Numerical modelling of the behaviour of the fractured chalk in the Ekofisk reservoir was performed using the distinct element code UDEC-BB. The non-linear fracture behaviour was modelled by the Barton-Bandis model, while the pore collapse of the rock matrix was modelled by NGI's cap plasticity formulation. The analyses were performed to investigate the effects of fractures, both natural and compaction induced on the compaction behaviour of the Ekofisk reservoir, and to determine the shear/normal displacement and permeability coupling of the fractures during pressure depletion and water injection. The results of the modelling could be used as basis for explaining the observed behaviour of the Ekofisk field, provide possible guidelines to future actions in the development of the Ekofisk field, and as input to large-scale models of the Ekofisk field.

Keywords:
effective vertical stress, reservoir characterization, porosity chalk, complex reservoir, boundary, injection, hydraulic fracturing, permeability, pore pressure, chalk
Subjects:
Hydraulic Fracturing, Reservoir Characterization, Unconventional and Complex Reservoirs, Reservoir geomechanics, Naturally-fractured reservoirs
Copyright 1994, Society of Petroleum Engineers
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