Regional Fractures I: A Mechanism for the Formation of Regional Fractures at Depth in Flat-Lying Reservoirs (1)

摘要: "Regional" fractures may form slowly, at depth, in extension, and parallel to regional horizontal tectonic compression. Such fracture sets can be common reservoirs despite the absence of flexure strata, are commonly important contributors reservoir permeability. make good targets for deviated wells. High formation pore pressure is crucial creating low effective confining stresses brittle rock properties (conditions conducive fracturing) deep burial, but does not exceed least principal stress cause tensile fracturing: mechanism natural hydraulic fracturing incompatible with characteristics most sets. Rather, many duri g far-field compression, initiate locally induced caused by flaws rock, propagate plane maximum intermediate compressive stresses. The differential required initiation propagation well below that necessary shear failure. In presence high pressure, held open depth a tectonic, basinwide dilatancy void space becomes mineralized.