Fracture corridors and fault reactivation: Example from the Chalk, Isle of Thanet, Kent, England

Autor: Christine Souque, John C. Lorenz, Philip Jones, Rob J. Knipe, Michael J. Welch, Russell K. Davies
Rok vydání: 2019
Předmět:
Zdroj: Journal of Structural Geology. 122:11-26
ISSN: 0191-8141
Popis: Fracture corridors, elongated zones of narrowly spaced, highly connected, fractures, can generate the main fluid flow pathways in natural reservoirs and can be responsible for an early water break-through in hydrocarbon reservoirs. Understanding this fracturing is necessary for reservoir behaviour prediction. An outcrop analogue of a chalk fractured reservoir from the Isle of Thanet, in SE England is used to understand the development of fracture corridors, and to characterize their relationship with faulting and folding. We show that fracture corridors are associated with strike-slip reactivation on sub-seismic faults in a context of polyphase deformation. They nucleate on slip patch tips or on areas of stress concentration due to fault plane dip/strike irregularities, steps or fault intersections. Fracture corridors generated are oblique to the fault which they initiate on. With increasing deformation, fractures composing the corridor are sheared and a fault can develop within the fracture corridor. The relationship between folding and fracture corridor development in this area is indirect. Both are localized by a pre-existing basement fault that allows stress concentration and reorientation and promotes fault reactivation in the chalk cover. This work emphases the importance of the distribution of sub-seismic faults in fractured reservoirs as they can control the development of fracture corridors.
Databáze: OpenAIRE
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