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Jurassic and Cretaceous clays of the northern and central North Sea hydrocarbon reservoirs reviewed

Published online by Cambridge University Press:  09 July 2018

M. Wilkinson*
Affiliation:
School of GeoSciences, The University of Edinburgh, Grant Institute, The King's Buildings, West Mains Road, Edinburgh EH9 3JW, UK
R. S. Haszeldine
Affiliation:
School of GeoSciences, The University of Edinburgh, Grant Institute, The King's Buildings, West Mains Road, Edinburgh EH9 3JW, UK
A. E. Fallick
Affiliation:
Scottish Universities Environmental Research Centre, East Kilbride G75 0QF, UK

Abstract

The principal clays of the northern and central North Sea are illite (sometimes with interlayered smectite) and kaolin. Chlorite is only locally important. Although it has been proposed that kaolin within North Sea sandstones is detrital in origin, the majority of workers have concluded that it is authigenic, largely the product of feldspar alteration. Kaolin is found within a wide range of sedimentary settings (and within shales) apparently defying the notion that kaolin is an indicator of meteoric water deposition. Within sandstones, the earliest authigenic kaolin has a vermiform morphology, the distribution of which is controlled by the availability of detrital mica to act as a nucleus, and the composition of the post-depositional porewaters. This vermiform kaolin formed in meteoric water, the presence of which is easily accounted for below sub-aerial exposure surfaces in non-marine formations, and below unconformities over marine units. In fully marine sands, and even marine shale units, kaolin still occurs. It has therefore been suggested that even these locations have been flushed with meteoric water.

Early vermiform kaolin recrystallizes to a more blocky morphology as burial proceeds, at least in the Brent Group. Blocky kaolin has been reported as growing before, synchronously with, and after the formation of quartz overgrowths, though oxygen isotope studies support low-temperature growth, pre-quartz. Blocky kaolin may form during meteoric flushing associated with lower Cretaceous uplift and erosion, though it is found in fault blocks that are thought to have remained below sea level. Here, the kaolin may form in stagnant meteoric water, relics of the post-depositional porewater. It has also been proposed that the blocky kaolin grew in ascending basinal waters charged with carboxylic acids and CO2, though this hypothesis is not supported by stable oxygen isotope data. Some of the blocky kaolin is dickite, the stable polymorph above ∼100°C.

Fibrous illite occurs almost ubiquitously within the clastic sediments of the North Sea. An early pore-lining phase has been interpreted as both infiltrated clastic clay, and as an early diagenetic phase. Early clays may have been quite smectite-rich illites, or even discrete smectites. Later, fibrous illite is undoubtedly neoformed, and can degrade reservoir quality significantly. Both within sandstones and shales, there is an apparent increase in the K content deeper than 4 km of burial, which could be due to dilution of the early smectite-rich phase by new growth illite, or to the progressive illitization of existing I-S. Much of the ‘illite’ that has been dated by the K-Ar method may therefore actually be I-S.

The factors that control the formation of fibrous illite are only poorly known, though temperature must play a role. Illite growth has been proposed for almost the entire range of diagenetic temperatures (e.g. 15–20°C, Brent Group; 35–40°C, Oxfordian Sand, Inner Moray Firth; 50–90°C, Brae formation; 100–110°C, Brent Group; 130–140°C, Haltenbanken). It seems unlikely that there is a threshold temperature below which illite growth is impossible (or too slow to be significant), though this is a recurring hypothesis in the literature. Instead, illite growth seems to be an event, commonly triggered by oil emplacement or another change in the physiochemical conditions within the sandstone, such as an episode of overpressure release. Hence fibrous illite can grow at any temperature encountered during diagenesis.

Although there is an extensive dataset of K-Ar ages of authigenic illites from the Jurassic of the North Sea, there is no consensus as to whether the data are meaningful, or whether the purified illite samples prepared for analysis are so contaminated with detrital phases as to render the age data meaningless. At present it is unclear about how to resolve this problem, though there is some indication that chemical micro-analysis could help. It is a common belief that illite ages record the timing of oil charge, and so can be used to calibrate basin models.

Grain-coating Fe-rich chlorite cements can preserve exceptional porosity during burial. They are found in marginal marine sandstones, formed during diagenesis from precursor Fe-rich clays such as berthierine or verdine.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2006

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References

Barclay, S.A. & Worden, R.H. (2000) Geochemical modelling of diagenetic reactions in a sub-arkosic sandstone. Clay Minerals, 35, 57–67.Google Scholar
Beaufort, D., Cassagnabere, A., Petit, S., Lanson, B., Berger, G., Lacharpagne, J.C. & Johansen, H. (1998) Kaolinite-to-dickite reaction in sandstone reservoirs. Clay Minerals, 33, 297–316.Google Scholar
Bjørkum, P.A. & Gjelsvik, N. (1988) An isochemical model for formation of authigenic kaolinite, K-feldspar and illite in sediments. Journal of Sedimentary Petrology, 58, 506–511.Google Scholar
Bjørkum, P.A., Mjos, R., Walderhaug, O. & Hurst, A. (1990) The role of the late Cimmerian unconformity for the distribution of kaolinite in the Gullfaks field, northern North Sea. Sedimentology, 37, 395–406.Google Scholar
Bjørlykke, K. & Brendsall, A. (1986) Diagenesis of the Brent Group in the Statfjord Field. Pp. 157–168 in: Roles of Organic Matter in Sedimentary Diagenesis (Gaultier, D.L., editor). SEPM Special Publication, 38. SEPM, Tulsa, Oklahoma.Google Scholar
Bjørlykke, K., Nedkvitne, T., Ramm, M. & Saigal, G.C. (1992) Diagenetic processes in the Brent Group (Middle Jurassic) reservoirs, of the North Sea: an overview. Pp. 263–287 in: Geology of the Brent Group (Morton, A.C., Haszeldine, R.S., Giles, M.R. & Brown, S., editors). Special Publication 61. Geological Society, London.Google Scholar
Blackbourn, G.A. (1984) Diagenetic history and reservoir quality of a Brent sand sequence. Clay Minerals, 19, 377–390.Google Scholar
Blanche, J.B. & Whitaker, J.H.McD. (1978) Diagenesis of part of the Brent Sand Formation (Middle Jurassic) of the northern North Sea Basin. Journal of the Geological Society of London, 135, 73–82.Google Scholar
Brint, J.F. (1989) Isotope diagenesis and paleofluid movement: Middle Jurassic Brent sandstones, North Sea. Unpublished PhD thesis, University of Strathclyde, UK.Google Scholar
Burley, S.D. (1986) The development and destruction of porosity within Upper Jurassic reservoir sandstones of the Piper and Tartan fields, Outer Moray Firth, North Sea. Clay Minerals, 21, 649–694.Google Scholar
Burley, S.D. & Flisch, M. (1989) K-Ar geochronology and the timing of detrital I/S clay illitization and authigenic illite precipitation in the Piper and Tartan Fields, Outer Moray Firth, UK North Sea. Clay Minerals, 24, 285–315.Google Scholar
Cavanagh, A.J. (2002) Oil and water-fibrous illite diagenesis and the onset of hydrocarbon charge in the petroleum systems of the Northern North Sea. Unpublished PhD thesis, University of Edinburgh, UK.Google Scholar
Chuhan, F.A., Bjørlykke, K. & Lowrey, C. (2000) The role of provenance in illitization of deeply buried reservoir sandstones from Haltenbanken and north Viking Graben, offshore Norway. Marine and Petroleum Geology, 17, 673–689.Google Scholar
Chuhan, F.A., Bjorlykke, K. & Lowrey, C.J. (2001) Closed-system burial diagenesis in reservoir sandstones: Examples from the Garn Formation at Haltenbanken area, offshore mid-Norway. Journal of Sedimentary Research, 71, 15–26.CrossRefGoogle Scholar
Clauer, N. & Chaudhuri, S. (1995) Clays in Crustal Environments, Isotope Dating and Tracing. Springer Verlag Telos, Germany.Google Scholar
Darby, D., Wilkinson, M., Haszeldine, R.S. & Fallick, A.E. (1997) Illite dates record deep fluid movements in petroleum basins. Petroleum Geoscience, 3, 133–140.Google Scholar
De'Ath, N.G. & Schuyleman, S.F. (1981) The geology of the Magnus oilfield. Pp. 342–351 in: Petroleum Geology of the Continental Shelf of North-West Europe (Illing, L.V. & Hobson, G.D., editors). Institute of Petroleum, Heyden, London.Google Scholar
Deer, W.A., Howie, R.A. & Zussman, J. (1962) Rock-forming Minerals, Volume 3, Sheet Silicates. Longman, Essex, UK.Google Scholar
Drits, V.A., Sakharov, B.A., Lindgreen, H. & Salyn, A. (1997) Sequential structure transformation of illite-smectite-vermiculite during diagenesis of Upper Jurassic shales from the North Sea and Denmark. Clay Minerals, 32, 351–371.Google Scholar
Drits, V.A., Lindgreen, H., Sakharov, B.A., Jakobsen, H.J., Salyn, A.L. & Dainyak, L.G. (2002) Tobelitization of smectite during oil generation in oil-source shales. Application to North Sea illite-tobelite-smectite-vermiculite. Clays and Clay Minerals, 50, 82–98.Google Scholar
Durand, C., Matthews, J.C., Gle allo, Y., Brosse, E. & Sommer, F. (2000) Illitization and silicification in Greater Alwyn: I. Assessing and synthesizing experimental data. Clay Minerals, 35, 211–225.CrossRefGoogle Scholar
Dypvik, H. (1983) Clay mineral transformations in Tertiary and Mesozoic sediments from North Sea. American Association of Petroleum Geologists Bulletin, 67, 160–165.Google Scholar
Eberl, D. & Hower, J. (1976) Kinetics of illite formation. Geological Society of America Bulletin, 87, 1326–1330.Google Scholar
Egeberg, P.K. & Aagaard, P. (1989) Origins and evolution of formation waters from oil fields on the Norwegian Shelf. Applied Geochemistry, 4, 131–142.CrossRefGoogle Scholar
Ehrenberg, S.N. (1991) Kaolinized, K-leached zones at the contacts of the Garn Formation, Haltenbanken, mid-Norwegian continental shelf. Marine and Petroleum Geology, 8, 250–269.Google Scholar
Ehrenberg, S.N. (1993) Preservation of anomalously high-porosity in deeply buried sandstones by grain-coating chlorite – examples from the Norwegian Continental Shelf. American Association of Petroleum Geologists Bulletin, 77, 12601286.Google Scholar
Ehrenberg, S.N. & Nadeau, P.H. (1989) Formation of diagenetic illite in sandstones of the Garn Formation, Haltenbanken area, mid-Norwegian continental shelf. Clay Minerals, 24, 233–253.CrossRefGoogle Scholar
Ehrenberg, S.N., Aagaard, P., Wilson, M.J., Fraser, A.R. & Duthie, D.M.L. (1993) Depth-dependent transformation of kaolinite to dickite in sandstones of the Norwegian Continental Shelf. Clay Minerals, 28, 325–352.CrossRefGoogle Scholar
Ehrenberg, S.N., Dalland, A., Nadeau, P.H., Mearns, E.W. & Amundsen, H.E.F. (1998) Origin of chlorite enrichment and neodymium isotopic anomalies in Haltenbanken sandstones. Marine and Petroleum Geology, 15, 403–425.Google Scholar
Emery, D. & Robinson, A. (1993) Inorganic Geochemistry: Applications to Petroleum Geology. Blackwell Scientific Publications, London.Google Scholar
Emery, D., Smalley, P.C. & Oxtoby, N.H. (1993) Synchronous oil migration and cementation demonstrated by a description of diagenesis. Philosophical Transactions of the Royal Society A, 334, 115–125.Google Scholar
Fairbridge, R.W. (1967) Phases of diagenesis and authigeneis. Pp. 551 in: Diagenesis in Sediments (Larsen, G. & Chilingar, G.V., editors). Developments in Sedimentology, 8. Elsevier, Amsterdam.Google Scholar
Fallick, A.E., Macaulay, C.I. & Haszeldine, R.S. (1993) Implications of linearly correlated oxygen and hydrogen isotopic compositions for kaolinite and illite in the Magnus Sandstone, North Sea. Clays and Clay Minerals, 41, 184–190.Google Scholar
Faure, G. (1986) Principals of Isotope Geology. 2nd edition. John Wiley and Sons, New York.Google Scholar
Giles, M.R. & de Boer, R.B. (1990) Origin and significance of redistributional secondary porosity. Marine and Petroleum Geology, 7, 378–397.Google Scholar
Giles, M.R., Stevenson, S., Martin, S.V., Cannon, S.J.C., Hamilton, P.J., Marshall, J.D. & Samways, G.M. (1992) The reservoir properties and diagenesis of the Brent Group: a regional perspective. Pp. 289–327 in: Geology of the Brent Group (Morton, A.C., Haszeldine, R.S., Giles, M.R. & Brown, S., editors). Special Publication, 61. Geological Society London.Google Scholar
Girard, J.P., Munz, I.A., Johansen, H., Lacharpagne, J.C. & Sommer, F. (2002) Diagenesis of the Hild Brent sandstones, northern North Sea: isotopic evidence for the prevailing influence of deep basinal water. Journal of Sedimentary Research, 72, 746–759.Google Scholar
Glasmann, J.R. (1992) The fate of feldspars in Brent Group Reservoirs, North Sea: a regional synthesis of diagenesis in shallow, intermediate and deep burial environments. Pp. 329–350 in: Geology of the Brent Group (Morton, A.C., Haszeldine, R.S., Giles, M.R. & Brown, S., editors). Special Publication, 61. Geological Society of London.Google Scholar
Glasmann, J.R., Clark, R.A., Larter, S., Briedis, N.A. & Lundegard, P.D. (1989a) Diagenesis and hydrocarbon accumulation, Brent Sandstone (Jurassic), Bergen High area, North Sea. American Association of Petroleum Geologists Bulletin, 73, 1341–1360.Google Scholar
Glasmann, J.R., Larter, S., Briedis, N.A. & Lundegard, P.D. (1989b) Shale diagenesis in the Bergen High area, North Sea. Clays and Clay Minerals, 37, 97–112.Google Scholar
Glasmann, J.R., Lundegard, P.D., Clark, R.A., Penny, B.K. & Collins, I.D. (1989c) Geochemical evidence for the history of diagenesis and fluid migration: Brent Sandstone, Heather Field, North Sea. Clay Minerals, 24, 255–284.Google Scholar
Greenwood, P.J., Shaw, H.F. & Fallick, A.E. (1994) Petrographic and isotopic evidence for diagenetic processes in Middle Jurassic sandstones and mu-drocks from the Brae area, North Sea. Clay Minerals, 29, 637–650.Google Scholar
Hamilton, P.J., Kelley, S. & Fallick, A.E. (1989) K-Ar dating of illite in hydrocarbon reservoirs. Clay Minerals, 24, 215–232.Google Scholar
Hamilton, P.J., Giles, M.R. & Ainsworth, P. (1992) K-Ar dating of illites in Brent Group reservoirs: a regional perspective. Pp. 377–400 in: Geology of the Brent Group (Morton, A.C., Haszeldine, R.S., Giles, M.R. & Brown, S., editors). Special Publication, 61. Geological Society of London.Google Scholar
Hancock, N.J. & Taylor, A.M. (1978) Clay mineral diagenesis and oil migration in the Middle Jurassic Brent Sand Formation. Journal of the Geological Society of London, 135, 69–72.Google Scholar
Hansen, P.L. & Lindgreen, H. (1989) Mixed-layer illite/ smectite diagenesis in Upper Jurassic claystones from the North Sea and onshore Denmark. Clay Minerals, 24, 197–213.Google Scholar
Harris, N.B. (1992) Burial diagenesis of Brent sandstones: a study of Statfjord, Hutton and Lyell fields. Pp. 351–375 in: Geology of the Brent Group (Morton, A.C., Haszeldine, R.S., Giles, M.R. & Brown, S., editors). Special Publication, 61. Geological Society of London.Google Scholar
Hassouta, L. (1999) La comparison de gre`s cimentés et de gre`s non cimentés par la calcite du groupe du Brent (Zone d'alwyn, Mer du Nord). Une clé pour l'establissement de bilans de matie`re et la compré-hension des processus de formation du quartz et des argilles (illite, kaolinite, dickite). PhD thesis, L'Université des Sciences et Technologies de Lille, France.Google Scholar
Hassouta, L., Buatier, M.D., Potdevin, J.L. & Liewig, N. (1999) Clay diagenesis in the sandstone reservoir of the Ellon Field (Alwyn, North Sea). Clay Minerals, 47, 269–285.Google Scholar
Haszeldine, R.S., Brint, J.F., Fallick, A.E., Hamilton, P.J. & Brown, S. (1992) Open and restricted hydrologies in Brent Group diagenesis: North Sea. Pp. 401–419 in: Geology of the Brent Group (Morton, A.C., Haszeldine, R.S., Giles, M.R. & Brown, S., editors). Special Publication, 61. Geological Society of London.Google Scholar
Haszeldine, R.S., Wilkinson, M., Derby, D., Macaulay, C.I., Couples, G.C., Fallick, A.E., Fleming, C.G., Stewart, R.N.T. & McAulay, G. (1999) Diagenetic porosity creation in an overpressured graben. Pp. 1339–1350 in: Petroleum Geology of NW Europe (Boldy, S. & Fleet, S., editors). Geological Society of London.Google Scholar
Heavyside, J., Langley, G.O., & Pallatt, N. (1983) Permeability characteristics of Magnus reservoir rock. 8th SPWLA London Chapter European Formation Evaluation Symposium Transactions, London, March, 1983, Paper A.Google Scholar
Hendry, J.P. & Trewin, N.H. (1995) Authigenic quartz microfabrics in Cretaceous turbidites – evidence for silica transformation processes in sandstones. Journal of Sedimentary Research, A65, 380–392.Google Scholar
Hendry, J.P., Wilkinson, M., Fallick, A.E. & Trewin, N.H. (2000) Disseminated 'jigsaw-piece' dolomite in Upper Jurassic shelf sandstones, Central North Sea: an example of cement growth during bioturbation? Sedimentology, 47, 631–644.Google Scholar
Hillier, S. (1994) Pore-lining chlorites in siliciclastic reservoir sandstones – electron-microprobe, SEM and XRD data, and implications for their origin. Clay Minerals, 29, 665–679.CrossRefGoogle Scholar
Hogg, A.J.C. (1989) Petrographic and isotopic constraints on the diagenesis and reservoir properties of the Brent Group sandstones. PhD thesis, University of Aberdeen, UK.Google Scholar
Hogg, A.J.C., Pearson, M.J., Fallick, A.E., Hamilton, P.J. & Macintyre, R. (1987) Clay mineral and isotope evidence for control on reservoir properties of Brent Group sandstones, British North Sea. Terra Incognita, 7, 342.Google Scholar
Hogg, A.J.C., Hamilton, P.J. & Macintyre, R.M. (1993) Mapping diagenetic fluid flow within a reservoir: K-Ar dating in the Alwyn area (UK North Sea). Marine Petroleum Geology, 10, 279–294.Google Scholar
Hogg, A.J.C., Pearson, M.J., Fallick, A.E. & Hamilton, P.J. (1995) An integrated thermal and isotopic study of the diagenesis of the Brent Group, Alwyn South, UK North Sea. Applied Geochemistry, 10, 531–546.Google Scholar
Hower, J., Eslinger, E.V., Hower, M.E. & Perry, E.A. (1976) Mechanism of burial metamorphism of argillaceous sediment: 1. Mineralogical and chemical evidence. Geological Society of America Bulletin, 87, 725–737.Google Scholar
Huang, W.L., Bishop, A.M. & Brown, R.W. (1986) The effect of fluid/rock ratio on feldspar dissolution and illite formation under reservoir conditions. Clay Minerals, 21, 585–601.Google Scholar
Hurst, A. & Irwin, H. (1982) Geological modelling of clay diagenesis in sandstones. Clay Minerals, 17, 5–22.CrossRefGoogle Scholar
Jahren, J.S. & Aagaard, P. (1989) Compositional variations in diagenetic chlorites and illites, and relationships with porewater chemistry. Clay Minerals, 24, 157–170.Google Scholar
Jeans, C.V. & Atherton, A.F. (1989) Silicate and associated cements in an Oxfordian marine-freshwater transition, Inner Moray Firth, UK North Sea. Clay Minerals, 24, 317–339.Google Scholar
Jeans, C.V. & Fisher, M.J. (1986) Diagenesis in Upper Jurassic marine sandstones from the North Sea well 14/26-1 and its significance. Clay Minerals, 21, 513–535.Google Scholar
Jeremiah, J.M. & Nicholson, P.H. (1999) Middle Oxfordian to Volgian sequence stratigraphy of the Greater Shearwater area. Pp. 153–170 in: Petroleum Geology of Northwestern Europe: Proceedings of the 5th Conference (Fleet, A.J. & Boldy, S.A.R., editors). Geological Society, London.Google Scholar
Jones, T.G.J., Hughes, T.L. & Tomkins, P. (1989) The ion content and mineralogy of a North Sea Cretaceous shale formation. Clay Minerals, 24, 393–410.Google Scholar
Jourdan, A., Thomas, M., Brevart, O., Robson, P., Sommer, F. & Sullivan, M. (1987) Diagenesis as the control of the Brent sandstone reservoir in the Greater Alwyn area (East Shetland Basin). Pp. 951–961 in: Petroleum Geology of N.W. Europe (Brooks, J. & Glennie, K.W., editors). Graham & Trotman, London.Google Scholar
Kantorowicz, J. (1984) The nature, origin and distribution of authigenic Clay Minerals, from Middle Jurassic Ravenscar and Brent Group sandstones. Clay Minerals, 19, 359–375.Google Scholar
Kantorowicz, J.D. (1990) The influence of variations in illite morphology on the permeability of Middle Jurassic Brent Group sandstones, Cormorant Field, UK North-Sea. Marine Petroleum Geology, 7, 66–74.Google Scholar
Land, L.S. (1983) The application of stable isotopes to studies of the origin of dolomite and to problems of diagenesis of clastic sediments. Pp. 4.1–4.22 in: Stable Isotopes in Sedimentary Geology (Arthur, M.A., editor). SEPM Short Course 10, SEPM, Tulsa, Oklahoma.Google Scholar
Land, L.S. & Dutton, S.P. (1978) Cementation of a Pennsylvanian deltaic sandstone: isotopic data. Journal of Sedimentary Petrology, 48, 1167–1176.Google Scholar
Le Gallo, Y., Bildstein, O. & Brosse, E. (1998) Coupled reaction-flow modeling of diagenetic changes in reservoir permeability, porosity and mineral compositions. Journal of Hydrology, 209, 366–388.Google Scholar
Liewig, N., Clauer, N. & Sommer, F. (1987) Rb-Sr and K-Ar dating of clay diagenesis in a Jurassic sandstone reservoir. Bulletin of the American Association of Petroleum Geologists, 71, 1467–1474.Google Scholar
Lindgreen, H. (1994) Ammonium fixation during illite-smectite diagenesis in upper Jurassic shale, North Sea. Clay Minerals, 29, 527–537.Google Scholar
Lindgreen, H., Drits, V.A., Sakharov, B.A., Jakobsen, H.J., Salyn, A.L., Dainyak, L.G. & Kroyer, H. (2002) The structure and diagenetic transformation of illite-smectite and chlorite-smectite from North Sea Cretaceous-Tertiary chalk. Clay Minerals, 37, 429–450.Google Scholar
Lindgreen, H., Jacobsen, H. & Jakobsen, H.J. (1991) Diagenetic structural transformations in North Sea Jurassic illite/smectite. Clays and Clay Minerals, 39, 54–69.Google Scholar
Lindgreen, H., Garnaes, J., Besenbacher, F., Laegsgaard, E. & Stensgaard, I. (1992) IIllite-smectite from the North-Sea investigated by scanning tunnelling microscopy. Clay Minerals, 27, 331–342.Google Scholar
Lønøy, A., Akselsen, J. & Rønning, K. (1986) Diagenesis of a deeply buried sandstone reservoir: Hild Field, Northern North Sea. Clay Minerals, 21, 497–512.Google Scholar
Macaulay, C.I. (1990) Clastic diagenesis and porefluid evolution: an isotopic study, Magnus Oilfield, North Sea. Unpublished PhD thesis, University of Strathclyde, UK.Google Scholar
Macaulay, C.I., Haszeldine, R.S. & Fallick, A.E. (1992) Diagenetic pore waters stratified for at least 35 million years: Magnus oil field, North Sea. Bulletin of the American Association of Petroleum Geologists, 76, 1625–1634.Google Scholar
Maliva, R.G., Dickson, J.A.D. & Fallick, A.E. (1999) Kaolin cements in limestones: potential indicators of organic-rich porewaters during diagenesis. Journal of Sedimentary Research, 69, 158–163.CrossRefGoogle Scholar
Matthews, J.C., Velde, B. & Johansen, H. (1994) Significance of K-Ar ages of authigenic illitic clay-minerals in sandstones and shales from the North Sea. Clay Minerals, 29, 379–389.Google Scholar
McAulay, G.E., Burley, S.D. & Johnes, L.H. (1993) Silicate mineral authigenesis in the Hutton and NW Hutton fields: implications for sub-surface porosity development. Pp. 1377–1394 in: Petroleum Geology of Northwest Europe: Proceedings of the 4th Conference (Parker, J.R., editor). Geological Society, London.Google Scholar
McAulay, G.E., Burley, S.D., Fallick, A.E. & Kusznir, N.J. (1994) Paleohydrodynamic fluid flow regimes during diagenesis of the Brent Group in the Hutton-Northwest Hutton reservoirs: constraints from oxygen isotope studies of authigenic kaolin and reverse flexural modelling. Clay Minerals, 29, 609–626.Google Scholar
McBride, J.J. (1992) The diagenesis of middle Jurassic reservoir sandstones of Bruce Field, UK, North Sea. Unpublished PhD thesis, University of Aberdeen, UK.Google Scholar
McHardy, W.J., Wilson, M.J. & Tait, J.M. (1982) Electron microscope and X-ray diffraction studies of filamentous illitic clay from sandstones of the Magnus Field. Clay Minerals, 17, 23–29.Google Scholar
McLaughlin, Ó.M. (1992) Isotopic and textural evidencé for diagenetic O fluid mixing in the South Brae oilfield, North Sea. Unpublished PhD thesis, University of Glasgow, UK.Google Scholar
McLaughlin, Ó.M., Haszeldine, R.S., Fallick, A.E. & ´ Rogers, G. O. (1994) The case of the missing clay, aluminium loss and secondary porosity, South Brae Oilfield, North Sea. Clay Minerals, 29, 651–664.Google Scholar
Midtbø, R.E.A., Rykkje, J.M. & Ramm, M. (2000) Deep burial diagenesis and reservoir quality along the eastern flank of the Viking Graben. Evidence for illitisation and quartz cementation after hydrocarbon emplacement. Clay Minerals, 35, 227–237.CrossRefGoogle Scholar
Nadeau, P.H. (1985) The physical dimensions of fundamental clay particles. Clay Minerals, 20, 499–514.Google Scholar
Nadeau, P.H., Wilson, M.J., McHardy, W.J. & Tait, J.M. (1994) Interstatified clays as fundamental particles. Science, 225, 923–925.Google Scholar
Newman, A.C.D. & Brown, G. (1987) The chemical constitution of clays. Pp. 1–128 in: Chemistry of Clays and Clay Minerals (Newman, A.C.D., editor). Mineralogical Society, London.Google Scholar
Osborne, M., Haszeldine, R.S. & Fallick, A.E. (1994) Variation in kaolin morphology with growth temperature in isotopically mixed pore-fluids, Brent Group, UK North Sea. Clay Minerals, 29, 591–608.Google Scholar
Pearson, M.J. & Small, J.S. (1988) Illite-smectite diagenesis and palaeotemperatures in northern North Sea Quaternary to Mesozoic shale sequences. Clay Minerals, 23, 109–132.Google Scholar
Pearson, M.J., Watkins, D. & Small, J.S. (1982) Clay diagenesis and organic maturation in Northern North Sea Sediments. Pp. 665–675 in: Proceedings of the International Clay Conference, Pavia & Bologna (Van Olphen, H. & Veniale, F., editors). Developments in Sedimentology, 35. Elsevier, Amsterdam.Google Scholar
Pearson, M.J., Watkins, D., Pittion, J.-L., Caston, D. & Small, J.S. (1983) Aspects of burial diagenesis, organic maturation and palaeothermal history of an area in the South Viking Graben, North Sea. Pp. 161–173 in: Petroleum Geochemistry and Exploration of Europe (Brooks, J., editor). Special Publication, 12, Geological Society, London.Google Scholar
Purvis, K. (1995) Diagenesis of Lower Jurassic sandstones, block-211/13 (Penguin area), UK northern North Sea. Marine Petroleum Geology, 12, 219–228.Google Scholar
Rainey, S.C.R. (1987) Sedimentology, diagenesis and geochemistry of the Magnus Sandstone Member, Northern North Sea. Unpublished PhD thesis, University of Edinburgh, UK.Google Scholar
Ramm, M. & Ryseth, A.E. (1996) Reservoir quality and burial diagenesis in the Statfjord Formation, North Sea. Petroleum Geoscience, 2, 313–324.CrossRefGoogle Scholar
Scotchman, I.C., Johnes, L.H. & Miller, R.S. (1989) Clay diagenesis and oil migration in Brent Group sandstones of NW Hutton Field, UK North Sea. Clay Minerals, 24, 339–374.Google Scholar
Shaw, H.F. & Primmer, T.J. (1991) Diagenesis of mudrocks from the Kimmeridge Clay Formation of the Brae Area, UK North Sea. Marine and Petroleum Geology, 8, 270–277.Google Scholar
Small, J.S., Hamilton, D.L. & Habesch, S. (1992) Experimental simulation of clay precipitation within reservoir sandstones. 2: Mechanism of illite formation and controls on morphology. Journal of Sedimentary Petrology, 62, 520–529.CrossRefGoogle Scholar
Sommer, F. (1978) Diagenesis of Jurassic sandstones in the Central Graben. Journal of the Geological Society of London, 135, 63–67.CrossRefGoogle Scholar
Spark, I.S.C. & Trewin, N.H. (1986) Facies-related diagenesis in the Main Claymore Oilfield sandstones. Clay Minerals, 21, 479–496.Google Scholar
Stewart, D.J. (1986) Diagenesis of the shallow marine Fulmar Formation in the Central North Sea. Clay Minerals, 21, 537–564.Google Scholar
Swarbrick, R.E. (1994) Reservoir diagenesis hydrocarbon migration under hydrostatic palaeopressure conditions. Clay Minerals, 29, 463–473.Google Scholar
Taylor, D.J. & Dietvorst, J.P.A. (1991) The Cormorant Field, Blocks 211/21a, 211/26a, UK North Sea. Pp. 73–81 in: United Kingdom Oil and Gas Fields 25 Years Commemorative Volume (Abbotts, I.L., editor). Memoir, 14. Geological Society, London.Google Scholar
Thomas, M. (1986) Diagenetic sequences and K-Ar dating in Jurassic sandstones, central Viking Graben: effects on reservoir properties. Clay Minerals, 21, 695–710.Google Scholar
Velde, B. (1977) A proposed phase diagram for illite, expanding chlorite, corrensite and illite-montmor-illonite mixed layer minerals. Clays and Clay Minerals, 25, 264–270.Google Scholar
Velde, B. & Nicot, E. (1985) Diagenetic clay mineral composition as a function of pressure, temperature, and chemical activity. Journal of Sedimentary Petrology, 55, 541–547.Google Scholar
Watson, R.S. (1993) The diagenesis of Tertiary sands from the Forth & Balmoral Fields, Northern North Sea. Unpublished PhD thesis, University of Aberdeen, UK.Google Scholar
Watson, R.S., Trewin, N.H. & Fallick, A.E. (1995) The formation of carbonate cements in the Forth & Balmoral Fields, northern North Sea; a case for biodegredation, carbonate cementation and oil leakage during early burial. Pp. 177–200 in: Characterisation of Deep Marine Clastic Systems (Hartley, A.J. & Prosser, D.J., editors). Special Publication, 94. Geological Society, London.Google Scholar
Wensaas, L., Shaw, H.F., Gibbon, S.K., Aagaard, P. & Dypvik, H. (1994) Nature and causes of overpressur-ing in mudrocks of the Gullfaks area, North Sea. Clay Minerals, 29, 439–449.Google Scholar
Wilkinson, M. & Haszeldine, R.S. (2002a) Fibrous illite in oilfield sandstones – a nucleation kinetic theory of growth. Terra Nova, 14, 56–60.Google Scholar
Wilkinson, M. & Haszeldine, R.S. (2002b) Problems with argon: K-Ar ages in Gulf Coast shales. Chemical Geology, 191, 277–283.Google Scholar
Wilkinson, M., Fallick, A.E., Keaney, G.M.J., Haszeldine, R.S. & McHardy, W. (1994) Stable isotopes in illite: the case for meteoric water flushing within the Upper Jurassic Fulmar Formation sandstones, UK North Sea. Clay Minerals, 29, 567–574.Google Scholar
Wilkinson, M., Haszeldine, R.S. & Fallick, A.E. (2004) Hydrocarbon filling history from diagenetic evidence: Brent Group, UK North Sea. Marine and Petroleum Geology, 21, 443–455.Google Scholar
Worden, R.H. & Morad, S. (2003) Clay minerals in sandstones: controls on formation, distribution and evolution. Pp. 3–42 in: Clay Mineral Cements in Sandstones (Worden, R.H. & Morad, S., editors). Special Publication, 34. International Association of Sedimentologists.Google Scholar