Geomechanics for Unconventionals - 2 Day Course - Training Course by Ikon Science

Geomechanics for Unconventionals - 2 Day Course

Available as a public course
Available as a private in-house course

Taught by Jorg Herwanger. The main geomechanical applications in this course will focus on fractures and hydraulic stimulation (fracture orientation and containment, re-activation of pre-existing fractures versus creation of new fractures, shear fractures versus tensile fractures, fault stability), and wellbore stability.

 The ultimate goal of a geomechanics course is to enable course participants to build geomechanical models and apply these successfully to field development issues. Given this is only a 2 day course it should be seen as the first step to achieve this wider objective but we  realistically expect course participants after attending the course to:

  • Understand the worksteps in building geomechanical models, and to be familiar in the theory behind these worksteps
  • Know what additional resources and standard textbooks can be used to build and apply geomechanical models
  • Have clarity in understanding in the assumptions in geomechanical projects, and be in a position to make a judgement on data requirements and input parameters. There will be ample discussion on assumptions made in different approaches to building geomechanical models
  • Read and understand geomechanical reports provided by service companies
  • Be able to challenge methods and assumptions in geomechanical reports with the report authors and have an informed discussion to improve the end result of a geomechanical project provide by a service company
  • Avoid the fate of becoming a person that unthinkingly clicks buttons in a software application to complete a workflow (“Nintendo-Geoscientists”). It is the aim of this course to impart understanding of Geomechanics that creates confidence in building and applying geomechanical models

The main geomechanical applications in this course will on fractures and hydraulic stimulation (fracture orientation and containment, re-activation of pre-existing fractures versus creation of new fractures, shear fractures versus tensile fractures, fault stability), and wellbore stability. The course time will be split in equal parts between (i) underlying theory, (ii) building and calibrating 1D wellbore centric geomechanical models and (iii) building, calibrating and applying 3D and 4D geomechanical models. Special emphasis is placed on using 3D seismic inversions as a data source (if available).

Full Course Outline

1. The three building blocks of a Geomechanical Model: (i) Mechanical properties, (ii) Pore pressure, (iii) Stress

2.  Mechanical properties

a. Using rock-mechanics testing data, we will

i.  Learn how to evaluate rock-mechanics tests data, and use these tests to define various terms in describing stress state and strain as a means of describing deformation

ii. Look at the definitions of mechanical properties needed in building a geomechanical model, and understand the units in common use

b. Using a large published data-set, we will

i. Create an understanding of principal controls on mechanical properties

3. Stress state – more than 30 ways of expressing stress.  Ordering the zoo of nomenclature in describing the stress state

a. Total stress, effective stress, stress tensor, principal stresses and many more

b. Stresses around a wellbore

i. Radial, tangential and axial stress

ii. Wellbore breakouts

iii. Tensile failure in the wellbore wall

iv. Inclined wells and inclined principal stress

c.Stresses on a plane

i. Normal and tangential stress on a plane

ii. Normal and tangential stress on a fault-plane or fracture-plane

iii. Critically stressed fractures

d. Plotting the stress state (Mohr circle plots, s1–s3, p’-q plots)

ii. Learn about upper and lower bounds of mechanical properties and get a sense for “reasonable numbers” for mechanical properties

c. Learn how to build a mechanical property model from well-log data using correlation functions

i. Which correlations exist

ii. What dangers lurk in using correlations functions and how to mitigate against creating a senseless property model

4. Geomechanics for Unconventionals

a. Poro-elastic equations in 1D

i. Interdependence of elastic properties, pore pressure and stress state

ii. What governs horizontal stress

iii. Relationship of poro-elasticity and empirical PP-FG (Pore Pressure – Fracture Gradient) methods, or “the right equation for every occasion”

b. Fracture orientation

c. Am I creating shear fractures or tensile fractures?

d.  First order controls on hydraulic fracture containment

e. Hydraulic stimulation: creation of new fractures or re-activation of pre-existing fracture and weak bedding planes?

5. Geomechanics for well-bore instability

a. Kirsch-equations describing the stress state near a wellbore

b. Examples and case-studies

6. 3D and 4D geomechanical models (Based on time and interest – additional ½ - 1½ days)

a. Building, executing and analysing 3D and 4D geomechanical models

i. Building a structural framework, mesh generation

ii. Property model

iii. Application of boundary conditions

iv. Stress field simulation and display of results

v. Stresses along wellbore and wellbore stability calculations

vi. Stresses on fault and fault stability calculations

b. When are 3D geomechanical models warranted, and under what circumstances a 1D geomechanical model is appropriate 

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