Changes

==Fieldwide scale heterogeneities==

==Fieldwide scale heterogeneities==

[[file:geological-heterogeneities_fig5.png|thumb|{{figure number|5}}Architectural elements of a barrier island sand body. (From <ref name=pt06r35>Galloway, W. E., Cheng, E. S. S., 1985, Reservoir facies architecture in a microtidal barrier system—Frio Formation, Texas Gulf Coast: The University of Texas Bureau of Economic Geology, Report of Investigations, v. 144, 36 p.</ref>.)]]

[[file:geological-heterogeneities_fig5.png|thumb|300px|{{figure number|5}}Architectural elements of a barrier island sand body. (From <ref name=pt06r35>Galloway, W. E., Cheng, E. S. S., 1985, Reservoir facies architecture in a microtidal barrier system—Frio Formation, Texas Gulf Coast: The University of Texas Bureau of Economic Geology, Report of Investigations, v. 144, 36 p.</ref>.)]]

Elements of fieldwide variability include reservoir thickness, facies geometries and continuity, and bulk [[Petroleum reservoir fluid properties|reservoir properties]]. Like interwell heterogeneity, heterogeneities at this scale are difficult to assess because information derived at smaller scales must be scaled up and generalized. Depositional models, determined by geological description at the smaller scales, provide the main basis for interpreting fieldwide reservoir architecture. (For more on depositional models, see [[Lithofacies and environmental analysis of clastic depositional systems]] and [[Carbonate reservoir models: facies, diagenesis, and flow characterization]].) It is very important to describe the reservoir at this scale adequately because reservoirs, being complex depositional systems, are often compartmentalized ([[:file:geological-heterogeneities_fig5.png|Figure 5]]), and separate compartments may not be in communication (see [[Evaluating stratigraphically complex fields]]).

Elements of fieldwide variability include reservoir thickness, facies geometries and continuity, and bulk [[Petroleum reservoir fluid properties|reservoir properties]]. Like interwell heterogeneity, heterogeneities at this scale are difficult to assess because information derived at smaller scales must be scaled up and generalized. Depositional models, determined by geological description at the smaller scales, provide the main basis for interpreting fieldwide reservoir architecture. (For more on depositional models, see [[Lithofacies and environmental analysis of clastic depositional systems]] and [[Carbonate reservoir models: facies, diagenesis, and flow characterization]].) It is very important to describe the reservoir at this scale adequately because reservoirs, being complex depositional systems, are often compartmentalized ([[:file:geological-heterogeneities_fig5.png|Figure 5]]), and separate compartments may not be in communication (see [[Evaluating stratigraphically complex fields]]).