About this Training Course

Geomechanical evaluations are about the assessment of deformations and failure in the subsurface due to oil & gas production, geothermal operations, CO₂ storage and other operations. All geomechanical evaluations include four types of modelling assumptions, which will be systematically addressed in this training, namely:

1.      Geometrical modelling assumption: Impact of structural styles on initial stress and stress redistribution due to operations

2.      Formation (or constitutive) behaviour: Linear elastic and non-linear behaviour, associated models and their parameters, and methods how to constrain these using

3.      Initial stress: Relation with structural setting and methods to quantify the in-situ stress condition

4.      Loading conditions: Changes in pore pressure and temperature on wellbore and field scale

This 5 full-day course starts with the determination of the stresses in the earth, the impact of different structural styles, salt bodies, faulting and folding on the orientation of the three main principal stress components. Different (field) data sources will be discussed to constrain their magnitude, while exercises will be made to gain hands-on experience.

Subsequently, the concepts of stress and strain will be discussed, linear elasticity, total and effective stress and poro-elasticity in 1D, 2D and 3D, as well as thermal expansion. Participants will be able to construct and interpret a Mohr-circles. Also, different failure mechanisms and associated models (plastic, viscous) will be discussed. All these concepts apply on a material point level.

Next, geomechanics on the wellbore scale is addressed, starting with the stress distribution around the wellbore (Kirsch equations). The impact of mudweight on shear and tensile failure (fracturing) will be calculated, and participants will be able to determine the mudweight window stable drilling operations, while considering well deviation and the use of oil-based and water-based muds (pore pressure penetration). Fracturing conditions and fracture propagation will be addressed.

Field-scale geomechanics is addressed on the fourth day, focussing on building a 3D geomechanical model that is fit-for-purpose (focussing on the risks that need evaluation). Here, geological interpretation (layering), initial stress and formation property estimation (from petrophysical logs and lab experiments) as well as determining the loading conditions come together.

The course is concluded with interpretation of the field-wide geomechanical response to reservoir depletion with special attention to reservoir compaction & subsidence, well failure and fault reactivation & induced seismicity. Special attention is paid to uncertainties and formulating advice that impacts decision-making during development and production stages of a project.

This course can also be offered through Virtual Instructor Led Training (VILT) format.