Controls on Convective Fluid Flow Systems Resulting in the Formation of Massive Diagenetic Alterations

Abstract

This contribution presents a series of heat and fluid flow numerical simulations to evaluate the main controls on the activation of convective fluid flow systems that cause massive diagenetic alterations in carbonate basins. The models are based on the Aptian-Albian Benicàssim outcrop analogue, in which large bodies of hydrothermal dolostone replace shallow-marine platform limestones. The results indicate that a convective fluid flow system could only be active if a series of conditions were met. These include a relatively high geothermal gradient, a nearly hydrostatic fluid pressure gradient and high-permeability faults. Moreover, the presence of strong permeability differences among the different limestone units, together with a top seal, favors the formation of stratabound alteration geometries. These factors are in agreement with geological observations and data of the case study.