Changes

==Parasequences and parasequence sets==

==Parasequences and parasequence sets==

<gallery mode=packed heights=300px widths=300px>

<gallery mode=packed heights=300px widths=300px>

M91Ch11FG73.JPG|{{figure number|2}}Lithofacies map for the upper Piper Sand interval of the Scott field, UK North Sea (from Guscott et al.<ref>Guscott, S., K. Russell, A. Thickpenny, and R. Poddubiuk, 2003, The Scott field, Blocks 15/21a, 15/22, UK North Sea, in J. G. Gluyas and H. M. Hichens, eds., United Kingdom oil and gas fields, commemorative millennium volume: Geological Society (London) Memoir 20, p. 467–481.</ref>). Reprinted with permission from the Geological Society. See also [[Lithofacies maps]]<ref>Shepherd, M., 2009, [http://archives.datapages.com/data/specpubs/memoir91/CHAPTER11/CHAPTER11.HTM Lithofacies maps], in M. Shepherd, Oil field production geology: [http://store.aapg.org/detail.aspx?id=788 AAPG Memoir 91], p. 93-98.

M91Ch11FG73.JPG|{{figure number|2}}Lithofacies map for the upper Piper Sand interval of the Scott field, UK North Sea (from Guscott et al.<ref name=Guscott>Guscott, S., K. Russell, A. Thickpenny, and R. Poddubiuk, 2003, The Scott field, Blocks 15/21a, 15/22, UK North Sea, in J. G. Gluyas and H. M. Hichens, eds., United Kingdom oil and gas fields, commemorative millennium volume: Geological Society (London) Memoir 20, p. 467–481.</ref>). Reprinted with permission from the Geological Society. See also [[Lithofacies maps]]<ref>Shepherd, M., 2009, [http://archives.datapages.com/data/specpubs/memoir91/CHAPTER11/CHAPTER11.HTM Lithofacies maps], in M. Shepherd, Oil field production geology: [http://store.aapg.org/detail.aspx?id=788 AAPG Memoir 91], p. 93-98.

M91FG102.JPG|{{figure number|3}}Vertical flow barriers can control the drainage patterns in a reservoir. The degree to which individual barriers are effective across the reservoir can be characterized by vertical flow barrier maps.

M91FG102.JPG|{{figure number|3}}Vertical flow barriers can control the drainage patterns in a reservoir. The degree to which individual barriers are effective across the reservoir can be characterized by vertical flow barrier maps.

</gallery>

</gallery>

Shoreface sandstones commonly form parasequence sets (see Chapter 10, this publication). An individual parasequence can comprise a series of facies belts showing a progression from coastal to offshore sediments. For example, in the Scott field in the UK North Sea, back barrier, foreshore, upper shoreface, and lower shoreface facies belts can be mapped out in the Upper Piper Sandstone Member (see [[:File:M91Ch11FG73.JPG|Figure 2]]). (Guscott et al., 2003). An analysis of parasequence stacking patterns can help the geologist to predict and map facies belts in the areas beyond the well control. For example, Spaak et al. (1999) used stacking analysis on the Jurassic shoreface sediments of the Fulmar field, UK North Sea, to help construct the depositional scheme for the reservoir.

Shoreface sandstones commonly form parasequence sets (see Chapter 10, this publication). An individual parasequence can comprise a series of facies belts showing a progression from coastal to offshore sediments. For example, in the Scott field in the UK North Sea, back barrier, foreshore, upper shoreface, and lower shoreface facies belts can be mapped out in the Upper Piper Sandstone Member (see [[:File:M91Ch11FG73.JPG|Figure 2]]).<ref name=Guscott /> An analysis of parasequence stacking patterns can help the geologist to predict and map facies belts in the areas beyond the well control. For example, Spaak et al. (1999) used stacking analysis on the Jurassic shoreface sediments of the Fulmar field, UK North Sea, to help construct the depositional scheme for the reservoir.

The basal section of individual parasequences is defined by a flooding surface that is commonly a marine shale. Shales can isolate individual parasequence shoreface cycles vertically, and they can be laterally extensive for several hundreds of meters or more. Fluid flow communication may occur between parasequences where the shales are absent as a result of erosion or nondeposition. It can be useful to produce vertical flow barrier maps for parasequence boundaries (see [[:File:M91FG102.JPG|Figure 3]]). The localized presence or absence of bounding shales can be a critical feature in the flow geology characterization of a shoreface reservoir (Larue and Legarre, 2004).

The basal section of individual parasequences is defined by a flooding surface that is commonly a marine shale. Shales can isolate individual parasequence shoreface cycles vertically, and they can be laterally extensive for several hundreds of meters or more. Fluid flow communication may occur between parasequences where the shales are absent as a result of erosion or nondeposition. It can be useful to produce vertical flow barrier maps for parasequence boundaries (see [[:File:M91FG102.JPG|Figure 3]]). The localized presence or absence of bounding shales can be a critical feature in the flow geology characterization of a shoreface reservoir (Larue and Legarre, 2004).