Changes

===Subtidal-supratidal dolomitization and sulfate emplacement reservoir model===

===Subtidal-supratidal dolomitization and sulfate emplacement reservoir model===

The subtidal-supratidal model (Figure 3) is based on the transport of carbonate sediment onto the shore by storm and tidal currents resulting in the progradation of the tidal flat environment over the subtidal environment. Subtidal intervals are commonly composed of mudstones, wackestones, packstones, and grainstones in no predictable order. When present, grain-supported sediments may be concentrated in the upper part of the subtidal section in the form of offshore bars and high energy shoreface deposits. Intertidal and supratidal sediments are typically muddy except in association with high energy subtidal sediments. A typical vertical sequence would show intercalated mud- and grain-supported sediments in the subtidal interval overlain by algal mats in the intertidal interval, and mud-cracked and desiccated wackestones and mudstones in the supratidal interval.

The subtidal-supratidal model ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig3.png|Figure 3]]) is based on the transport of carbonate sediment onto the shore by storm and tidal currents resulting in the progradation of the tidal flat environment over the subtidal environment. Subtidal intervals are commonly composed of mudstones, wackestones, packstones, and grainstones in no predictable order. When present, grain-supported sediments may be concentrated in the upper part of the subtidal section in the form of offshore bars and high energy shoreface deposits. Intertidal and supratidal sediments are typically muddy except in association with high energy subtidal sediments. A typical vertical sequence would show intercalated mud- and grain-supported sediments in the subtidal interval overlain by algal mats in the intertidal interval, and mud-cracked and desiccated wackestones and mudstones in the supratidal interval.

The subtidal-supratidal sequence is commonly dolomitized and contains anhydrite and gypsum. In the subtidal interval, dolomitized grainstones retain their intergranular pore space, except where cemented by anhydrite, and form permeable units. Dolomitization of the subtidal mud-supported sediments converts the tight, mud-supported limestones to permeable units because of the larger dolomite crystals and intercrystalline pore space. This produces two types of flow units in the subtidal interval: a dolomud-supported flow unit and a dolograin-supported flow unit. Each will have a unique porosity-permeability transform.

The subtidal-supratidal sequence is commonly dolomitized and contains anhydrite and gypsum. In the subtidal interval, dolomitized grainstones retain their intergranular pore space, except where cemented by anhydrite, and form permeable units. Dolomitization of the subtidal mud-supported sediments converts the tight, mud-supported limestones to permeable units because of the larger dolomite crystals and intercrystalline pore space. This produces two types of flow units in the subtidal interval: a dolomud-supported flow unit and a dolograin-supported flow unit. Each will have a unique porosity-permeability transform.