Changes

Correlation sections that will be used for establishing sandstone body geometry should have a depositionally flat datum (such as a [[bentonit]]e bed, marine shale bed, or laterally persistent limestone). Sections should be oriented parallel and perpendicular to [[depositional strike]], if known, and represent as straight a line as possible given well density and placement.

Correlation sections that will be used for establishing sandstone body geometry should have a depositionally flat datum (such as a [[bentonit]]e bed, marine shale bed, or laterally persistent limestone). Sections should be oriented parallel and perpendicular to [[depositional strike]], if known, and represent as straight a line as possible given well density and placement.

The only sedimentologically significant correlation horizons are those that approximate [[time lines]] within and between sandstone bodies. This style of correlation requires an understanding of the succession of depositional environments and intervening [[Unconformities|unconformable surfaces]]. It often leads to nonparallel and nonhorizontal correlations. For example, in [[Shoreline deposits|shoreface]] systems, time lines denoted by shale or silt breaks between shingled shoreface sheets and lenses are inclined in a seaward ([[depositional dip]]) direction (Figure 2).

The only sedimentologically significant correlation horizons are those that approximate [[time lines]] within and between sandstone bodies. This style of correlation requires an understanding of the succession of depositional environments and intervening [[Unconformities|unconformable surfaces]]. It often leads to nonparallel and nonhorizontal correlations. For example, in [[Lithofacies and environmental analysis of clastic depositional systems#Shoreline deposits|shoreface]] systems, time lines denoted by shale or silt breaks between shingled shoreface sheets and lenses are inclined in a seaward ([[depositional dip]]) direction (Figure 2).

[[file:lithofacies-and-environmental-analysis-of-clastic-depositional-systems_fig2.png|thumb|{{figure number|2}}Gamma ray correlation (dip section) of a series of prograding shoreface sandstones. Note the imbricate nature of the sandstone bodies and the “non-layer cake” nature of the correlations.]]

[[file:lithofacies-and-environmental-analysis-of-clastic-depositional-systems_fig2.png|thumb|{{figure number|2}}Gamma ray correlation (dip section) of a series of prograding shoreface sandstones. Note the imbricate nature of the sandstone bodies and the “non-layer cake” nature of the correlations.]]