... Poroelastic solution Thermoelastic solution Time, sec Cr a ck m a xim u m o pe n in g, m Fig. 5. Maximum crack opening under poro-thermo- mechanical oading 4.3. Stress intensity factor of a crack intersecting with a borehole In order to study the fracture behavior near a borehole, the stress intensity factors...

...). The specimens are then loaded in biaxial compression in such a way that slip propagates from the weak to the strong zone. The slip process can be treated as a mode II crack propagation and the Stress Intensity Factor (KII) is computed by inversion of the stress field observed at the tip of the weak zone...

... breakdown propellant fracture propagation stress intensity factor hydraulic fracturing propellant burning modeling wellbore breakdown fracture initiation pressure buildup wellbore Upstream Oil & Gas stimulation bubble expansion propellant gas fracture pressurisation rate...

... is taking place, the crack starts to open asymmetrically, thus causing an increase of both mode I and mode I1 stress intensity factors. Both K, and K I I can be expressed in term of forces and moment at the crack tips. The stress intensity factors in the post-buckling regime can be calculated using...

... Upstream Oil & Gas Reservoir Characterization stress intensity factor specimen rock material mortar specimen test method determination tensile strength specimen geometry hoop test equation Pacific Rocks 2000, Girard, Liebman, Breeds & Doe (eds) O 2000 Balkema, Rotterdam, ISBN 905809 155 4...

... at the borehole wall that trigger the failure process. Breakdown, in this context, occurs when the stress intensity factor of a critically oriented micro-crack reaches the rock toughness. The model is presently restricted to low-permeability/low-porosity rocks. By considering one-dimensional lubrication flow...

.... Upstream Oil & Gas mechanism lt 2 hydraulic fracturing transverse fracture experiment pressurisation rate fracture Reservoir Characterization stress intensity factor viscosity MPa wellbore perpendicular stress contrast reservoir geomechanics axial fracture fracture geometry borehole...

... strength crack length Artificial Intelligence stress intensity factor probabilistic model brittle material compressive strength hydraulic fracturing fracture mechanics reservoir geomechanics mechanism specimen size probability propagation interaction scale effect specimen crack propagation...

... of all, laboratory compressive strengths are an order of magnitude larger than tensile strengths; secondly, a negative stress intensity factor imposed by far-field compressive stresses acting normal to the crack can arrest compression-driven joints that grow without the aid of a tensile component...