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The [[South Viking Graben]] area, in many respects, shares a broadly similar history in terms of geological evolution with the North Viking Graben, with respect to the overall timing and orientation of Late [[Jurassic]] extension, [[stratigraphy|stratigraphic]] evolution, and [[structure|structural]] styles (Turner and Connell, 1991<ref name=Turnerandconnell1991>Turner, C. C., and E. R. Connell, 1991, Stratigraphic relationships between Upper Jurassic submarine fan sequences in the Brae area, UK North Sea: The implications for reservoir distribution, in Proceedings of the 23rd Annual Offshore Technology Conference: Offshore Technology Conference 6508, Houston, Texas, May 6–9.</ref>; Cherry, 1993<ref name=Cherry1993>Cherry, S. T. J., 1993, The interaction of structure and sedimentary process controlling deposition of the Upper Jurassic Brae Formation Conglomerate, Block 16/17, North Sea, in J. R. Parker, ed., Petroleum geology of NW Europe: Proceedings of the 4th Conference: Geological Society (London), p. 387–400.</ref>; Underhill, 1998<ref name=Underhill1998>Underhill, J. R., 1998, Jurassic, in K. Glennie, ed., Petroleum Geology of the North Sea: Basic Concepts and Recent Advances, 4th ed.: Oxford, Blackwell Science, p. 245–293.</ref>; Fraser et al., 2003<ref name=Fraseretal2003>Fraser, S., A. M. Robinson, H. D. Johnson, J. R. Underhill, D. G. A. Kadolsky, R. Connell, P. Johannessen, and R. Ravnas, 2003, Upper Jurassic, in D. Evans, C. Graham, A. Armour, and P. Bathurst, eds., The Millennium atlas: Petroleum geology of the central and northern North Sea: Geological Society (London), p. 157–189.</ref>). However, because of the presence of Zechstein salt at depth within parts of the South Viking Graben, including the vicinity of the Kingfisher field, the evolution of the [[Brae area]] in particular shows some similarities to parts of the Central Graben where halokinesis has provided a localized control on subsidence and the evolution of [[fault]]ing. This has resulted in a more complex and diverse range of geological structures when compared to the more classical rotated fault blocks of the North Viking Graben Brent province.

The [[South Viking Graben]] area, in many respects, shares a broadly similar history in terms of geological evolution with the North Viking Graben, with respect to the overall timing and orientation of Late [[Jurassic]] extension, [[stratigraphy|stratigraphic]] evolution, and [[structure|structural]] stylesref name=Turnerandconnell1991>Turner, C. C., and E. R. Connell, 1991, Stratigraphic relationships between Upper Jurassic submarine fan sequences in the Brae area, UK North Sea: The implications for reservoir distribution, in Proceedings of the 23rd Annual Offshore Technology Conference: Offshore Technology Conference 6508, Houston, Texas, May 6–9.</ref><ref name=Cherry1993>Cherry, S. T. J., 1993, The interaction of structure and sedimentary process controlling deposition of the Upper Jurassic Brae Formation Conglomerate, Block 16/17, North Sea, in J. R. Parker, ed., Petroleum geology of NW Europe: Proceedings of the 4th Conference: Geological Society (London), p. 387–400.</ref><ref name=Underhill1998>Underhill, J. R., 1998, Jurassic, in K. Glennie, ed., Petroleum Geology of the North Sea: Basic Concepts and Recent Advances, 4th ed.: Oxford, Blackwell Science, p. 245–293.</ref><ref name=Fraseretal2003>Fraser, S., A. M. Robinson, H. D. Johnson, J. R. Underhill, D. G. A. Kadolsky, R. Connell, P. Johannessen, and R. Ravnas, 2003, Upper Jurassic, in D. Evans, C. Graham, A. Armour, and P. Bathurst, eds., The Millennium atlas: Petroleum geology of the central and northern North Sea: Geological Society (London), p. 157–189.</ref>. However, because of the presence of Zechstein salt at depth within parts of the South Viking Graben, including the vicinity of the Kingfisher field, the evolution of the [[Brae area]] in particular shows some similarities to parts of the Central Graben where halokinesis has provided a localized control on subsidence and the evolution of [[fault]]ing. This has resulted in a more complex and diverse range of geological structures when compared to the more classical rotated fault blocks of the North Viking Graben Brent province.

The main period of extensional rifting in the [[South Viking Graben]] occurred during the Late [[Jurassic]] ([[Kimmeridgian]]–[[Tithonian]]) and was predated by comparatively minor extensional episodes during the [[Triassic]] and Middle Jurassic. Evidence based on [[seismic data|seismic]] and well data sets shows that Upper Jurassic [[fault]]s exploited and reactivated some existing Middle Jurassic faults in places. Salt halokinesis and [[subsidence]] also, in part, controlled the location of Upper Jurassic fault systems and, as a result, the development of [[synrift]] [[hanging wall]] [[basin]]s and [[footwall]] highs. In addition, minor compressional phases within the South Viking Graben area during the Early [[Cretaceous]] to [[Cenozoic]] appear to be similar in timing and structural style to events seen in the Central North Sea. The compression resulted in structural inversion and folding of Jurassic and Lower Cretaceous sequences within the immediate hanging walls of major Upper Jurassic faults. The East Brae (Branter, 2003) and North Brae structures show clear evidence for inversion (Stephenson, 1991<ref name=Stephenson1991>Stephenson, M. A., 1991, The North Brae Field, Block 16/7a, UK North Sea, in I. L. Abbotts, ed., United Kingdom oil and gas fields: 25 years commemorative volume: Geological Society (London) Memoir 14, p. 43–48.</ref>; Brehm, 2003<ref name=Brehm2003>Brehm, J. A., 2003, The North Brae and Beinn Fields, Block 16/7a, 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. 199–209.</ref>). However, some of the structures that have previously been interpreted as being compressional in origin might actually have formed, in whole or in part, as a result of extensional [[tectonic]]s. In this alternate scenario, some of the structures expressed at the Base Cretaceous unconformity (BCU) can be envisaged as being related to synrift [[fault]] growth and linkage instead of the result of structural inversion.

The main period of extensional rifting in the [[South Viking Graben]] occurred during the Late [[Jurassic]] ([[Kimmeridgian]]–[[Tithonian]]) and was predated by comparatively minor extensional episodes during the [[Triassic]] and Middle Jurassic. Evidence based on [[seismic data|seismic]] and well data sets shows that Upper Jurassic [[fault]]s exploited and reactivated some existing Middle Jurassic faults in places. Salt halokinesis and [[subsidence]] also, in part, controlled the location of Upper Jurassic fault systems and, as a result, the development of [[synrift]] [[hanging wall]] [[basin]]s and [[footwall]] highs. In addition, minor compressional phases within the South Viking Graben area during the Early [[Cretaceous]] to [[Cenozoic]] appear to be similar in timing and structural style to events seen in the Central North Sea. The compression resulted in structural inversion and folding of Jurassic and Lower Cretaceous sequences within the immediate hanging walls of major Upper Jurassic faults. The East Brae<ref name=Branter2003 /> and North Brae structures show clear evidence for inversion<ref name=Stephenson1991>Stephenson, M. A., 1991, The North Brae Field, Block 16/7a, UK North Sea, in I. L. Abbotts, ed., United Kingdom oil and gas fields: 25 years commemorative volume: Geological Society (London) Memoir 14, p. 43–48.</ref><ref name=Brehm2003>Brehm, J. A., 2003, The North Brae and Beinn Fields, Block 16/7a, 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. 199–209.</ref>). However, some of the structures that have previously been interpreted as being compressional in origin might actually have formed, in whole or in part, as a result of extensional [[tectonic]]s. In this alternate scenario, some of the structures expressed at the Base Cretaceous unconformity (BCU) can be envisaged as being related to synrift [[fault]] growth and linkage instead of the result of structural inversion.

The [[stratigraphy]] of the [[South Viking Graben]] area comprises a [[Permian]]–[[Triassic]] [[prerift]] sequence of mudstones and evaporites overlain by a thin Lower [[Jurassic]] interval and a thicker interval of Middle Jurassic [[Pentland Formation]] and, in some areas, [[Hugin Formation]]. The Pentland Formation contains coal-bearing and mudstone-rich sediments of source rock quality within the oil and gas windows within the area of the Kingfisher field.

The [[stratigraphy]] of the [[South Viking Graben]] area comprises a [[Permian]]–[[Triassic]] [[prerift]] sequence of mudstones and evaporites overlain by a thin Lower [[Jurassic]] interval and a thicker interval of Middle Jurassic [[Pentland Formation]] and, in some areas, [[Hugin Formation]]. The Pentland Formation contains coal-bearing and mudstone-rich sediments of source rock quality within the oil and gas windows within the area of the Kingfisher field.

The Pentland–Hugin Formation interval is overlain by the thick [[Callovian]]–[[Oxfordian]] age [[Heather Formation]], which is dominated by [[claystone]]s inter-bedded with [[limestone]]s and represents the onset of marine conditions within the [[Brae area|Brae subarea]] and wider [[South Viking Graben]] toward the end of the Middle [[Jurassic]] and into the Late Jurassic. A Heather sandstone member is present within the area of the Kingfisher field and is interpreted to represent a deep-marine mass flow [[sandstone]] deposited by turbidity currents. This Heather sand represents a secondary reservoir interval within the Kingfisher field and was developed as a high-pressure and high-temperature (HPHT) [[gas]]-[[condensate]] reservoir (Spence and Kreutz, 2003<ref name=Spenceandkreutz2003 />).

The Pentland–Hugin Formation interval is overlain by the thick [[Callovian]]–[[Oxfordian]] age [[Heather Formation]], which is dominated by [[claystone]]s inter-bedded with [[limestone]]s and represents the onset of marine conditions within the [[Brae area|Brae subarea]] and wider [[South Viking Graben]] toward the end of the Middle [[Jurassic]] and into the Late Jurassic. A Heather sandstone member is present within the area of the Kingfisher field and is interpreted to represent a deep-marine mass flow [[sandstone]] deposited by turbidity currents. This Heather sand represents a secondary reservoir interval within the Kingfisher field and was developed as a high-pressure and high-temperature (HPHT) [[gas]]-[[condensate]] reservoir<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 Grabe]]n area (Spence and Kreutz, 2003<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 />).

[[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. (1993<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: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 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: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 (1991<ref name=Turnerandconnell1991 />) and Spence and Kreutz (2003<ref name=Spenceandkreutz2003 />).]]

[[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 (Rooksby, 1991<ref name=Rooksby1991 />; Garland, 1993<ref name=Garland1993 />; Branter, 2003<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>; Spence and Kreutz, 2003<ref name=Spenceandkreutz2003 />) ([[:file:M115CH10FG01.jpg|Figure 1]], [[:file:M115CH10FG05.jpg|Figure 5]]).

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]]).

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.