Changes

The Heather Formation is in turn overlain by a thick Upper [[Jurassic]] [[synrift]] sequence of interbedded [[claystone]]s and [[sandstone]]s that comprise the Kimmeridge Clay Formation and Brae [[sandstone]] member intervals deposited across the [[South Viking Graben]] area<ref name=Spenceandkreutz2003 />).

The Heather Formation is in turn overlain by a thick Upper [[Jurassic]] [[synrift]] sequence of interbedded [[claystone]]s and [[sandstone]]s that comprise the Kimmeridge Clay Formation and Brae [[sandstone]] member intervals deposited across the [[South Viking Graben]] area<ref name=Spenceandkreutz2003 />).

The Upper [[Jurassic]] Brae [[sandstone]] member can be [[stratigraphy|stratigraphically]] subdivided into a number of sub-intervals or zones based on the recognition and correlation of maximum flooding surface [[shale]]s from biostratigraphy and well log data sets. Based on the Shell stratigraphic scheme, the Brae sandstone member is subdivided into the Brae 1 and Brae 2 zones and each zone can in turn be further subdivided into two discrete sandstone units ([[:file:M115CH10FG04.jpg|Figure 4]]).

The Upper [[Jurassic]] Brae [[sandstone]] member can be [[stratigraphy|stratigraphically]] subdivided into a number of sub-intervals or zones based on the recognition and correlation of maximum flooding surface [[shale]]s from biostratigraphy and well log data sets. Based on the Shell stratigraphic scheme, the Brae sandstone member is subdivided into the Brae 1 and Brae 2 zones and each zone can in turn be further subdivided into two discrete sandstone units ([[:file:M115CH10FG04.jpg|Figure 4]]).

[[file:M115CH10FG04.jpg|300px|thumb|{{figure number|4}}Summary stratigraphic column showing the lithostratigraphic and sequence stratigraphic units and maximum flooding surfaces used to subdivide and correlate within the Brae sandstone member in the area of the Kingfisher field. Also shown are the BP genetic sequences based on Partington et al.<ref name=Partingtonetal1993>Partington, M. A., B. C. Mitchener, N. J. Milton, and A. J. Fraser, 1993, Genetic sequence stratigraphy for the North Sea Late Jurassic and Early Cretaceous: Distribution and prediction of Kimmeridgian–Late Ryazanian reservoirs in the North Sea and adjacent areas, in J. R. Parker, ed., Petroleum geology of Northwest Europe: Proceedings of the 4th Conference: Geological Society (London), p. 347–370.</ref>.]]

The deposition of the Brae [[sandstone]] member represents the influx of large volumes of coarse clastic material into the [[South Viking Graben]] area and [[Brae area|Brae]] subarea during the [[Kimmeridgian]]–[[Tithonian]] [[synrift]] from the Fladen Ground Spur area to the west ([[:file:M115CH10FG03.jpg|Figure 3]], [[:file:M115CH10FG05.jpg|Figure 5]]). During this time, coarse conglomeratic point-sourced [[deep water|deep-water]] fan-apron [[sediment]]s were deposited along the margins of the Fladen Ground Spur forming the proximal Brae fans, which are the reservoir intervals in the South, Central, and North Brae fields as well as the “Trees fields” in Block 16/12 to the south (including Larch, Birch, and Sycamore) and the “T Block” (16/17) fields (Tiffany, Toni, and Thelma). These proximal fan-apron systems were the source of sand-rich turbidity currents that fed finer grained clastic material into the deeper parts of the basin-floor area resulting in the deposition of sand-rich lobe sediments present within the reservoir intervals in the Miller, Kingfisher, and East Brae fields<ref name=Rooksby1991 /><ref name=Garland1993 /><ref name=Branter2003>Branter, S., 2003, The East Brae Field, Blocks 16/03a, 16/03b, 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. 191–197.</ref><ref name=Spenceandkreutz2003 /> ([[:file:M115CH10FG01.jpg|Figure 1]], [[:file:M115CH10FG05.jpg|Figure 5]]).

[[file:M115CH10FG05.jpg|300px|thumb|{{figure number|5}}Simplified schematic map showing the depositional extent of the (A) South Brae and (B) North Brae submarine fan lobes within the Brae depositional system. Note that the South Brae and North Brae submarine fans correspond to the Brae 2 and Brae 1 intervals, respectively. Modified from Turner and Connell<ref name=Turnerandconnell1991 /> and Spence and Kreutz<ref name=Spenceandkreutz2003 />.]]

The deposition of the Brae [[sandstone]] member represents the influx of large volumes of coarse clastic material into the [[South Viking Graben]] area and [[Brae area|Brae]] subarea during the [[Kimmeridgian]]–[[Tithonian]] [[synrift]] from the Fladen Ground Spur area to the west ([[:file:M115CH10FG03.jpg|Figure 3]], [[:file:M115CH10FG05.jpg|Figure 5]]). During this time, coarse conglomeratic point-sourced [[deep water|deep-water]] fan-apron [[sediment]]s were deposited along the margins of the Fladen Ground Spur forming the proximal Brae fans, which are the reservoir intervals in the South, Central, and North Brae fields as well as the “Trees fields” in Block 16/12 to the south (including Larch, Birch, and Sycamore) and the “T Block” (16/17) fields (Tiffany, Toni, and Thelma). These proximal fan-apron systems were the source of sand-rich turbidity currents that fed finer grained clastic material into the deeper parts of the basin-floor area resulting in the deposition of sand-rich lobe sediments present within the reservoir intervals in the Miller, Kingfisher, and East Brae fields<ref name=Rooksby1991 /><ref name=Garland1993 /><ref name=Branter2003>Branter, S., 2003, The East Brae Field, Blocks 16/03a, 16/03b, 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. 191–197.</ref><ref name=Spenceandkreutz2003 /> ([[:file:M115CH10FG01.jpg|Figure 1]], [[:file:M115CH10FG05.jpg|Figure 5]]).

file:M115CH10FG04.jpg|{{figure number|4}}Summary stratigraphic column showing the lithostratigraphic and sequence stratigraphic units and maximum flooding surfaces used to subdivide and correlate within the Brae sandstone member in the area of the Kingfisher field. Also shown are the BP genetic sequences based on Partington et al.<ref name=Partingtonetal1993>Partington, M. A., B. C. Mitchener, N. J. Milton, and A. J. Fraser, 1993, Genetic sequence stratigraphy for the North Sea Late Jurassic and Early Cretaceous: Distribution and prediction of Kimmeridgian–Late Ryazanian reservoirs in the North Sea and adjacent areas, in J. R. Parker, ed., Petroleum geology of Northwest Europe: Proceedings of the 4th Conference: Geological Society (London), p. 347–370.</ref>.]]

file:M115CH10FG05.jpg|{{figure number|5}}Simplified schematic map showing the depositional extent of the (A) South Brae and (B) North Brae submarine fan lobes within the Brae depositional system. Note that the South Brae and North Brae submarine fans correspond to the Brae 2 and Brae 1 intervals, respectively. Modified from Turner and Connell<ref name=Turnerandconnell1991 /> and Spence and Kreutz<ref name=Spenceandkreutz2003 />.

During periods of cessation of deposition of the Brae [[conglomerate]]s and sands along the margins of the Fladen Ground Spur, and more distal parts of the basin to the east and northeast, the deposition of organic-rich hemipelagic [[shale]]s occurred in an overall anoxic basin-floor environment resulting in the deposition of the Kimmeridge Clay Formation, with which the Brae reservoirs interfinger. The Kimmeridge Clay Formation [[source rock]] generated much of the [[hydrocarbon]]s that have accumulated in, and been produced from, the [[Brae area]] fields as well as providing top, base, and lateral [[seal]]s to the hydrocarbon accumulations.

During periods of cessation of deposition of the Brae [[conglomerate]]s and sands along the margins of the Fladen Ground Spur, and more distal parts of the basin to the east and northeast, the deposition of organic-rich hemipelagic [[shale]]s occurred in an overall anoxic basin-floor environment resulting in the deposition of the Kimmeridge Clay Formation, with which the Brae reservoirs interfinger. The Kimmeridge Clay Formation [[source rock]] generated much of the [[hydrocarbon]]s that have accumulated in, and been produced from, the [[Brae area]] fields as well as providing top, base, and lateral [[seal]]s to the hydrocarbon accumulations.