Changes

The term ''reservoir heterogeneity'' is used here to describe the geological complexity of a [[What is a reservoir system?|reservoir]] and the relationship of that complexity to the flow of fluids through it.<ref name=pt06r4>Alpay, O. A., 1972, A practical approach to defining reservoir heterogeneity: Journal of Petroleum Technology, 24, p. 841–848., 10., 2118/3608-PA</ref>

The term ''reservoir heterogeneity'' is used here to describe the geological complexity of a [[What is a reservoir system?|reservoir]] and the relationship of that complexity to the flow of fluids through it.<ref name=pt06r4>Alpay, O. A., 1972, A practical approach to defining reservoir heterogeneity: Journal of Petroleum Technology, 24, p. 841–848., 10., 2118/3608-PA</ref>

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 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 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 fluid-rock interactions, and 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.