Application of rock mechanics in hydraulic fracturing theories
Three simplified aspects of rock behavior hae been of value in the study of rock mechanics and hydraulic fracturing theory. First, rocks behave elastically in a broad sense, and for some situations, the linear elastic theory will yield meaningful engineering solutions. Caution should be exercised if a combination of tensile and compressive stress is present. Second, rocks will fail in shear under certain combinations of stresses. This behavior can be described adequately by the simple Mohr concept of shear failure. A third aspect involves the idea of cohesiveness or absorption of surface energy during extension of a hydraulic fracture. Calculations and field evidence indicate that horizontal stresses are generally less than vertical stresses; this condition favors vertical fractures. Attempts to control fracture orientation have led to studies of fracture initiation from well bores, perforations, and notches. Such studies have shown that regardless of initial fracture orientation, upon extension, the fracture tends to become perpendicular to the plane of minimum stress. Fractures can be restricted vertically by zones of high stress. For long fractures, the extension pressure must be consistent with rock surface energy and fluid dynamics considerations. (51 refs.)
- Research Organization:
- Atlantic Richfield Co
- OSTI ID:
- 6036078
- Journal Information:
- 7th World Petr. Congr., Mexico; (United States), Journal Name: 7th World Petr. Congr., Mexico; (United States) Vol. PD-7(8)
- Country of Publication:
- United States
- Language:
- English
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Hydraulic fracture propagation in layered rock: experimental studies of fracture containment
Related Subjects
020300* -- Petroleum-- Drilling & Production
58 GEOSCIENCES
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
COMMINUTION
COMPRESSION STRENGTH
ELASTICITY
FAILURES
FLUID FLOW
FRACTURES
FRACTURING
HYDRAULIC FRACTURING
MECHANICAL PROPERTIES
MECHANICS
OIL WELLS
ORIENTATION
ROCK MECHANICS
SHEAR
STRESSES
TENSILE PROPERTIES
WELLS