Advective Heat Transport and the Salt Chimney Effect: A Numerical Analysis

Figure 11

Schematic illustration of the evolution of the thermal and fluid system structure near a passively growing salt diapir. Note that the near-salt stratal architecture is highly simplified and should not be taken to represent specific truncation, pinchout, or folded geometries of seal or reservoir rocks. The diagram also omits any near-salt deformation or mineralization, both of which could locally alter porosity and permeability and, thus, fluid system structure. (a) Early in diapirism, advective heat transport controls the thermal structure of the basin with distinct zones of upwelling warm waters adjacent to the diapir and deeper in the minibasin. (b) During an intermediate stage of diapir evolution, the thermal structure is a result of both advective heat transport and thermal conduction through the salt, producing a combined thermal structure with advective heat transport dominating in the upper reservoir and beginning to wane in the lower reservoir. (c) A mature salt diapir with complex, heterogeneous stratigraphy. The impact of advective heat transport is diminished and only affects sediments adjacent to the salt-sediment interface. Conduction controls the thermal structure in the basal units with advection, and likely thermohaline convection, taking place in the high permeability shallow units. Dense saline brines have stabilized in the deepest reservoir rocks.