Changes

All three strata types may be found on dune foresets. By contrast, wind-ripple lamination dominates the interdune sediments. These are typically poorly sorted and finely laminated. Interdune sediments probably create an interleaving network of permeability baffles, which serve to create tortuous flow pathways upward through stacked dune reservoirs ([[:file:M91FG171.JPG|Figure 2c]], [[:file:M91FG172.JPG|Figure 3]]). They can act to inhibit coning in thick dune sandstone reservoirs.<ref name=Weber_1987 />

All three strata types may be found on dune foresets. By contrast, wind-ripple lamination dominates the interdune sediments. These are typically poorly sorted and finely laminated. Interdune sediments probably create an interleaving network of permeability baffles, which serve to create tortuous flow pathways upward through stacked dune reservoirs ([[:file:M91FG171.JPG|Figure 2c]], [[:file:M91FG172.JPG|Figure 3]]). They can act to inhibit coning in thick dune sandstone reservoirs.<ref name=Weber_1987 />

Eolian dune sets show strong lateral permeability anisotropy within the reservoir. Reservoir fluids flowing across the wind-flow direction are impeded by pin-stripe lamination of fine-grained material along the dune cross sets. By contrast, the individual layers and laminae are much more continuous along the depositional strike trend of the dune system, perpendicular to the wind flow direction ([[:file:M91FG171.JPG|Figure 2d]]).<ref name=Weber_1987 /> Krystinik<ref name=Krystinik_1990 /> stated that, in most eolian reservoirs, the anisotropy permeability ratio is between 4:1 and 25:1, although the overall range may be approximately 1: 1 and up to 200:1 locally. He recommends that horizontal core plugs should be taken both along and perpendicular to the wind-flow direction in order to assess the lateral permeability anisotropy in dune sandstones. Follows<ref name=Follows_1997>Follows, E., 1997, [http://pg.geoscienceworld.org/content/3/1/43.short Integration of inclined pilot hole core with horizontal image logs to appraise an eolian reservoir, Auk field, central North Sea]: Petroleum Geoscience, v. 3, p. 43–55.</ref> described how a horizontal well was planned to be drilled along depositional [[dip]] in the Auk oil field in the UK North Sea. The intention was to connect up the highest number of grain-flow sets between bounding laminae so as to maximize production.

Eolian dune sets show strong lateral permeability anisotropy within the reservoir. Reservoir fluids flowing across the wind-flow direction are impeded by pin-stripe lamination of fine-grained material along the dune cross sets. By contrast, the individual layers and laminae are much more continuous along the depositional strike trend of the dune system, perpendicular to the wind flow direction ([[:file:M91FG171.JPG|Figure 2d]]).<ref name=Weber_1987 /> Krystinik<ref name=Krystinik_1990 /> stated that, in most eolian reservoirs, the anisotropy permeability ratio is between 4:1 and 25:1, although the overall range may be approximately 1: 1 and up to 200:1 locally. He recommends that horizontal core plugs should be taken both along and perpendicular to the wind-flow direction in order to assess the lateral permeability anisotropy in dune sandstones. Follows<ref name=Follows_1997>Follows, E., 1997, [http://pg.geoscienceworld.org/content/3/1/43.short Integration of inclined pilot hole core with horizontal image logs to appraise an eolian reservoir, Auk field, central North Sea]: Petroleum Geoscience, v. 3, p. 43–55.</ref> described how a [[horizontal well]] was planned to be drilled along depositional [[dip]] in the Auk oil field in the UK North Sea. The intention was to connect up the highest number of grain-flow sets between bounding laminae so as to maximize production.

==See also==

==See also==