Changes

Reservoirs are inherently heterogeneous assemblages of depositional facies and subfacies (for more information, see [[Lithofacies and environmental analysis of clastic depositional systems#Clastic depositional lithofacies and environments|Clastic lithofacies]] and [[Carbonate reservoir models: facies, diagenesis, and flow characterization#Carbonate sediments and environments|Carbonate lithofacies]]), each with characteristic and commonly differing sediment textures, stratification types, and bedding architectures. Variability is compounded by postdepositional alterations of the strata, such as through [[Reservoir quality#compaction|compaction]], [[Reservoir quality#cementation|cementation]], and [[Understanding the geology of a structural play#Reservoir and seal changes|tectonic deformation]]. Geological heterogeneities have been classified in a variety of ways according to their size or scale; the common categories, used here, are ''wellbore, interwell'', and ''fieldwide'' scales of heterogeneity ([[:file:geological-heterogeneities_fig1.png|Figure 1]]).

Reservoirs are inherently heterogeneous assemblages of depositional facies and subfacies (for more information, see [[Lithofacies and environmental analysis of clastic depositional systems#Clastic depositional lithofacies and environments|Clastic lithofacies]] and [[Carbonate reservoir models: facies, diagenesis, and flow characterization#Carbonate sediments and environments|Carbonate lithofacies]]), each with characteristic and commonly differing sediment textures, stratification types, and bedding architectures. Variability is compounded by postdepositional alterations of the strata, such as through [[Reservoir quality#compaction|compaction]], [[Reservoir quality#cementation|cementation]], and [[Understanding the geology of a structural play#Reservoir and seal changes|tectonic deformation]]. Geological heterogeneities have been classified in a variety of ways according to their size or scale; the common categories, used here, are ''wellbore, interwell'', and ''fieldwide'' scales of heterogeneity ([[:file:geological-heterogeneities_fig1.png|Figure 1]]).

Heterogeneities at the wellbore scale affect matrix [[permeability]], distribution of residual oil, directional flow of fluids, potential fluid-rock interactions, and [[Rock-water reaction: formation damage|formation damage]]. Heterogeneities at the interwell scale affect fluid flow patterns, drainage efficiency of the reservoir, and vertical and lateral sweep efficiency of [[Waterflooding|secondary and tertiary recovery projects]]. Heterogeneities at the fieldwide scale determine the in-place hydrocarbon volume, areal distribution, and trend of hydrocarbon production.

Heterogeneities at the wellbore scale affect matrix [[permeability]], distribution of residual oil, directional flow of fluids, potential [[Rock-water reaction|fluid-rock interactions]], and [[Rock-water reaction: formation damage|formation damage]]. Heterogeneities at the interwell scale affect fluid flow patterns, drainage efficiency of the reservoir, and vertical and lateral sweep efficiency of [[Waterflooding|secondary and tertiary recovery projects]]. Heterogeneities at the fieldwide scale determine the in-place hydrocarbon volume, areal distribution, and trend of hydrocarbon production.

==Wellbore scale heterogeneities==

==Wellbore scale heterogeneities==