Abstract
The salt-floored basin concept as applied to the Louisiana offshore, with its total dependence on laterally migrating salt, provides a dynamic view of geologic evolution. Salt domes, ridges, and massifs move basinward at rates of one to ten cm/yr, causing extensive fracturing, thermal anomalies, and under- and over-pressured horizons. The ever-enlarging sedimentary wedge contains its own tectonics; principally basin-spanning shelf-edge growth faults that sole out in shale layers. Advancing salt tongues can create counter-regional and local growth faults that terminate in the semi-plastic salt. Additional stresses, some by basement faulting, are also active within the salt-floored passive margin.
A geologically reasonable conclusion, derived from the abundance of tectonics, is that the sediments may be thought of as shattered. Porous flowage would be reminiscent of that through a colander, not a sieve. Given the possibility of such massive shattering, it is obligatory to prepare a different paradigm relative to hydrocarbon migration. The now decades old notion that most, if not all, hydrocarbons migrate along regional faults must be modified. The shattered sedimentary wedge becomes a conduit for hydrocarbon migration with some concentration of hydrocarbon flow along regional faults, however intermittent that may be. The sedimentary shattering may be so extensive that a new paradigm need be applied to hydrocarbon migration.
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