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The Sleipner Effect: a subtle relationship between the distribution of diagenetic clay, reservoir porosity, permeability, and water saturation

Published online by Cambridge University Press:  09 July 2018

P. H. Nadeau*
Affiliation:
Statoil a.s, 4035 Stavanger, Norway
*

Abstract

Petrographic, mineralogical and geochemical core analysis of Palaeocene turbiditic sandstones in the Sleipner East gas-condensate reservoirs show the importance of diagenetic clay distribution on porosity, permeability, and water saturation. An observed ‘high resistivity zone’ (HRZ) corresponds to intervals with low water saturation, a more restricted distribution of diagenetic clay (mainly chlorite), and up to 5% quartz cement. The underlying ‘low resistivity zone’ (LRZ) corresponds to intervals with more widely distributed diagenetic clay, which have lower degrees of quartz cementation, higher porosity, and variably reduced permeability. Crosscutting relationships of the HRZ/LRZ with mapped sedimentary depositional units, as well as fluid inclusion analysis data, suggest that the distribution of diagenetic clay was affected by an earlier (late Miocene?) oil charge, and more extensive chlorite formation in a palaeo-water zone. Recent gas condensate charge and structuring of these sandstones resulted in LRZ reservoirs with substantially higher water saturations than those in the HRZ.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

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References

Bjørkum, P.A. & Nadeau, P.H. (1998) Temperature controlled porosity/permeability reduction, fluid migration, and petroleum exploration in sedimentary basins. Austral. Petrol. Prod. Expl. Assoc. J. 38, 38453.Google Scholar
Bjørkum, P.A., Oelkers, E.H., Nadeau, P.H., Walderhaug, O. & Murphy, W.M. (1998) Porosity prediction in sandstones as a function of time, temperature, depth, stylolite frequency, and hydrocarbon saturation. Am. Assoc. Petrol. Geol. Bull. 82, 82637.Google Scholar
Ehrenberg, S.N. (1993) Preservation of anomalously high porosity in deeply buried sandstones by graincoating chlorite: Examples from the Norwegian Continental Shelf. Am. Assoc. Petrol. Geol. Bull. 77, 771260.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 Miner. 24, 24233.CrossRefGoogle Scholar
Ehrenberg, S.N., Dalland, A., Nadeau, P.H., Mearns, E.W. & Amundsen, H. (1998) Origin of chlorite enrichment and neodymium isotopic anomalies in Haltenbanken sandstones. Marine Petrol. Geol. 15, 15403.Google Scholar
Hurst, A. & Buller, T. (1984) Dish structures in some Paleocene deep-sea sandstones (Norwegian Sector, North Sea): Origin of the dish-forming clays and their effects on reservoir quality. J. Sed. Pet. 54, 541206.Google Scholar
Hurst, A. & Nadeau, P.H. (1995) Clay microporosity in reservoir sandstones: An application of quantitative electron microscopy in petrophysical evaluation. Am. Assoc. Petrol. Geol. Bull. 79, 79563.Google Scholar
McHardy, W.J. & Birnie, A.C. (1987) Scanning electron microscopy. Pp. 174-208 in: A Handbook of Determinative Methods in Clay Mineralogy (Wilson, M.J., editor). Blackie, Glasgow.Google Scholar
Nadeau, P.H. (1998) An experimental study of the effects of diagenetic clay minerals in reservoir sands. Clays Clay Miner. 46, 4618.CrossRefGoogle Scholar
Nadeau, P.H. & Hurst, A. (1991) Application of backscattered SEM to the quantification of clay microporosity in sandstones. J. Sed. Pet. 61, 61921.Google Scholar
Nadeau, P.H. & Eliassen, P.E. (1996) Dating of igneous intrusives and burial/thermal history by illite geochronology of clay diagenesis in shales. Am. Assoc. Petrol. Geol. Ann. Conv. Prog. Abstracts, A103.Google Scholar
Nadeau, P.H., Bjørkum, P.A. & Walderhaug, O. (1997) Sedimentologic controls on diagenetic processes in sandstones. Pp. 121-124 in: I Latin Congress on Sedimentology, Vol. 2. Geological Society of Venezuela, Spec. Publ. Caracas.Google Scholar
Nadeau, P.H., Hillier, S., Boe, R. & Lieng, E. (1999) Chlorite diagenesis in sandstones: Impact on reservoir properties. Conf. Euro. Clay Groups Assoc, Cracow, Program Abstracts, 115.Google Scholar
Patience, R.L., van Graas, G., Knudsen, K., Berge, E., Fløtre, A.B., Gilje, A.E., Due, A., Skadsem-Eikelmann, K. & Nadeau, P.H. (1995) Determination of oil-water and gas-water contacts from simple geochemistry methods. Pp. 358-360 in: Organic Geochemistry: Developments and Applications to Energy, Climate, Environment and Human History (Grimait, J.O. & Dorronsoro, C., editors). AIGOA Publication, San Sebastian.Google Scholar
Pegrum, R.M. & Ljones, T.E. (1984) 15/9 Gamma Gas Field Offshore Norway, new trap type for North Sea Basin with regional structural implications. Am. Assoc. Petrol. Geol. Bull. 68, 68874.Google Scholar
Pevear, D.R. (1992) Hike age analysis, a new tool for basin thermal history analysis. Pp. 1251-1254 in: Water Rock Interaction, Proc. 7th Int. Symp. Water-Rock Interaction. (Kharaka, Y.K. & Maest, A.S., editors). A.A. Balkema, Rotterdam.Google Scholar
Rittenhouse, G. (1967) Bromine in oil-field waters and its use in determining possibilities of origin of these waters. Am. Assoc. Petrol. Geol. Bull. 51, 512430.Google Scholar
Strømmen, S.K., Halvorsen C, Langlais, V., Laursen, G., Nadeau, P.H. & Samuelsen, E.T. (1998) Sleipner 0st Field, a sand-rich Palaeocene (Ty Formation) gascondensate reservoir offshore Norway: Sedimentology, stratigraphy, heterogeneity and paleocontact influence on reservoir properties, flow and production. EAGE/AAPG Third Research Symposium, Spain, Abstract A014.Google Scholar
Waxman, M.H. & Smits, L.J.M. (1968) Electrical conductivity in oil-bearing shaly sands. Soc. Petrol. Eng. J. 8, 8107.CrossRefGoogle Scholar