusters
• Multi-well stress shadows
• Tip shear stresses, Modeling examples

Module 10. Rock Fabric Characterization

• Description and quantification of rock fabric attributes – cores
• Mechanical behavior, hydraulic behavior, testing in unconventionals
• Stresses - critically stress fractures and hydraulic conductivity
• Geometry and spatial occurrence, DFN models.
• Examples of evaluation in unconventional plays

Module 11. Shale Geomechanics

• Unconventional shale plays – shale types – challenges, critical issues
• Geological scenarios for completions
• Geomechanics of interfaces – HF interaction with interfaces, effect of fracture toughness
• HF models: traditional and advanced models
• Shale properties static and dynamics examples from different plays – elastic parameters, time dependency, frictional properties
• Shale and Shale like behavior – mineralogic content, shale and flow.
• Myths to debunk – brittleness, complexity, SRV and microseismic, sand volume per lateral length

Module 12. Hydraulic Fractures (HFs) and Natural Fractures (NFs)

• HFs propagation with NFs – effect of NF orientation
• Dual HF propagating in a fractured media
• Pressure Diffusion – coupled effects – stimulation benefits
• Interaction HF – NF - crossing rules.
• Influence of NF characteristics – Dense vs sparse DFN, stress anisotropy, NF connectivity, parametric studies. Modeling examples.
• Influence of operational parameters, effects of fluid viscosity, injection rates – injection time, 
• Influence of the stress field and insitu pore pressure on HF behavior.
• Microseismicity response with anisotropic stresses – dry and wet MS events. Effect of initial aperture of the NFs.

Module 13. Depletion – Refracs

• Depletion effects on HFs, depletion and in situ stresses.
• Parent - child evaluations, Cluster efficiency, drainage volumes
• Frac hits - types.
• Microseismic depletion delineation, Cube evaluations
• Refracturing – candidates, case histories, lessons.
• Geomechanics of refracs.
• Refracs economics, refrac activity, examples.
• Refracs methods, engineered refracs.

Module 14. Multi-well completions

• Zipper fracs, stress perturbations, induced shear around zipper fracs
• Interaction of HFs, overlapping HFs, models
• Zipper fracs stress shadows.
• Effect of multiple well completion in fractured rock mass – sheared fabric – friction angle effect, geometry of zipper fracs. Effect on fabric stimulation.
• Sheared length, pressure diffusion.

Module 15.  HF Monitoring and models (Extra session)

• Temperature Logs, strengths and weaknesses, procedures. Effect of wellbore and completion.
• RA logging procedures, strength and weaknesses, tracer applications
• Micro seismic monitoring – MS as a geomechanics issue. Events, field data, MS imaging, passive seismology, triggered or induced seismicity, array design, surface vs downhole, source mechanisms, SRV from MS and drainage volume.
• Tiltmeters- direct fracture monitoring, measurements, patterns, cases.
• DAS/DTS Basics, production estimations, cluster efficiency, integrated analysis.
• HF Models - advanced models fundamentals, input data, 2D models, pseudo (planar) 3D, Cell/Grid based models, lumped pseudo 3D, Fully 3D, HF reservoir simulators.