Changes

===Karst-collapse reservoir model===

===Karst-collapse reservoir model===

The karst-collapse model describes a touching vug pore system that is formed by massive dissolution of carbonate resulting from meteoric groundwater flow and subsequent collapse and filling of caverns (Figure 4). This process is independent of the sediment's original environment of deposition. Most karsted carbonates are thought to be related to major dissolution concentrated in the vadose and upper phreatic zones producing a horizontality to the caverns. Cavern geometry is also controlled by fracture orientation, often resulting in caverns with linear trends.

[[file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig4.png|thumb|left|{{figure number|4}}Schematic diagram of the karst-collapse reservoir model showing three karst facies.<ref name=pt06r65>Kerans, C. 1989, Karst-controlled reservoir heterogeneity and an example from the Ellenburger Group (Lower Ordovician) of west Texas: The Univ. of Texas Bureau of Economic Geology Report of Invetigations, n. 186, 40 p.</ref>.]]

[[file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig4.png|thumb|{{figure number|4}}Schematic diagram of the karst-collapse reservoir model showing three karst facies. (From <ref name=pt06r65>Kerans, C. 1989, Karst-controlled reservoir heterogeneity and an example from the Ellenburger Group (Lower Ordovician) of west Texas: The Univ. of Texas Bureau of Economic Geology Report of Invetigations, n. 186, 40 p.</ref>.)]]

The karst-collapse model describes a touching vug pore system that is formed by massive dissolution of carbonate resulting from meteoric groundwater flow and subsequent collapse and filling of caverns ([[:file:carbonate-reservoir-models-facies-diagenesis-and-flow-characterization_fig4.png|Figure 4]]). This process is independent of the sediment's original environment of deposition. Most karsted carbonates are thought to be related to major dissolution concentrated in the vadose and upper phreatic zones producing a horizontality to the caverns. Cavern geometry is also controlled by fracture orientation, often resulting in caverns with linear trends.

Three karst facies can be described that relate to touching vug pore geometries. The roof facies is characterized by dissolution-enhanced fractures formed by cavern collapse. The cave facies is characterized by infill sediment. The floor facies is characterized by collapse breccia from roof collapse and small caverns. Karsted reservoirs are generally highly compartmentalized and very complex.

Three karst facies can be described that relate to touching vug pore geometries. The roof facies is characterized by dissolution-enhanced fractures formed by cavern collapse. The cave facies is characterized by infill sediment. The floor facies is characterized by collapse breccia from roof collapse and small caverns. Karsted reservoirs are generally highly compartmentalized and very complex.