That is my presentation for my grad research about reservoir geomechanics, hope you find it useful, and my source book was reservoir geomechanics for prof Mark Zoback, soon the PDF copy will be available as well.

1. RESERVOIR
GEOMECHANICS
PREPARED BY ASSEM ELBAKLY
SUPERVISED BY. PROF SHADIA TAHA ELKHODARY

2. AGENDA
• Introduction
• Basic concepts
• Measuring stress magnitudes and orientation in the
vertical and deviated wells
• Applications

3. Reservoir Geomechanics is, simply, defined as a branch of science that integrates or combines several sciences
like structural geology, earthquake seismology, tectonic geology, rock mechanics, petroleum engineering,
together for solving several geomechanical problems that arise during the lifetime cycle of a well starting from
exploration to the abundance of the well.

4. 1- INTRODUCTION
• Stress is defined as a force acting over a given area. To conform with common practice in the oil and
gas industry around the world, it is expressed using both English units (psi) and SI units(megapascals
(MPa), where 1 MPa = 145 psi).
• Tensor transformation
• Stress in the earth is compressive
• Anderson classification for Relative stress magnitudes
• Stress magnitudes can be measured at depth using logs and formula

6. • Pore pressure
• Mechanisms of overpressure generation
• Reservoir compartmentalization
• Estimating pore pressure at depth
• Balancing the pore pressure through the life cycle of the well
a must for guaranteeing the safety of the crew on rig

8. 2- BASIC CONCEPTS
• Basic constitutive laws
• Elastic moduli
• Elastic moduli and seismic wave velocity, In an elastic, isotropic, homogeneous solid the elastic
moduli also can be determined from the velocity of compressional waves (Vp) and shear waves (Vs) using the
following relations
• Rock Strength
• Terzaghi form of effective stress and Biot constant

11. 3- MEASURING STRESS MAGNITUDES AND
ORIENTATIONS
• Compressive and tensile failures in vertical wells
• Stress concentration around a cylindrical hole and wellbore failure
• Introduction to breakouts
• Chemical effects
• Wellbore failure and stress determination in deviated wells
• State of stress surrounding an arbitrarily deviated well
• Failure of arbitrarily deviated wells

14. 4- APPLICATIONS
• Wellbore Stability
Wellbore stability problems cost industry between $1- 6 Billion per year world-wide.
• Mechanical instabilities account for the many of these problems
• Instabilities result when the stresses around a well exceed the rock strength(often in the formations above
the reservoir)
• Stable and unstable wells
• During Drilling: Wellbore enlargements due to compressive failure, contribute to hole collapse, excess
cuttings, and hydraulics problems, Excessive mud weight can cause lost circulation problems, increased
exposure times, and formation damage, and add to well costs
• During the Life of the Well:
• • Depletion and drawdown can cause sand production, hole collapse, and casing damage