This course is designed to provi de an appreciation of the significant differences in the effects on reserv oir permeability of the most common extension and shear fracture types.&nb sp\; Extension fractures typically occur as sets of parallel fractures tha t produce a strong horizontal permeability anisotropy in a reservoir and l imited, strata-bound vertical permeability. \; In contrast, shear frac tures commonly create an interconnected, more isotropic horizontal permeab ility system, with a higher probability of a fracture system that is verti cally-connected across minor bedding contrasts. \; However, some shear fracture types degrade reservoir permeability.
This course explore s the different characteristics of extension and shear fractures so that t hey can be recognized in core and image logs. \; The course also brief ly describes the mechanics of creating fractures in the subsurface in orde r to provide a basis for predicting fracture types in a reservoir. \; The course examines the effects of fractures on a reservoir, including the differences between extension and shear fractures due to their dissimilar orientations relative to the in situ stresses, and it explores the intera ctions between natural fractures and hydraulic stimulation fractures. \;
The course is designed to provide participants with an introduct ory working knowledge of fracture systems and their effects on reservoirs. \; A small set of nine core hand samples illustrating natural shear a nd extension fractures, induced fractures, and coring artifacts will be se t out on a table to demonstrate some of the differences between natural an d induced fractures in core. \;