--> Abstract: Formation and Dynamics of Overpressured Basin Compartments through Coupling of Diagenetic Reaction-Transport-Mechanical Processes, by E. L. Sonnenthal, J. M. Maxwell, and P. J. Ortoleva; #91012 (1992).

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ABSTRACT: Formation and Dynamics of Overpressured Basin Compartments through Coupling of Diagenetic Reaction-Transport-Mechanical Processes

SONNENTHAL, ERIC L., J. M. MAXWELL, and PETER J. ORTOLEVA, Indiana University, Bloomington, IN

Basin-scale compartments characterized by fluid overpressure, near-planar top seals, internal compartmentation, and abundant hydrocarbons have been well documented. Numerous proposed mechanisms for sealing, overpressure generation, and fluid expulsion exemplify the complexity of compartmentation phenomena and the tight coupling of these processes.

We have developed a coupled reaction-transport-mechanical model that simulates many important aspects of the genesis and dynamics of compartmented basins. The model accounts for pressure solution and mechanical compaction, fracture growth and healing,

fluid flow, heat transport, and sedimentary and tectonic history. Results are given for simulations of two- and three-dimensional systems.

The relative importance of compaction (chemical and mechanical), clay dewatering, and simple organic reactions for fluid overpressuring are evaluated under specific depositional, tectonic subsidence, and thermal histories. The model is used to delineate the styles of compartmentation that can occur in basins of various types (rift, cratonic, and passive margin) and the likely location and quality of seals and reservoirs that can occur. These include the differing effects of vertical faults as a fluid sink or an impermeable boundary. The timing and duration of fracture-mediated episodic fluid release and seeps are shown to be important for the distribution and magnitude of overpressure.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)