Geomechanics Applications in Heavy Oil

Basic Mechanics

• concept of stress/strain

• mechanical properties -Young’s modulus, Poisson’s ratio, bulk modulus, shear modulus, bulk compressibility

• rock strength – UCS, tensile strength and shear strength

• computation of mechanical properties and strength parameters from logs,

• dynamic to static conversion of mechanical properties

Understanding Earth Stresses

• in-situ stresses, plate tectonics

• computing stress profile from logs

• pore pressure and principle of effective stress

• elasticity, plasticity, elasto-plastic, poro-elasticity and poro-elasto-plasticity

• stress measurement and calibration - min-frac/LOT/MDT tests

• basic definitions of fracture gradient and closure pressure and other terminologies used in LOT/XLOT

• how fractures are created, preferential direction, fracture growth – frac height and width

Understanding Rock Failure

• rock failure types and causes - tensile vs shear, failure theories

• description of common rock mechanical core tests

• mechanical properties from core testing

• rock strength parameters from core testing

• Mohr-Coulomb failure envelope and its use geomechanical analysis

Mechanical Earth Modeling (MEM)

• data requirements for a typical geomechanical analysis

• process of building mechanical earth model

• log data - Dipole Sonic Imager (DSI) and Sonic Scanner

• integrating log data, core data and field stress measurements in MEM

• calibration of geomechanical model

Geomechanical effects in SAGD

• geomechanical risk scenarios

• effect of temperature on rock properties, rock strength, porosity and permeability

• thermal stresses/strains, thermal jacking, shear dilation

• effect of injection pressure – alteration in in-situ stresses, variation in horizontal and vertical stresses

• effect of cyclic injection/production (loading/unloading) on rock properties and rock strength

• reservoir compaction, subsidence, and ground uplift

Caprock Integrity Analysis

• Caprock integrity– definitions and expectations of regulatory boards

• assessing hydraulic integrity and mechanical integrity

• effect of dilation on reservoir and caprock

• effect of increased reservoir temperature and pressure on caprock

• caprock failure mechanism - tensile and shear

• fault reactivation

• geomechanics workflow for caprock integrity analysis

Reservoir Geomechanics Coupled Modeling

• what is coupled modeling and what parameters are coupled

• common techniques - one-way and two-way coupling

• advantages and disadvantages of coupled modeling

• overview of software tools available for coupled modeling

• case study examples of caprock integrity analysis using coupled modeling

• Segmental modeling using VISAGE – near-wellbore modeling for wellbore stability analysis

Reservoir Monitoring

• overview of common monitoring techniques

• surface and down hole tools to monitor reservoir and caprock deformation

• how monitoring data are used in geomechanical caprock integrity modeling and prediction of subsidence/compaction in the reservoir