Description

Designed for you, if you are...

• A well engineer who wants to understand how mud weight recommendations are made and how well trajectory planning can reduce borehole stability problems as well as the likelihood of mechanical well failure in depleting reservoirs due to compaction and faults slip
• A geomechanist, petrophysicist, geologist or reservoir engineer who wants to understand how to estimate the geomechanical properties in the subsurface and select field development scenarios that minimise well-related project costs (by minimising drilling issues and well failure risks)

How we build your confidence

• Examples and case studies from different geological settings
• Exercises to develop some hands-on skills
• Quizzes to test knowledge transfer
• Discussions (Q&A) to help deployment of the learnings

The benefits from attending

• Participants will understand the concepts of stress & strain, tensile & shear failure, and linear elasticity and how that applies to wellbore conditions, covering the risks of borehole instability, fracturing, losses, and mechanical well failure, both under virgin, depleted and re-pressurised reservoir conditions.
• Participants will be able to identify field and experimental data to constrain the in-situ stress condition and formation properties and estimate their uncertainties. Among others, participants will understand the difference between field integrity test and (extended) leak-off tests, construct and interpret pressure-depth plots, conduct Mohr’s circle analyses, and understand the impact of mud weight and well orientation on borehole (in)stability.
• Furthermore, participants will understand how appropriate well trajectory planning can reduce the risk of well failure (unable to produce or re-enter) due to reservoir depletion and re-pressurisation (e.g., due to waterflooding or CO2 storage).

Topics

• Overview of project risks at well and field scale
• Workflow & subsurface characterisation
• Stress in the Earth & structural styles
• Pore pressure: Basic concepts & measurements
• Pore pressure prediction: Over-pressure & mechanisms
• Pressure in salt
• Vertical & horizontal (principal) stress, (X)LOT, etc.
• In-situ stress scenarios & pressure-depth plot

• (Principal) stress, Mohr’s circle
• Equilibrium and linear elasticity in 1D, 2D & 3D
• Strain, uniaxial and irreversible deformation
• Material failure, Mohr-Coulomb
• Elastic and failure properties from rock mechanical tests
• Properties from petrophysical logs

• Stuck-pipe mechanisms & prevention
• Stress distribution around the bore hole
• The role of mud weight, examples
• Bore hole failure: instability, lost circulation
• Polar plots: impact of dip angle and azimuth
• Oil-based vs. water-based muds
• Over-pressure & in-fill drilling
• Offset & other well data
• Workflow & recommended mud weight

• Building a 3D geomechanical model (MEM)
• Geological considerations
• Change of in-situ stress due to reservoir depletion
• Stress path coefficient
• Reservoir pressure re-pressurisation
• Reservoir and top-seal fracturing
• Thermal aspects, thermo-elasticity

• Drilling in depleted reservoirs
• Compaction, compressibility, subsidence
• Strain along the well path
• Compaction induced well failure
• Well failure due to slip layers
• Fault reactivation & induced well failure
• Well trajectory planning

• Developing the work plan
• Documentation of evidence