Page 10 - Reservoir Geomechanics

ix Contents

More on drilling-induced tensile fractures 190
More on wellbore breakouts 196

7 Determination of S 3 from mini-fracs and extended leak-off tests
and constraining the magnitude of S Hmax from wellbore failures
in vertical wells 206

208
Hydraulic fracturing to determine S 3
Can hydraulic fracturing be used to estimate the magnitude of S Hmax ? 220
222
Wellbore failure and the determination of S Hmax
228
Drilling-induced tensile fractures and the magnitude of S Hmax
Estimating rock strength from breakouts when tensile
fractures are present 231
Estimating S Hmax from breakout rotations 231
Summary 233

8 Wellbore failure and stress determination in deviated wells 235

State of stress surrounding an arbitrarily deviated well 236
Failure of arbitrarily deviated wells 239
Confirming that S Hmax and S hmin are principal stresses 246
Estimating S Hmax from breakouts and tensile fractures
in deviated wells 247
Distinguishing drilling-induced tensile fractures
from natural fractures 252
Determination of S Hmax orientation from shear velocity anisotropy
in deviated wells 255

9 Stress fields – from tectonic plates to reservoirs around the world 266

Global stress patterns 266
Sources of crustal stress 270
Normal faulting stress fields in sedimentary basins 273
Methods for approximating S hmin in normal faulting areas 281
Compressional stress states in sedimentary basins 287
Afew more comments about the bilateral constraint 292
Interpolation and extrapolation of stress magnitude data 294